• Here, Arctic sea ice is enhanced by pumping water on the sea ice surface to thicken the ice. This technology is sometimes referred to as Arctic Ice Management (AIM). Several institutions are currently developing and testing this technology including the Centre for Climate Repair at the University of Cambridge, Real Ice, and Arctic Reflections (in collaboration with Delft University and The University Centre in Svalbard). Arctic Reflections is exploring the use of large-scale offshore pumping sites, leveraging natural ice movement as a way of distributing the thickened ice. These groups are also collaborating with each other. Real Ice is developing a water pumping system attached to an underwater drone with a hydrogen fuel cell energy system. With their proposed technique, sea ice is flooded with seawater to thicken sea ice and to remove the insulating snow layer at the beginning of winter. At the end of winter, if required, snow is re-applied to areas to increase albedo and provide insulation during the warmer months.

• Expected physical changes (global)
  • Likely none.
• Expected physical changes (Arctic region)
  • Sea ice is thickened, potentially preventing ice melt and prolonging sea ice stability.

• 100,000-1,406,000 km², dependent on goal
  • 10% of Arctic Ocean suggested for deployment (1,406,000 km²; Desch et al. 2017).
  • Real Ice estimated that re-icing and thickening 1,000,000 km² of sea ice every year (adding 70 cm of additional thickness for total of 700 km³ additional ice volume) would preserve the current 4,00,000 km² of September sea ice and move toward levels recorded in the 1980s (approximately 7,000,000 km²) as the annual loss of sea ice volume would be more than offset.
  • Arctic Reflections is targeting specific locations within the Arctic Ocean to maximize ice distribution. The goal is to prevent 100,000 km² of melting via 100-1,000 sites, with the aim to stabilize summer sea ice.

• Sea ice surface

• Existing sea ice areas in the Arctic Ocean; most effective in areas becoming ice-free in the summer (i.e., where sea ice would otherwise melt and convert to open water, for example, the Beaufort Sea; van Dijke in review).

• Effective during summer preventing melt, likely deployed in fall or winter
  • In this approach, sea ice is flooded with seawater to thicken sea ice and remove the insulating snow layer at the beginning of winter. At the end of winter, where required, snow could be applied to increase albedo and provide insulation, with the goal of decreasing summer ice melt. van Dijke (2022) recommends applying this technology late in the winter season to obtain maximum thickness and minimize the freezing duration after flooding.
  • Pauling and Bitz (2021) recommended that this technique would be most effective at the start of the sea ice growth season in September when snowfall begins to accumulate. This study found no advantage for flooding for 6 months vs 2 months. Beneficial flooding amount was 20 cm/yr, which would add a total of 70 cm extra ice thickness due to reduced snow insulation. Flooding 20 cm of snow will require, on average, 15 cm of seawater (with snow approximately 310 kg/m³).

• Here, Arctic sea ice is enhanced by pumping water on the sea ice surface to thicken the ice. This technology is sometimes referred to as Arctic Ice Management (AIM). Several institutions are currently developing and testing this technology including the Centre for Climate Repair at the University of Cambridge, Real Ice, and Arctic Reflections (in collaboration with Delft University and The University Centre in Svalbard). Arctic Reflections is exploring the use of large-scale offshore pumping sites, leveraging natural ice movement as a way of distributing the thickened ice. These groups are also collaborating with each other. Real Ice is developing a water pumping system attached to an underwater drone with a hydrogen fuel cell energy system. With their proposed technique, sea ice is flooded with seawater to thicken sea ice and to remove the insulating snow layer at the beginning of winter. At the end of winter, if required, snow is re-applied to areas to increase albedo and provide insulation during the warmer months.

• Expected physical changes (global)
  • Likely none.
• Expected physical changes (Arctic region)
  • Sea ice is thickened, potentially preventing ice melt and prolonging sea ice stability.

• 100,000-1,406,000 km², dependent on goal
  • 10% of Arctic Ocean suggested for deployment (1,406,000 km²; Desch et al. 2017).
  • Real Ice estimated that re-icing and thickening 1,000,000 km² of sea ice every year (adding 70 cm of additional thickness for total of 700 km³ additional ice volume) would preserve the current 4,00,000 km² of September sea ice and move toward levels recorded in the 1980s (approximately 7,000,000 km²) as the annual loss of sea ice volume would be more than offset.
  • Arctic Reflections is targeting specific locations within the Arctic Ocean to maximize ice distribution. The goal is to prevent 100,000 km² of melting via 100-1,000 sites, with the aim to stabilize summer sea ice.

• Sea ice surface

• Existing sea ice areas in the Arctic Ocean; most effective in areas becoming ice-free in the summer (i.e., where sea ice would otherwise melt and convert to open water, for example, the Beaufort Sea; van Dijke in review).

• Effective during summer preventing melt, likely deployed in fall or winter
  • In this approach, sea ice is flooded with seawater to thicken sea ice and remove the insulating snow layer at the beginning of winter. At the end of winter, where required, snow could be applied to increase albedo and provide insulation, with the goal of decreasing summer ice melt. van Dijke (2022) recommends applying this technology late in the winter season to obtain maximum thickness and minimize the freezing duration after flooding.
  • Pauling and Bitz (2021) recommended that this technique would be most effective at the start of the sea ice growth season in September when snowfall begins to accumulate. This study found no advantage for flooding for 6 months vs 2 months. Beneficial flooding amount was 20 cm/yr, which would add a total of 70 cm extra ice thickness due to reduced snow insulation. Flooding 20 cm of snow will require, on average, 15 cm of seawater (with snow approximately 310 kg/m³).

• Here, Arctic sea ice is enhanced by pumping water on the sea ice surface to thicken the ice. This technology is sometimes referred to as Arctic Ice Management (AIM). Several institutions are currently developing and testing this technology including the Centre for Climate Repair at the University of Cambridge, Real Ice, and Arctic Reflections (in collaboration with Delft University and The University Centre in Svalbard). Arctic Reflections is exploring the use of large-scale offshore pumping sites, leveraging natural ice movement as a way of distributing the thickened ice. These groups are also collaborating with each other. Real Ice is developing a water pumping system attached to an underwater drone with a hydrogen fuel cell energy system. With their proposed technique, sea ice is flooded with seawater to thicken sea ice and to remove the insulating snow layer at the beginning of winter. At the end of winter, if required, snow is re-applied to areas to increase albedo and provide insulation during the warmer months.

• Expected physical changes (global)
  • Likely none.
• Expected physical changes (Arctic region)
  • Sea ice is thickened, potentially preventing ice melt and prolonging sea ice stability.

• 100,000-1,406,000km², dependent on goal
  • 10% of Arctic Ocean suggested for deployment (1,406,000 km²; Desch et al. 2017).
  • Real Ice estimated that re-icing and thickening 1,000,000 km² of sea ice every year (adding 70 cm of additional thickness for total of 700 km³ additional ice volume) would preserve the current 4,00,000 km² of September sea ice and move toward levels recorded in the 1980s (approximately 7,000,000 km²) as the annual loss of sea ice volume would be more than offset.
  • Arctic Reflections is targeting specific locations within the Arctic Ocean to maximize ice distribution. The goal is to prevent 100,000 km² of melting via 100-1,000 sites, with the aim to stabilize summer sea ice.

• Sea ice surface

• Existing sea ice areas in the Arctic Ocean; most effective in areas becoming ice-free in the summer (i.e., where sea ice would otherwise melt and convert to open water, for example, the Beaufort Sea; van Dijke in review).

• Effective during summer preventing melt, likely deployed in fall or winter
  • In this approach, sea ice is flooded with seawater to thicken sea ice and remove the insulating snow layer at the beginning of winter. At the end of winter, where required, snow could be applied to increase albedo and provide insulation, with the goal of decreasing summer ice melt. van Dijke (2022) recommends applying this technology late in the winter season to obtain maximum thickness and minimize the freezing duration after flooding.
  • Pauling and Bitz (2021) recommended that this technique would be most effective at the start of the sea ice growth season in September when snowfall begins to accumulate. This study found no advantage for flooding for 6 months vs 2 months. Beneficial flooding amount was 20 cm/yr, which would add a total of 70 cm extra ice thickness due to reduced snow insulation. Flooding 20 cm of snow will require, on average, 15 cm of seawater (with snow approximately 310 kg/m³).

• Here, Arctic sea ice is enhanced by pumping water on the sea ice surface to thicken the ice. This technology is sometimes referred to as Arctic Ice Management (AIM). Several institutions are currently developing and testing this technology including the Centre for Climate Repair at the University of Cambridge, Real Ice, and Arctic Reflections (in collaboration with Delft University and The University Centre in Svalbard). Arctic Reflections is exploring the use of large-scale offshore pumping sites, leveraging natural ice movement as a way of distributing the thickened ice. These groups are also collaborating with each other. Real Ice is developing a water pumping system attached to an underwater drone with a hydrogen fuel cell energy system. With their proposed technique, sea ice is flooded with seawater to thicken sea ice and to remove the insulating snow layer at the beginning of winter. At the end of winter, if required, snow is re-applied to areas to increase albedo and provide insulation during the warmer months.

• Expected physical changes (global)
  • Likely none.
• Expected physical changes (Arctic region)
  • Sea ice is thickened, potentially preventing ice melt and prolonging sea ice stability.

• 100,000-1,406,000km², dependent on goal
  • 10% of Arctic Ocean suggested for deployment (1,406,000km²; Desch et al. 2017).
  • Real Ice estimated that re-icing and thickening 1,000,000km² of sea ice every year (adding 70 cm of additional thickness for total of 700 km³ additional ice volume) would preserve the current 4,00,000km² of September sea ice and move toward levels recorded in the 1980s (approximately 7,000,000km²) as the annual loss of sea ice volume would be more than offset.
  • Arctic Reflections is targeting specific locations within the Arctic Ocean to maximize ice distribution. The goal is to prevent 100,000 km² of melting via 100-1,000 sites, with the aim to stabilize summer sea ice.

• Sea ice surface

• Existing sea ice areas in the Arctic Ocean; most effective in areas becoming ice-free in the summer (i.e., where sea ice would otherwise melt and convert to open water, for example, the Beaufort Sea; van Dijke in review).

• Effective during summer preventing melt, likely deployed in fall or winter
  • In this approach, sea ice is flooded with seawater to thicken sea ice and remove the insulating snow layer at the beginning of winter. At the end of winter, where required, snow could be applied to increase albedo and provide insulation, with the goal of decreasing summer ice melt. van Dijke (2022) recommends applying this technology late in the winter season to obtain maximum thickness and minimize the freezing duration after flooding.
  • Pauling and Bitz (2021) recommended that this technique would be most effective at the start of the sea ice growth season in September when snowfall begins to accumulate. This study found no advantage for flooding for 6 months vs 2 months. Beneficial flooding amount was 20 cm/yr, which would add a total of 70 cm extra ice thickness due to reduced snow insulation. Flooding 20 cm of snow will require, on average, 15 cm of seawater (with snow approximately 310 kg/m³).

• Here, Arctic sea ice is enhanced by pumping water on the sea ice surface to thicken the ice. This technology is sometimes referred to as Arctic Ice Management (AIM). Several institutions are currently developing and testing this technology including the Centre for Climate Repair at the University of Cambridge, Real Ice, and Arctic Reflections (in collaboration with Delft University and The University Centre in Svalbard). Arctic Reflections is exploring the use of large-scale offshore pumping sites, leveraging natural ice movement as a way of distributing the thickened ice. These groups are also collaborating with each other. Real Ice is developing a water pumping system attached to an underwater drone with a hydrogen fuel cell energy system. With their proposed technique, sea ice is flooded with seawater to thicken sea ice and to remove the insulating snow layer at the beginning of winter. At the end of winter, if required, snow is re-applied to areas to increase albedo and provide insulation during the warmer months.

• Expected physical changes (global)
  • Likely none
• Expected physical changes (Arctic region)
  • Sea ice is thickened, potentially preventing ice melt and prolonging sea ice stability

• 100,000-1,406,000km², dependent on goal
  • 10% of Arctic Ocean suggested for deployment (1,406,000km²; Desch et al. 2017).
  • Real Ice estimated that re-icing and thickening 1,000,000km² of sea ice every year (adding 70 cm of additional thickness for total of 700 km³ additional ice volume) would preserve the current 4,00,000km² of September sea ice and move toward levels recorded in the 1980s (approximately 7,000,000km²) as the annual loss of sea ice volume would be more than offset.
  • Arctic Reflections is targeting specific locations within the Arctic Ocean to maximize ice distribution. The goal is to prevent 100,000 km² of melting via 100-1,000 sites, with the aim to stabilize summer sea ice.

• Sea ice surface

• Existing sea ice areas in Arctic Ocean; most effective in areas becoming ice free in the summer (i.e., where sea ice would otherwise melt and convert to open water, for example, the Beaufort Sea; van Dijke in review)

• Effective during summer preventing melt, likely deployed in fall or winter
  • In this approach sea ice is flooded with seawater to thicken sea ice and to remove the insulating snow layer at the beginning of winter. At the end of winter, where required, snow could be applied to increase albedo and provide insulation, with the goal of decreasing summer ice melt. van Dijke (2022) recommends applying this technology late in the winter season to obtain maximum thickness and minimize the freezing duration after flooding.
  • Pauling and Bitz (2021) recommended that this technique would be most effective at the start of the sea ice growth season in September when snowfall begins to accumulate. This study found no advantage for flooding for 6 months vs 2 months. Beneficial flooding amount was 20 cm/yr, which would add a total of 70 cm extra ice thickness due to reduced snow insulation. Flooding 20 cm of snow will require, on average, 15 cm of sea water (with snow approximately 310 kg/m³).

• Here, Arctic sea ice is enhanced by pumping water on the sea ice surface to thicken the ice. This technology is sometimes referred to as Arctic Ice Management (AIM). Several institutions are currently developing and testing this technology including the Centre for Climate Repair at the University of Cambridge, Real Ice, and Arctic Reflections (in collaboration with Delft University and The University Centre in Svalbard). Arctic Reflections is exploring the use of large-scale offshore pumping sites, leveraging natural ice movement as a way of distributing the thickened ice. These groups are also collaborating with each other. Real Ice is developing a water pumping system attached to an underwater drone with a hydrogen fuel cell energy system. With their proposed technique, sea ice is flooded with seawater to thicken sea ice and to remove the insulating snow layer at the beginning of winter. At the end of winter, if required, snow is re-applied to areas to increase albedo and provide insulation during the warmer months.

• Expected physical changes (global)
  • Likely none
• Expected physical changes (Arctic region)
  • Sea ice is thickened, potentially preventing ice melt and prolonging sea ice stability

• 100,000-1,406,000km², dependent on goal
  • 10% of Arctic Ocean suggested for deployment (1,406,000km²; Desch et al. 2017).
  • Real Ice estimated that re-icing and thickening 1,000,000km² of sea ice every year (adding 70 cm of additional thickness for total of 700 km³ additional ice volume) would preserve the current 4,00,000km² of September sea ice and move toward levels recorded in the 1980s (approximately 7,000,000km²) as the annual loss of sea ice volume would be more than offset.
  • Arctic Reflections is targeting specific locations within the Arctic Ocean to maximize ice distribution. The goal is to prevent 100,000 km² of melting via 100-1,000 sites, with the aim to stabilize summer sea ice.

• Sea ice surface

• Existing sea ice areas in Arctic Ocean; most effective in areas becoming ice free in the summer (i.e., where sea ice would otherwise melt and convert to open water, for example, the Beaufort Sea; van Dijke in review)

• Effective during summer preventing melt, likely deployed in fall or winter
  • In this approach sea ice is flooded with seawater to thicken sea ice and to remove the insulating snow layer at the beginning of winter. At the end of winter, where required, snow could be applied to increase albedo and provide insulation, with the goal of decreasing summer ice melt. van Dijke (2022) recommends applying this technology late in the winter season to obtain maximum thickness and minimize the freezing duration after flooding.
  • Pauling and Bitz (2021) recommended that this technique would be most effective at the start of the sea ice growth season in September when snowfall begins to accumulate. This study found no advantage for flooding for 6 months vs 2 months. Beneficial flooding amount was 20 cm/yr, which would add a total of 70 cm extra ice thickness due to reduced snow insulation. Flooding 20 cm of snow will require, on average, 15 cm of sea water (with snow approximately 310 kg/m³).

• Here, Arctic sea ice is enhanced by pumping water on the sea ice surface to thicken the ice. This technology is sometimes referred to as Arctic Ice Management (AIM). Several institutions are currently developing and testing this technology including the Centre for Climate Repair at the University of Cambridge, Real Ice, and Arctic Reflections (in collaboration with Delft University and The University Centre in Svalbard). Arctic Reflections is exploring the use of large-scale offshore pumping sites, leveraging natural ice movement as a way of distributing the thickened ice. These groups are also collaborating with each other. Real Ice is developing a water pumping system attached to an underwater drone with a hydrogen fuel cell energy system. With their proposed technique, sea ice is flooded with seawater to thicken sea ice and to remove the insulating snow layer at the beginning of winter. At the end of winter, if required, snow is re-applied to areas to increase albedo and provide insulation during the warmer months.

• Expected physical changes (global)
  • Likely none
• Expected physical changes (Arctic region)
  • Sea ice is thickened, potentially preventing ice melt and prolonging sea ice stability

• 100,000-1,406,000km², dependent on goal
  • 10% of Arctic Ocean suggested for deployment (1,406,000km²; Desch et al. 2017).
  • Real Ice estimated that re-icing and thickening 1,000,000km² of sea ice every year (adding 70 cm of additional thickness for total of 700 km³ additional ice volume) would preserve the current 4,00,000km² of September sea ice and move toward levels recorded in the 1980s (approximately 7,000,000km²) as the annual loss of sea ice volume would be more than offset.
  • Arctic Reflections is targeting specific locations within the Arctic Ocean to maximize ice distribution. The goal is to prevent 100,000 km² of melting via 100-1,000 sites, with the aim to stabilize summer sea ice.

• Sea ice surface

• Existing sea ice areas in Arctic Ocean; most effective in areas becoming ice free in the summer (i.e., where sea ice would otherwise melt and convert to open water, for example, the Beaufort Sea; van Dijke in review)

• Effective during summer preventing melt, likely deployed in fall or winter
  • In this approach sea ice is flooded with seawater to thicken sea ice and to remove the insulating snow layer at the beginning of winter. At the end of winter, where required, snow could be applied to increase albedo and provide insulation, with the goal of decreasing summer ice melt. van Dijke (2022) recommends applying this technology late in the winter season to obtain maximum thickness and minimize the freezing duration after flooding.
  • Pauling and Bitz (2021) recommended that this technique would be most effective at the start of the sea ice growth season in September when snowfall begins to accumulate. This study found no advantage for flooding for 6 months vs 2 months. Beneficial flooding amount was 20 cm/yr, which would add a total of 70 cm extra ice thickness due to reduced snow insulation. Flooding 20 cm of snow will require, on average, 15 cm of sea water (with snow approximately 310 kg/m³).

• Here, Arctic sea ice is enhanced by pumping water on the sea ice surface to thicken the ice. This technology is sometimes referred to as Arctic Ice Management (AIM). Several institutions are currently developing and testing this technology including the Centre for Climate Repair at the University of Cambridge, Real Ice, and Arctic Reflections (in collaboration with Delft University and The University Centre in Svalbard). Arctic Reflections is exploring the use of large-scale offshore pumping sites, leveraging natural ice movement as a way of distributing the thickened ice. These groups are also collaborating with each other. Real Ice is developing a water pumping system attached to an underwater drone with a hydrogen fuel cell energy system. With their proposed technique, sea ice is flooded with seawater to thicken sea ice and to remove the insulating snow layer at the beginning of winter. At the end of winter, if required, snow is re-applied to areas to increase albedo and provide insulation during the warmer months.

• Expected physical changes (global)
  • Likely none
• Expected physical changes (Arctic region)
  • Sea ice is thickened, potentially preventing ice melt and prolonging sea ice stability

• 100,000-1,406,000km², dependent on goal
  • 10% of Arctic Ocean suggested for deployment (1,406,000km²; Desch et al. 2017).
  • Real Ice estimated that re-icing and thickening 1,000,000km² of sea ice every year (adding 70 cm of additional thickness for total of 700 km³ additional ice volume) would preserve the current 4,00,000km² of September sea ice and move toward levels recorded in the 1980s (approximately 7,000,000km²) as the annual loss of sea ice volume would be more than offset.
  • Arctic Reflections is targeting specific locations within the Arctic Ocean to maximize ice distribution. The goal is to prevent 100,000 km² of melting via 100-1,000 sites, with the aim to stabilize summer sea ice.

• Sea ice surface

• Existing sea ice areas in Arctic Ocean; most effective in areas becoming ice free in the summer (i.e., where sea ice would otherwise melt and convert to open water, for example, the Beaufort Sea; van Dijke in review)

• Effective during summer preventing melt, likely deployed in fall or winter
  • In this approach sea ice is flooded with seawater to thicken sea ice and to remove the insulating snow layer at the beginning of winter. At the end of winter, where required, snow could be applied to increase albedo and provide insulation, with the goal of decreasing summer ice melt. van Dijke (2022) recommends applying this technology late in the winter season to obtain maximum thickness and minimize the freezing duration after flooding.
  • Pauling and Bitz (2021) recommended that this technique would be most effective at the start of the sea ice growth season in September when snowfall begins to accumulate. This study found no advantage for flooding for 6 months vs 2 months. Beneficial flooding amount was 20 cm/yr, which would add a total of 70 cm extra ice thickness due to reduced snow insulation. Flooding 20 cm of snow will require, on average, 15 cm of sea water (with snow approximately 310 kg/m³).

• Here, Arctic sea ice is enhanced by pumping water on the sea ice surface to thicken the ice. This technology is sometimes referred to as Arctic Ice Management (AIM). Several institutions are currently developing and testing this technology including the Centre for Climate Repair at the University of Cambridge, Real Ice, and Arctic Reflections (in collaboration with Delft University and The University Centre in Svalbard). Arctic Reflections is exploring the use of large-scale offshore pumping sites, leveraging natural ice movement as a way of distributing the thickened ice. These groups are also collaborating with each other. Real Ice is developing a water pumping system attached to an underwater drone with a hydrogen fuel cell energy system. With their proposed technique, sea ice is flooded with seawater to thicken sea ice and to remove the insulating snow layer at the beginning of winter. At the end of winter, if required, snow is re-applied to areas to increase albedo and provide insulation during the warmer months.

• Expected physical changes (global)
  • Likely none
• Expected physical changes (Arctic region)
  • Sea ice is thickened, potentially preventing ice melt and prolonging sea ice stability

• 100,000-1,406,000km², dependent on goal
  • 10% of Arctic Ocean suggested for deployment (1,406,000km²; Desch et al. 2017).
  • Real Ice estimated that re-icing and thickening 1,000,000km² of sea ice every year (adding 70 cm of additional thickness for total of 700 km³ additional ice volume) would preserve the current 4,00,000km² of September sea ice and move toward levels recorded in the 1980s (approximately 7,000,000km²) as the annual loss of sea ice volume would be more than offset.
  • Arctic Reflections is targeting specific locations within the Arctic Ocean to maximize ice distribution. The goal is to prevent 100,000 km² of melting via 100-1,000 sites, with the aim to stabilize summer sea ice.

• Sea ice surface

• Existing sea ice areas in Arctic Ocean; most effective in areas becoming ice free in the summer (i.e., where sea ice would otherwise melt and convert to open water, for example, the Beaufort Sea; van Dijke in review)

• Effective during summer preventing melt, likely deployed in fall or winter
  • In this approach sea ice is flooded with seawater to thicken sea ice and to remove the insulating snow layer at the beginning of winter. At the end of winter, where required, snow could be applied to increase albedo and provide insulation, with the goal of decreasing summer ice melt. van Dijke (2022) recommends applying this technology late in the winter season to obtain maximum thickness and minimize the freezing duration after flooding.
  • Pauling and Bitz (2021) recommended that this technique would be most effective at the start of the sea ice growth season in September when snowfall begins to accumulate. This study found no advantage for flooding for 6 months vs 2 months. Beneficial flooding amount was 20 cm/yr, which would add a total of 70 cm extra ice thickness due to reduced snow insulation. Flooding 20 cm of snow will require, on average, 15 cm of sea water (with snow approximately 310 kg/m³).

• Here, Arctic sea ice is enhanced by pumping water on the sea ice surface to thicken the ice. This technology is sometimes referred to as Arctic Ice Management (AIM). Several institutions are currently developing and testing this technology including the Centre for Climate Repair at the University of Cambridge, Real Ice, and Arctic Reflections (in collaboration with Delft University and The University Centre in Svalbard). Arctic Reflections is exploring the use of large-scale offshore pumping sites, leveraging natural ice movement as a way of distributing the thickened ice. These groups are also collaborating with each other. Real Ice is developing a water pumping system attached to an underwater drone with a hydrogen fuel cell energy system. With their proposed technique, sea ice is flooded with seawater to thicken sea ice and to remove the insulating snow layer at the beginning of winter. At the end of winter, if required, snow is re-applied to areas to increase albedo and provide insulation during the warmer months.

• Expected physical changes (global)
  • Likely none
• Expected physical changes (Arctic region)
  • Sea ice is thickened, potentially preventing ice melt and prolonging sea ice stability

• 100,000-1,406,000km², dependent on goal
  • 10% of Arctic Ocean suggested for deployment (1,406,000km²; Desch et al. 2017).
  • Real Ice estimated that re-icing and thickening 1,000,000km² of sea ice every year (adding 70 cm of additional thickness for total of 700 km³ additional ice volume) would preserve the current 4,00,000km² of September sea ice and move toward levels recorded in the 1980s (approximately 7,000,000km²) as the annual loss of sea ice volume would be more than offset.
  • Arctic Reflections is targeting specific locations within the Arctic Ocean to maximize ice distribution. The goal is to prevent 100,000 km² of melting via 100-1,000 sites, with the aim to stabilize summer sea ice.

• Sea ice surface

• Existing sea ice areas in Arctic Ocean; most effective in areas becoming ice free in the summer (i.e., where sea ice would otherwise melt and convert to open water, for example, the Beaufort Sea; van Dijke in review)

• Effective during summer preventing melt, likely deployed in fall or winter
  • In this approach sea ice is flooded with seawater to thicken sea ice and to remove the insulating snow layer at the beginning of winter. At the end of winter, where required, snow could be applied to increase albedo and provide insulation, with the goal of decreasing summer ice melt. van Dijke (2022) recommends applying this technology late in the winter season to obtain maximum thickness and minimize the freezing duration after flooding.
  • Pauling and Bitz (2021) recommended that this technique would be most effective at the start of the sea ice growth season in September when snowfall begins to accumulate. This study found no advantage for flooding for 6 months vs 2 months. Beneficial flooding amount was 20 cm/yr, which would add a total of 70 cm extra ice thickness due to reduced snow insulation. Flooding 20 cm of snow will require, on average, 15 cm of sea water (with snow approximately 310 kg/m³).

• Here, Arctic sea ice is enhanced by pumping water on the sea ice surface to thicken the ice. This technology is sometimes referred to as Arctic Ice Management (AIM). Several institutions are currently developing and testing this technology including the Centre for Climate Repair at the University of Cambridge, Real Ice, and Arctic Reflections (in collaboration with Delft University and The University Centre in Svalbard). Arctic Reflections is exploring the use of large-scale offshore pumping sites, leveraging natural ice movement as a way of distributing the thickened ice. These groups are also collaborating with each other. Real Ice is developing a water pumping system attached to an underwater drone with a hydrogen fuel cell energy system. With their proposed technique, sea ice is flooded with seawater to thicken sea ice and to remove the insulating snow layer at the beginning of winter. At the end of winter, if required, snow is re-applied to areas to increase albedo and provide insulation during the warmer months.

• Expected physical changes (global)
  • Likely none
• Expected physical changes (Arctic region)
  • Sea ice is thickened, potentially preventing ice melt and prolonging sea ice stability

• 100,000-1,406,000km², dependent on goal
  • 10% of Arctic Ocean suggested for deployment (1,406,000km²; Desch et al. 2017).
  • Real Ice estimated that re-icing and thickening 1,000,000km² of sea ice every year (adding 70 cm of additional thickness for total of 700 km³ additional ice volume) would preserve the current 4,00,000km² of September sea ice and move toward levels recorded in the 1980s (approximately 7,000,000km²) as the annual loss of sea ice volume would be more than offset.
  • Arctic Reflections is targeting specific locations within the Arctic Ocean to maximize ice distribution. The goal is to prevent 100,000 km² of melting via 100-1,000 sites, with the aim to stabilize summer sea ice.

• Sea ice surface

• Existing sea ice areas in Arctic Ocean; most effective in areas becoming ice free in the summer (i.e., where sea ice would otherwise melt and convert to open water, for example, the Beaufort Sea; van Dijke in review)

• Effective during summer preventing melt, likely deployed in fall or winter
  • In this approach sea ice is flooded with seawater to thicken sea ice and to remove the insulating snow layer at the beginning of winter. At the end of winter, where required, snow could be applied to increase albedo and provide insulation, with the goal of decreasing summer ice melt. van Dijke (2022) recommends applying this technology late in the winter season to obtain maximum thickness and minimize the freezing duration after flooding.
  • Pauling and Bitz (2021) recommended that this technique would be most effective at the start of the sea ice growth season in September when snowfall begins to accumulate. This study found no advantage for flooding for 6 months vs 2 months. Beneficial flooding amount was 20 cm/yr, which would add a total of 70 cm extra ice thickness due to reduced snow insulation. Flooding 20 cm of snow will require, on average, 15 cm of sea water (with snow approximately ).

Impact on

• Variable; increases of 0.39-0.66 for thickening ice and adding snow, increases of 0.33 for prevention of sea ice melt and conversion to open water, potential decrease in albedo of 0.05-0.15 from flooding snow.
  • New ice has an albedo of 0.15-0.42 (depending on presence of snow; Webster and Warren 2022). By thickening ice and adding snow, albedo may be increased to 0.81 (Webster and Warren 2022; values reported here are for broadband clear skies, but that paper also provides values for visible and near-infrared albedo).
  • Thickening sea ice allows snow and sea ice to persist longer in summer where open water would otherwise occur, giving rise to an albedo of closer to 0.4 for multiyear ice compared to 0.7 for open water near the sea ice edge (Perovich and Polashenski 2012).
  • Flooding snow far to the north of the ice edge, however, can decrease albedo in the by 0.05-0.15 (Pauling and Bitz 2021).
  • Thickened ice in field and laboratory studies is whiter than natural ice, but it is unknown if that characteristic is maintained over time (van Dijke in review). The whitening of the ice is likely due to difference in salinity between the original ice and the flooded ice or to having more air trapped in the flooded ice layer (van Dijke in review).
  • Impacts will be dependent on time of year. Avoiding open water and postponing ice melt will be most effective in June and July (e.g., postponing open water by 10-30 days in July; F. Ypma pers. comm.).
  • Impacts will also be dependent on melt rate, which varies by region. For example, a modeling study shows that adding 30 cm of thickness corresponds to 1 month of additional ice in the Transpolar Drift area and 2 weeks in the Beaufort Sea (van Dijke in review).

• Global
  • Minimal (0.02°C) to no global cooling effect (Zampieri and Goessling 2019; Pauling and Bitz 2021).
    • In the modeling study by Zampieri and Goessling 2019 all sea ice north of 66.5°N during winter was thickened. In the modeling study by Pauling and Bitz 2021 sea ice covering the entire Arctic Ocean was thickened.
• Arctic region
  • Decreases in temperature in the Arctic of 1.3-2°C, with greatest decreases during summer.
    • A modeling study reported 1.3-1.4°C of cooling in the Arctic (Zampieri and Goessling 2019) during summer, plus warming in winter where pumps are active leading to net cooling in winter of 0.3°C and increases over time to warming of 0.5°C (2061-2100). The warm winter anomalies are due to maintaining a liquid water layer. In this study, all sea ice north of 66.5°N during winter was thickened.
    • A modeling study found up to 2°C cooling in the Arctic (Pauling and Bitz 2021) and noted that the temperature decrease was sensitive to the starting conditions. With less sea ice at the beginning of deployment the temperature decrease is less (Pauling and Bitz 2021). In this study sea ice covering the entire Arctic Ocean was thickened. This study used more realistic physical conditions than Zampieri and Goessling (2019) and did not find winter warming.

• Global
  • Decreases of approximately 0.25 W/m² in July, and 0.02-0.14 W/m² when averaged over the year.
    • A modeling study reports decreases in globally averaged solar radiative forcing from Arctic ice management of approximately 0.25 W/m² in July throughout the model time series (2021-2100). Averaged across the year, the decrease in globally averaged radiative forcing is a lot less, from approximately 0.02 W/m² (2021–2060) to 0.08 W/m² (2061–2100) (Zampieri and Goessling 2019). In this study, all sea ice north of 66.5°N during winter was thickened.
    • Desch et al. (2017) estimated global yearly averaged decline in radiative forcing of 0.14 W/m². In this study sea ice covering the entire Arctic Ocean was thickened.
• Arctic region
  • Decreased absorption of 0.008-6.5 W/m².
    • After 1 year of deployment, van Dijke (2022) estimated in a model that regional absorbed energy decreased 0.72-1.2%, corresponding to a change in radiative forcing of 0.008-0.013 W/m². These estimates are for application to the Beaufort Sea or Transpolar Drift.
    • A modeling study by Zampieri and Goessling (2019) showed increased reflected solar radiation in the Arctic during summer of approximately 5.0 W/m² from 2021-2060 and approximately 6.5 W/m² for 2061–2100. In this study, all sea ice north of 66.5°N during winter was thickened.
    • Pumping water on top of ice also has a temporary effect on outgoing longwave radiation (F. Ypma pers. comm.).

• Direct or indirect impact on sea ice?
  • Direct impact on sea ice via thickening and melt reduction.
• New or old ice?
  • Existing ice
    • van Dijke (2022) proposes to thicken first year ice as opposed to multi-year ice. Most newer marginal ice would otherwise be lost from the system, and the albedo modification benefits are the largest for first year ice.
• Impact on sea ice
  • Maintenance of summer sea ice for about 60 yrs, increases in thickness 0.7-1.0 m.
    • A modeling study demonstrated the potential to maintain summer sea ice cover for the next 60 yrs (Zampieri and Goessling 2019). In this study, all sea ice north of 66.5°N during winter was thickened.
    • A conceptual model reported potential increases in sea ice thickness up to 1 m (Desch et al. 2017). A follow-up modeling study estimated increased sea ice thickness of 70 cm with 20 cm of flooding (Pauling and Bitz 2021).
    • If Beaufort Gyre is targeted, ice is likely to remain in the area for 5-6 years. Ice can remain within the Transpolar Drift for 1-2 years (van Dijke 2022).
    • Importantly, the impact on sea ice will depend on what the goal of deployment is, and the scale of deployment. Decreasing the amount of solar radiation in the Arctic will require a large surface area and yearly application to stabilize summer sea ice extent. Increasing the amount of multi-year ice requires additional thickness.

Scalability

• Unknown, depends on goal
  • The plan laid out in Desch et al. (2017) is for 10% of the Arctic Ocean area (100,000,000 km²).
  • Zampieri and Goessling 2019 recommend 10,000,000 pumping devices covering approximately 0.1 km² each (10,000 km² total). If warming continues more devices would be required.
  • Arctic Reflections is targeting specific locations within the Arctic Ocean to maximize ice distribution. The goal is to prevent 100,000 km² of melting yearly via 100-1000 sites and stabilize summer sea ice extent.
    • Targeting the Beaufort Gyre may increase ice retention, while the Fram Strait, south of the Transpolar Drift, should be avoided due to the potential for ice export in this region (van Dijke 2022).
  • Real Ice is aiming for 1,000,000 km² of sea ice yearly to preserve current September sea ice extent and possibly restore September sea ice extent to levels from 1980s. They are targeting areas most at risk of summer melt or that could be restored to full-year coverage based on historical patterns and start of winter thickness.
  • Water volumes of 707-1,095 km³ (Beaufort Sea) and 386-464 km³ (Transpolar Drift) are required to avoid annual sea ice loss each year (322 km³ ice volume; 49,200 km² ice area; 83,400 km² ice extent; van Dijke 2022).

• Unknown
  • Some details on efficiency and efficacy of pumping and of flooding snow available in Desch et al. (2017), Pauling and Bitz (2021), and van Dijke (2022).
  • There are many tradeoffs that need to be considered related to timing, natural ice growth cycles, and impact on albedo (F. Ypma pers. comm.).

• Unknown
  • Real Ice and Arctic Reflections have plans to reach full scale in early 2030s.

• Unknown
  • To date studies of this technique have found minimal potential for global impact (Zampieri and Goessling 2019, Pauling and Bitz 2021).

• Unknown
  • To be effective this technology would need to happen as soon as possible. As Arctic sea ice area further decreases there will be less potential sea ice to apply this technique (Pauling and Bitz 2021). This concern depends on when the approach would be applied, with more ice being available during winter.
  • This technique may become technically feasible within 20 years, but deployment and Arctic impact would require achieving scalability, which may not be able to happen within 20 years.

Cost

• $ billions
  • Initial estimate of $500 billion to build 10 million wind-powered pumps to deploy this technology (Desch et al. 2017).
  • Real Ice estimates cost to $43 billion over first 10 years (approximately $6 billion per year once at full scale, re-icing 1,000,000 km²). This cost includes energy production and distribution, production and maintenance of engineering components, and personnel.
  • Arctic Reflections’ cost estimates for focusing on 100,000 km² of ice are $1-10 billion.

• Unknown; potential to use renewable energy
  • Desch et al. (2017) proposed to power the system using wind.
  • Real Ice has proposed powering underwater drones with hydrogen fuel cells. Wind or solar power would be used to create green hydrogen for use with the hydrogen fuel cells. They estimate it will take 8 MWh of energy to re-ice 1 km² of sea ice, including the start of winter and end of winter operations.
  • van Dijke (2022) suggests water volumes of 707-1,095 km³ (Beaufort Sea) and 386-464 km³ (Transpolar Drift) are required to avoid annual sea ice loss each year (322 km³ ice volume). The power required to pump this volume of water is 4.5-7.0 GW (Beaufort Sea) and 2.5-3.0 GW (Transpolar Drift).

Impact on

• Variable; increases of 0.39-0.66 for thickening ice and adding snow, increases of 0.33 for prevention of sea ice melt and conversion to open water, potential decrease in albedo of 0.05-0.15 from flooding snow.
  • New ice has an albedo of 0.15-0.42 (depending on presence of snow; Webster and Warren 2022). By thickening ice and adding snow, albedo may be increased to 0.81 (Webster and Warren 2022; values reported here are for broadband clear skies, but that paper also provides values for visible and near-infrared albedo).
  • Thickening sea ice allows snow and sea ice to persist longer in summer where open water would otherwise occur, giving rise to an albedo of closer to 0.4 for multiyear ice compared to 0.7 for open water near the sea ice edge (Perovich and Polashenski 2012).
  • Flooding snow far to the north of the ice edge, however, can decrease albedo in the by 0.05-0.15 (Pauling and Bitz 2021).
  • Thickened ice in field and laboratory studies is whiter than natural ice, but it is unknown if that characteristic is maintained over time (van Dijke in review). The whitening of the ice is likely due to difference in salinity between the original ice and the flooded ice or to having more air trapped in the flooded ice layer (van Dijke in review).
  • Impacts will be dependent on time of year. Avoiding open water and postponing ice melt will be most effective in June and July (e.g., postponing open water by 10-30 days in July; F. Ypma pers. comm.).
  • Impacts will also be dependent on melt rate, which varies by region. For example, a modeling study shows that adding 30 cm of thickness corresponds to 1 month of additional ice in the Transpolar Drift area and 2 weeks in the Beaufort Sea (van Dijke in review).

• Global
  • Minimal (0.02°C) to no global cooling effect (Zampieri and Goessling 2019; Pauling and Bitz 2021).
    • In the modeling study by Zampieri and Goessling 2019 all sea ice north of 66.5°N during winter was thickened. In the modeling study by Pauling and Bitz 2021 sea ice covering the entire Arctic Ocean was thickened.
• Arctic region
  • Decreases in temperature in the Arctic of 1.3-2°C, with greatest decreases during summer.
    • A modeling study reported 1.3-1.4°C of cooling in the Arctic (Zampieri and Goessling 2019) during summer, plus warming in winter where pumps are active leading to net cooling in winter of 0.3°C and increases over time to warming of 0.5°C (2061-2100). The warm winter anomalies are due to maintaining a liquid water layer. In this study, all sea ice north of 66.5°N during winter was thickened.
    • A modeling study found up to 2°C cooling in the Arctic (Pauling and Bitz 2021) and noted that the temperature decrease was sensitive to the starting conditions. With less sea ice at the beginning of deployment the temperature decrease is less (Pauling and Bitz 2021). In this study sea ice covering the entire Arctic Ocean was thickened. This study used more realistic physical conditions than Zampieri and Goessling (2019) and did not find winter warming.

• Global
  • Decreases of approximately 0.25 W/m² in July, and 0.02-0.14 W/m² when averaged over the year.
    • A modeling study reports decreases in globally averaged solar radiative forcing from Arctic ice management of approximately 0.25 W/m² in July throughout the model time series (2021-2100). Averaged across the year, the decrease in globally averaged radiative forcing is a lot less, from approximately 0.02 W/m² (2021–2060) to 0.08 W/m² (2061–2100) (Zampieri and Goessling 2019). In this study, all sea ice north of 66.5°N during winter was thickened.
    • Desch et al. (2017) estimated global yearly averaged decline in radiative forcing of 0.14 W/m². In this study sea ice covering the entire Arctic Ocean was thickened.
• Arctic region
  • Decreased absorption of 0.008-6.5 W/m².
    • After 1 year of deployment, van Dijke (2022) estimated in a model that regional absorbed energy decreased 0.72-1.2%, corresponding to a change in radiative forcing of 0.008-0.013 W/m². These estimates are for application to the Beaufort Sea or Transpolar Drift.
    • A modeling study by Zampieri and Goessling (2019) showed increased reflected solar radiation in the Arctic during summer of approximately 5.0 W/m² from 2021-2060 and approximately 6.5 W/m² for 2061–2100. In this study, all sea ice north of 66.5°N during winter was thickened.
    • Pumping water on top of ice also has a temporary effect on outgoing longwave radiation (F. Ypma pers. comm.).

• Direct or indirect impact on sea ice?
  • Direct impact on sea ice via thickening and melt reduction.
• New or old ice?
  • Existing ice
    • van Dijke (2022) proposes to thicken first year ice as opposed to multi-year ice. Most newer marginal ice would otherwise be lost from the system, and the albedo modification benefits are the largest for first year ice.
• Impact on sea ice
  • Maintenance of summer sea ice for about 60 yrs, increases in thickness 0.7-1.0 m.
    • A modeling study demonstrated the potential to maintain summer sea ice cover for the next 60 yrs (Zampieri and Goessling 2019). In this study, all sea ice north of 66.5°N during winter was thickened.
    • A conceptual model reported potential increases in sea ice thickness up to 1 m (Desch et al. 2017). A follow-up modeling study estimated increased sea ice thickness of 70 cm with 20 cm of flooding (Pauling and Bitz 2021).
    • If Beaufort Gyre is targeted, ice is likely to remain in the area for 5-6 years. Ice can remain within the Transpolar Drift for 1-2 years (van Dijke 2022).
    • Importantly, the impact on sea ice will depend on what the goal of deployment is, and the scale of deployment. Decreasing the amount of solar radiation in the Arctic will require a large surface area and yearly application to stabilize summer sea ice extent. Increasing the amount of multi-year ice requires additional thickness.

Scalability

• Unknown, depends on goal
  • The plan laid out in Desch et al. (2017) is for 10% of the Arctic Ocean area (100,000,000 km²).
  • Zampieri and Goessling 2019 recommend 10,000,000 pumping devices covering approximately 0.1 km² each (10,000 km² total). If warming continues more devices would be required.
  • Arctic Reflections is targeting specific locations within the Arctic Ocean to maximize ice distribution. The goal is to prevent 100,000 km² of melting yearly via 100-1000 sites and stabilize summer sea ice extent.
    • Targeting the Beaufort Gyre may increase ice retention, while the Fram Strait, south of the Transpolar Drift, should be avoided due to the potential for ice export in this region (van Dijke 2022).
  • Real Ice is aiming for 1,000,000 km² of sea ice yearly to preserve current September sea ice extent and possibly restore September sea ice extent to levels from 1980s. They are targeting areas most at risk of summer melt or that could be restored to full-year coverage based on historical patterns and start of winter thickness.
  • Water volumes of 707-1,095 km³ (Beaufort Sea) and 386-464 km³ (Transpolar Drift) are required to avoid annual sea ice loss each year (322 km³ ice volume; 49,200 km² ice area; 83,400 km² ice extent; van Dijke 2022).

• Unknown
  • Some details on efficiency and efficacy of pumping and of flooding snow available in Desch et al. (2017), Pauling and Bitz (2021), and van Dijke (2022).
  • There are many tradeoffs that need to be considered related to timing, natural ice growth cycles, and impact on albedo (F. Ypma pers. comm.).

• Unknown
  • Real Ice and Arctic Reflections have plans to reach full scale in early 2030s.

• Unknown
  • To date studies of this technique have found minimal potential for global impact (Zampieri and Goessling 2019, Pauling and Bitz 2021).

• Unknown
  • To be effective this technology would need to happen as soon as possible. As Arctic sea ice area further decreases there will be less potential sea ice to apply this technique (Pauling and Bitz 2021). This concern depends on when the approach would be applied, with more ice being available during winter.
  • This technique may become technically feasible within 20 years, but deployment and Arctic impact would require achieving scalability, which may not be able to happen within 20 years.

Cost

• $ billions
  • Initial estimate of $500 billion to build 10 million wind-powered pumps to deploy this technology (Desch et al. 2017).
  • Real Ice estimates cost to $43 billion over first 10 years (approximately $6 billion per year once at full scale, re-icing 1,000,000 km²). This cost includes energy production and distribution, production and maintenance of engineering components, and personnel.
  • Arctic Reflections’ cost estimates for focusing on 100,000 km² of ice are $1-10 billion.

• Unknown; potential to use renewable energy
  • Desch et al. (2017) proposed to power the system using wind.
  • Real Ice has proposed powering underwater drones with hydrogen fuel cells. Wind or solar power would be used to create green hydrogen for use with the hydrogen fuel cells. They estimate it will take 8MWh of energy to re-ice 1 km² of sea ice, including the start of winter and end of winter operations.
  • van Dijke (2022) suggests water volumes of 707-1,095 km³ (Beaufort Sea) and 386-464 km³ (Transpolar Drift) are required to avoid annual sea ice loss each year (322 km³ ice volume). The power required to pump this volume of water is 4.5-7.0 GW (Beaufort Sea) and 2.5-3.0 GW (Transpolar Drift).

Impact on

• Variable; increases of 0.39-0.66 for thickening ice and adding snow, increases of 0.33 for prevention of sea ice melt and conversion to open water, potential decrease in albedo of 0.05-0.15 from flooding snow.
  • New ice has an albedo of 0.15-0.42 (depending on presence of snow; Webster and Warren 2022). By thickening ice and adding snow, albedo may be increased to 0.81 (Webster and Warren 2022; values reported here are for broadband clear skies, but that paper also provides values for visible and near-infrared albedo).
  • Thickening sea ice allows snow and sea ice to persist longer in summer where open water would otherwise occur, giving rise to an albedo of closer to 0.4 for multiyear ice compared to 0.7 for open water near the sea ice edge (Perovich and Polashenski 2012).
  • Flooding snow far to the north of the ice edge, however, can decrease albedo in the by 0.05-0.15 (Pauling and Bitz 2021).
  • Thickened ice in field and laboratory studies is whiter than natural ice, but it is unknown if that characteristic is maintained over time (van Dijke in review). The whitening of the ice is likely due to difference in salinity between the original ice and the flooded ice or to having more air trapped in the flooded ice layer (van Dijke in review).
  • Impacts will be dependent on time of year. Avoiding open water and postponing ice melt will be most effective in June and July (e.g., postponing open water by 10-30 days in July; F. Ypma pers. comm.).
  • Impacts will also be dependent on melt rate, which varies by region. For example, a modeling study shows that adding 30 cm of thickness corresponds to 1 month of additional ice in the Transpolar Drift area and 2 weeks in the Beaufort Sea (van Dijke in review).

• Global
  • Minimal (0.02°C) to no global cooling effect (Zampieri and Goessling 2019; Pauling and Bitz 2021).
    • In the modeling study by Zampieri and Goessling 2019 all sea ice north of 66.5°N during winter was thickened. In the modeling study by Pauling and Bitz 2021 sea ice covering the entire Arctic Ocean was thickened.
• Arctic region
  • Decreases in temperature in the Arctic of 1.3-2°C, with greatest decreases during summer.
    • A modeling study reported 1.3-1.4°C of cooling in the Arctic (Zampieri and Goessling 2019) during summer, plus warming in winter where pumps are active leading to net cooling in winter of 0.3°C and increases over time to warming of 0.5°C (2061-2100). The warm winter anomalies are due to maintaining a liquid water layer. In this study, all sea ice north of 66.5°N during winter was thickened.
    • A modeling study found up to 2°C cooling in the Arctic (Pauling and Bitz 2021) and noted that the temperature decrease was sensitive to the starting conditions. With less sea ice at the beginning of deployment the temperature decrease is less (Pauling and Bitz 2021). In this study sea ice covering the entire Arctic Ocean was thickened. This study used more realistic physical conditions than Zampieri and Goessling (2019) and did not find winter warming.

• Global
  • Decreases of approximately 0.25 W/m² in July, and 0.02-0.14 W/m² when averaged over the year.
    • A modeling study reports decreases in globally averaged solar radiative forcing from Arctic ice management of approximately 0.25 W/m² in July throughout the model time series (2021-2100). Averaged across the year, the decrease in globally averaged radiative forcing is a lot less, from approximately 0.02 W/m² (2021–2060) to 0.08 W/m² (2061–2100) (Zampieri and Goessling 2019). In this study, all sea ice north of 66.5°N during winter was thickened.
    • Desch et al. (2017) estimated global yearly averaged decline in radiative forcing of 0.14 W/m². In this study sea ice covering the entire Arctic Ocean was thickened.
• Arctic region
  • Decreased absorption of 0.008-6.5 W/m².
    • After 1 year of deployment, van Dijke (2022) estimated in a model that regional absorbed energy decreased 0.72-1.2%, corresponding to a change in radiative forcing of 0.008-0.013 W/m². These estimates are for application to the Beaufort Sea or Transpolar Drift.
    • A modeling study by Zampieri and Goessling (2019) showed increased reflected solar radiation in the Arctic during summer of approximately 5.0 W/m² from 2021-2060 and approximately 6.5 W/m² for 2061–2100. In this study, all sea ice north of 66.5°N during winter was thickened.
    • Pumping water on top of ice also has a temporary effect on outgoing longwave radiation (F. Ypma pers. comm.).

• Direct or indirect impact on sea ice?
  • Direct impact on sea ice via thickening and melt reduction.
• New or old ice?
  • Existing ice
    • van Dijke (2022) proposes to thicken first year ice as opposed to multi-year ice. Most newer marginal ice would otherwise be lost from the system, and the albedo modification benefits are the largest for first year ice.
• Impact on sea ice
  • Maintenance of summer sea ice for about 60 yrs, increases in thickness 0.7-1.0 m.
    • A modeling study demonstrated the potential to maintain summer sea ice cover for the next 60 yrs (Zampieri and Goessling 2019). In this study, all sea ice north of 66.5°N during winter was thickened.
    • A conceptual model reported potential increases in sea ice thickness up to 1 m (Desch et al. 2017). A follow-up modeling study estimated increased sea ice thickness of 70 cm with 20 cm of flooding (Pauling and Bitz 2021).
    • If Beaufort Gyre is targeted, ice is likely to remain in the area for 5-6 years. Ice can remain within the Transpolar Drift for 1-2 years (van Dijke 2022).
    • Importantly, the impact on sea ice will depend on what the goal of deployment is, and the scale of deployment. Decreasing the amount of solar radiation in the Arctic will require a large surface area and yearly application to stabilize summer sea ice extent. Increasing the amount of multi-year ice requires additional thickness.

Scalability

• Unknown, depends on goal
  • The plan laid out in Desch et al. (2017) is for 10% of the Arctic Ocean area (100,000,000 km²).
  • Zampieri and Goessling 2019 recommend 10,000,000 pumping devices covering approximately 0.1km² each (10,000 km² total). If warming continues more devices would be required.
  • Arctic Reflections is targeting specific locations within the Arctic Ocean to maximize ice distribution. The goal is to prevent 100,000 km² of melting yearly via 100-1000 sites and stabilize summer sea ice extent.
    • Targeting the Beaufort Gyre may increase ice retention, while the Fram Strait, south of the Transpolar Drift, should be avoided due to the potential for ice export in this region (van Dijke 2022).
  • Real Ice is aiming for 1,000,000 km² of sea ice yearly to preserve current September sea ice extent and possibly restore September sea ice extent to levels from 1980s. They are targeting areas most a risk of summer melt or that could be restored to full-year coverage based on historical patterns and start of winter thickness.
  • Water volumes of 707-1,095 km³ (Beaufort Sea) and 386-464 km³ (Transpolar Drift) are required to avoid annual sea ice loss each year (322 km³ ice volume; 49,200 km² ice area; 83,400 km² ice extent; van Dijke 2022).

• Unknown
  • Some details on efficiency and efficacy of pumping and of flooding snow available in Desch et al. (2017), Pauling and Bitz (2021), and van Dijke (2022).
  • There are many tradeoffs that need to be considered related to timing, natural ice growth cycles, and impact on albedo (F. Ypma pers. comm.).

• Unknown
  • Real Ice and Arctic Reflections have plans to reach full scale in early 2030s.

• Unknown
  • To date studies of this technique have found minimal potential for global impact (Zampieri and Goessling 2019, Pauling and Bitz 2021).

• To be effective this technology would need to happen as soon as possible. As Arctic sea ice area further decreases there be less potential sea ice to apply this technique (Pauling and Bitz 2021). This concern depends on when the approach would be applied, with more ice being available during winter.
• This technique may become technically feasible within 20 years, but deployment and Arctic impact would require achieving scalability, which may not be able to happen within 20 years.

Cost

• $ billions
  • Initial estimate of $500 billion to build 10 million wind-powered pumps to deploy this technology (Desch et al. 2017).
  • Real Ice estimates cost to $43 billion over first 10 years (approximately $6 billion per year once at full scale, re-icing 1,000,000 km²). This cost includes energy production and distribution, production and maintenance of engineering components, and personnel.
  • Arctic Reflections’ cost estimates for focusing on 100,000 km² of ice are $1-10 billion.

• Unknown; potential to use renewable energy
  • Desch et al. (2017) proposed to power the system using wind.
  • Real Ice has proposed powering underwater drones with hydrogen fuel cells. Wind or solar power would be used to create green hydrogen for use with the hydrogen fuel cells. They estimate it will take 8MWh of energy to re-ice 1 km² of sea ice, including the start of winter and end of winter operations.
  • van Dijke (2022) suggests water volumes of 707-1,095 km³ (Beaufort Sea) and 386-464 km³ (Transpolar Drift) are required to avoid annual sea ice loss each year (322 km³ ice volume). The power required to pump this volume of water is 4.5-7.0 GW (Beaufort Sea) and 2.5-3.0 GW (Transpolar Drift).

Impact on

• Variable; increases of 0.39-0.66 for thickening ice and adding snow, increases of 0.33 for prevention of sea ice melt and conversion to open water, potential decrease in albedo of 0.05-0.15 from flooding snow.
  • New ice has an albedo of 0.15 – 0.42 (depending on presence of snow; Webster and Warren 2022). By thickening ice and adding snow, albedo may be increased to 0.81 (Webster and Warren 2022; values reported here are for broadband clear skies, but that paper also provides values for visible and near-infrared albedo).
  • Thickening sea ice allows snow and sea ice to persist longer in summer where open water would otherwise occur, giving rise to an albedo of closer to 0.4 for multiyear ice compared to 0.7 for open water near the sea ice edge (Perovich and Polashenski 2012).
  • Flooding snow far to the north of the ice edge, however, can decrease albedo in the by 0.05-0.15 (Pauling and Bitz 2021).
  • Thickened ice in field and laboratory studies is whiter than natural ice, but it is unknown if that characteristic is maintained over time (van Dijke in review). The whitening of the ice is likely due to difference in salinity between the original ice and the flooded ice or to having more air trapped in the flooded ice layer (van Dijke in review).
  • Impacts will be dependent on time of year. Avoiding open water and postponing ice melt will be most effective in June and July (e.g., postponing open water by 10-30 days in July; F. Ypma pers. comm.).
  • Impacts will also be dependent on melt rate, which varies by region. For example, a modeling study shows that adding 30 cm of thickness corresponds to 1 month of additional ice in the Transpolar Drift area and 2 weeks in the Beaufort Sea (van Dijke in review).

• Global
  • Minimal (0.02°C) to no global cooling effect (Zampieri and Goessling 2019; Pauling and Bitz 2021).
    • In the modeling study by Zampieri and Goessling 2019 all sea ice north of 66.5°N during winter was thickened. In the modeling study by Pauling and Bitz 2021 sea ice covering the entire Arctic Ocean was thickened.
• Arctic region
  • Decreases in temperature in the Arctic of 1.3-2°C, with greatest decreases during summer.
    • A modeling study reported 1.3-1.4°C of cooling in the Arctic (Zampieri and Goessling 2019) during summer, plus warming in winter where pumps are active leading to net cooling in winter of 0.3°C and increases over time to warming of 0.5°C (2061-2100). The warm winter anomalies are due to maintaining a liquid water layer. In this study, all sea ice north of 66.5°N during winter was thickened.
    • A modeling study found up to 2°C cooling in the Arctic (Pauling and Bitz 2021) and noted that the temperature decrease was sensitive to the starting conditions. With less sea ice at the beginning of deployment the temperature decrease is less (Pauling and Bitz 2021). In this study sea ice covering the entire Arctic Ocean was thickened. This study used more realistic physical conditions than Zampieri and Goessling (2019) and did not find winter warming.

• Global
  • Decreases of approximately 0.25 W/m² in July, and 0.02-0.14 W/m² when averaged over the year.
    • A modeling study reports decreases in globally averaged solar radiative forcing from Arctic ice management of approximately 0.25 W/m² in July throughout the model time series (2021-2100). Averaged across the year, the decrease in globally averaged radiative forcing is a lot less, from approximately 0.02 W/m² (2021–2060) to 0.08 W/m² (2061–2100) (Zampieri and Goessling 2019). In this study, all sea ice north of 66.5°N during winter was thickened.
    • Desch et al. (2017) estimated global yearly averaged decline in radiative forcing of 0.14 W/m². In this study sea ice covering the entire Arctic Ocean was thickened.
• Arctic region
  • Decreased absorption of 0.008-6.5 W/m².
    • After 1 year of deployment, van Dijke (2022) estimated in a model that regional absorbed energy decreased 0.72-1.2%, corresponding to a change in radiative forcing of 0.008-0.013 W/m². These estimates are for application to the Beaufort Sea or Transpolar Drift.
    • A modeling study by Zampieri and Goessling (2019) increased reflected solar radiation in the Arctic during summer of approximately 0 W/m² from 2021-2060 and approximately 6.5 W/m² for 2061–2100. In this study, all sea ice north of 66.5°N during winter was thickened.
    • Pumping water on top of ice also has a temporary effect on outgoing longwave radiation (F. Ypma pers. comm.).

• Direct or indirect impact on sea ice?
  • Direct impact on sea ice via thickening and melt reduction.
• New or old ice?
  • Existing ice
    • van Dijke (2022) proposes to thicken first year ice as opposed to multi-year ice. Most newer marginal ice would otherwise be lost from the system, and the albedo modification benefits are the largest for first year ice.
• Impact on sea ice
  • Maintenance of summer sea ice for about 60 yrs, increases in thickness 0.7-1.0 m.
    • A modeling study demonstrated the potential to maintain summer sea ice cover for the next 60 yrs (Zampieri and Goessling 2019). In this study, all sea ice north of 66.5°N during winter was thickened.
    • A conceptual model reported potential increases in sea ice thickness up to 1 m (Desch et al. 2017). A follow-up modeling study estimated increased sea ice thickness of 70 cm with 20 cm of flooding (Pauling and Bitz 2021).
    • If Beaufort Gyre is targeted, ice is likely to remain in the area for 5-6 years. Ice can remain within the Transpolar Drift for 1-2 years (van Dijke 2022).
    • Importantly, the impact on sea ice will depend on what the goal of deployment is, and the scale of deployment. Decreasing the amount of solar radiation in the Arctic will require a large surface area and yearly application to stabilize summer sea ice extent. Increasing the amount of multi-year ice requires additional thickness.

Scalability

• Unknown, depends on goal
  • The plan laid out in Desch et al. (2017) is for 10% of the Arctic Ocean area (100,000,000 km²).
  • Zampieri and Goessling 2019 recommend 10,000,000 pumping devices covering approximately 0.1km² each (10,000 km² total). If warming continues more devices would be required.
  • Arctic Reflections is targeting specific locations within the Arctic Ocean to maximize ice distribution. The goal is to prevent 100,000 km² of melting yearly via 100-1000 sites and stabilize summer sea ice extent.
    • Targeting the Beaufort Gyre may increase ice retention, while the Fram Strait, south of the Transpolar Drift, should be avoided due to the potential for ice export in this region (van Dijke 2022).
  • Real Ice is aiming for 1,000,000 km² of sea ice yearly to preserve current September sea ice extent and possibly restore September sea ice extent to levels from 1980s. They are targeting areas most a risk of summer melt or that could be restored to full-year coverage based on historical patterns and start of winter thickness.
  • Water volumes of 707-1,095 km³ (Beaufort Sea) and 386-464 km³ (Transpolar Drift) are required to avoid annual sea ice loss each year (322 km³ ice volume; 49,200 km² ice area; 83,400 km² ice extent; van Dijke 2022).

• Unknown
  • Some details on efficiency and efficacy of pumping and of flooding snow available in Desch et al. (2017), Pauling and Bitz (2021), and van Dijke (2022).
  • There are many tradeoffs that need to be considered related to timing, natural ice growth cycles, and impact on albedo (F. Ypma pers. comm.).

• Unknown
  • Real Ice and Arctic Reflections have plans to reach full scale in early 2030s.

• Unknown
  • To date studies of this technique have found minimal potential for global impact (Zampieri and Goessling 2019, Pauling and Bitz 2021).

• To be effective this technology would need to happen as soon as possible. As Arctic sea ice area further decreases there be less potential sea ice to apply this technique (Pauling and Bitz 2021). This concern depends on when the approach would be applied, with more ice being available during winter.
• This technique may become technically feasible within 20 years, but deployment and Arctic impact would require achieving scalability, which may not be able to happen within 20 years.

Cost

• $ billions
  • Initial estimate of $500 billion to build 10 million wind-powered pumps to deploy this technology (Desch et al. 2017).
  • Real Ice estimates cost to $43 billion over first 10 years (approximately $6 billion per year once at full scale, re-icing 1,000,000 km²). This cost includes energy production and distribution, production and maintenance of engineering components, and personnel.
  • Arctic Reflections’ cost estimates for focusing on 100,000 km² of ice are $1-10 billion.

• Unknown; potential to use renewable energy
  • Desch et al. (2017) proposed to power the system using wind.
  • Real Ice has proposed powering underwater drones with hydrogen fuel cells. Wind or solar power would be used to create green hydrogen for use with the hydrogen fuel cells. They estimate it will take 8MWh of energy to re-ice 1 km² of sea ice, including the start of winter and end of winter operations.
  • van Dijke (2022) suggests water volumes of 707-1,095 km³ (Beaufort Sea) and 386-464 km³ (Transpolar Drift) are required to avoid annual sea ice loss each year (322 km³ ice volume). The power required to pump this volume of water is 4.5-7.0 GW (Beaufort Sea) and 2.5-3.0 GW (Transpolar Drift).

Impact on

• Variable; increases of 0.39-0.66 for thickening ice and adding snow, increases of 0.33 for prevention of sea ice melt and conversion to open water, potential decrease in albedo of 0.05-0.15 from flooding snow.
  • New ice has an albedo of 0.15 – 0.42 (depending on presence of snow; Webster and Warren 2022). By thickening ice and adding snow, albedo may be increased to 0.81 (Webster and Warren 2022; values reported here are for broadband clear skies, but that paper also provides values for visible and near-infrared albedo).
  • Thickening sea ice allows snow and sea ice to persist longer in summer where open water would otherwise occur, giving rise to an albedo of closer to 0.4 for multiyear ice compared to 0.7 for open water near the sea ice edge (Perovich and Polashenski 2012).
  • Flooding snow far to the north of the ice edge, however, can decrease albedo in the by 0.05-0.15 (Pauling and Bitz 2021).
  • Thickened ice in field and laboratory studies is whiter than natural ice, but it is unknown if that characteristic is maintained over time (van Dijke in review). The whitening of the ice is likely due to difference in salinity between the original ice and the flooded ice or to having more air trapped in the flooded ice layer (van Dijke in review).
  • Impacts will be dependent on time of year. Avoiding open water and postponing ice melt will be most effective in June and July (e.g., postponing open water by 10-30 days in July; F. Ypma pers. comm.).
  • Impacts will also be dependent on melt rate, which varies by region. For example, a modeling study shows that adding 30 cm of thickness corresponds to 1 month of additional ice in the Transpolar Drift area and 2 weeks in the Beaufort Sea (van Dijke in review).

• Global
  • Minimal (0.02°C) to no global cooling effect (Zampieri and Goessling 2019; Pauling and Bitz 2021).
    • In the modeling study by Zampieri and Goessling 2019 all sea ice north of 66.5°N during winter was thickened. In the modeling study by Pauling and Bitz 2021sea ice covering the entire Arctic Ocean was thickened.
• Arctic region
  • Decreases in temperature in the Arctic of 1.3-2°C, with greatest decreases during summer.
    • A modeling study reported 1.3-1.4°C of cooling in the Arctic (Zampieri and Goessling 2019) during summer, plus warming in winter where pumps are active leading to net cooling in winter of 0.3°C and increases over time to warming of 0.5°C (2061-2100). The warm winter anomalies are due to maintaining a liquid water layer. In this study, all sea ice north of 66.5°N during winter was thickened.
    • A modeling study found up to 2°C cooling in the Arctic (Pauling and Bitz 2021) and noted that the temperature decrease was sensitive to the starting conditions. With less sea ice at the beginning of deployment the temperature decrease is less (Pauling and Bitz 2021). In this study sea ice covering the entire Arctic Ocean was thickened. This study used more realistic physical conditions than Zampieri and Goessling (2019) and did not find winter warming.

• Global
  • Decreases of approximately 0.25 W/m² in July, and 0.02-0.14 W/m² when averaged over the year.
    • A modeling study reports decreases in globally averaged solar radiative forcing from Arctic ice management of approximately 0.25 W/m² in July throughout the model time series (2021-2100). Averaged across the year, the decrease in globally averaged radiative forcing is a lot less, from approximately 0.02 W/m² (2021–2060) to 0.08 W/m² (2061–2100) (Zampieri and Goessling 2019). In this study, all sea ice north of 66.5°N during winter was thickened.
    • Desch et al. (2017) estimated global yearly averaged decline in radiative forcing of 0.14 W/m². In this study sea ice covering the entire Arctic Ocean was thickened.
• Arctic region
  • Decreased absorption of 0.008-6.5 W/m².
    • After 1 year of deployment, van Dijke (2022) estimated in a model that regional absorbed energy decreased 0.72-1.2%, corresponding to a change in radiative forcing of 0.008-0.013 W/m². These estimates are for application to the Beaufort Sea or Transpolar Drift.
    • A modeling study by Zampieri and Goessling (2019) increased reflected solar radiation in the Arctic during summer of approximately 0 W/m² from 2021-2060 and approximately 6.5 W/m² for 2061–2100. In this study, all sea ice north of 66.5°N during winter was thickened.
    • Pumping water on top of ice also has a temporary effect on outgoing longwave radiation (F. Ypma pers. comm.).

• Direct or indirect impact on sea ice?
  • Direct impact on sea ice via thickening and melt reduction.
• New or old ice?
  • Existing ice
    • van Dijke (2022) proposes to thicken first year ice as opposed to multi-year ice. Most newer marginal ice would otherwise be lost from the system, and the albedo modification benefits are the largest for first year ice.
• Impact on sea ice
  • Maintenance of summer sea ice for about 60 yrs, increases in thickness 0.7-1.0 m.
    • A modeling study demonstrated the potential to maintain summer sea ice cover for the next 60 yrs (Zampieri and Goessling 2019). In this study, all sea ice north of 66.5°N during winter was thickened.
    • A conceptual model reported potential increases in sea ice thickness up to 1 m (Desch et al. 2017). A follow-up modeling study estimated increased sea ice thickness of 70 cm with 20 cm of flooding (Pauling and Bitz 2021).
    • If Beaufort Gyre is targeted, ice is likely to remain in the area for 5-6 years. Ice can remain within the Transpolar Drift for 1-2 years (van Dijke 2022).
    • Importantly, the impact on sea ice will depend on what the goal of deployment is, and the scale of deployment. Decreasing the amount of solar radiation in the Arctic will require a large surface area and yearly application to stabilize summer sea ice extent. Increasing the amount of multi-year ice requires additional thickness.

Scalability

• Unknown, depends on goal
  • The plan laid out in Desch et al. (2017) is for 10% of the Arctic Ocean area (100,000,000 km²).
  • Zampieri and Goessling 2019 recommend 10,000,000 pumping devices covering approximately 0.1km² each (10,000 km² total). If warming continues more devices would be required.
  • Arctic Reflections is targeting specific locations within the Arctic Ocean to maximize ice distribution. The goal is to prevent 100,000 km² of melting yearly via 100-1000 sites and stabilize summer sea ice extent.
    • Targeting the Beaufort Gyre may increase ice retention, while the Fram Strait, south of the Transpolar Drift, should be avoided due to the potential for ice export in this region (van Dijke 2022).
  • Real Ice is aiming for 1,000,000 km² of sea ice yearly to preserve current September sea ice extent and possibly restore September sea ice extent to levels from 1980s. They are targeting areas most a risk of summer melt or that could be restored to full-year coverage based on historical patterns and start of winter thickness.
  • Water volumes of 707-1,095 km³ (Beaufort Sea) and 386-464 km³ (Transpolar Drift) are required to avoid annual sea ice loss each year (322 km³ ice volume; 49,200 km² ice area; 83,400 km² ice extent; van Dijke 2022).

• Unknown
  • Some details on efficiency and efficacy of pumping and of flooding snow available in Desch et al. (2017), Pauling and Bitz (2021), and van Dijke (2022).
  • There are many tradeoffs that need to be considered related to timing, natural ice growth cycles, and impact on albedo (F. Ypma pers. comm.).

• Unknown
  • Real Ice and Arctic Reflections have plans to reach full scale in early 2030s.

• Unknown
  • To date studies of this technique have found minimal potential for global impact (Zampieri and Goessling 2019, Pauling and Bitz 2021).

• To be effective this technology would need to happen as soon as possible. As Arctic sea ice area further decreases there be less potential sea ice to apply this technique (Pauling and Bitz 2021). This concern depends on when the approach would be applied, with more ice being available during winter.
• This technique may become technically feasible within 20 years, but deployment and Arctic impact would require achieving scalability, which may not be able to happen within 20 years.

Cost

• $ billions
  • Initial estimate of $500 billion to build 10 million wind-powered pumps to deploy this technology (Desch et al. 2017).
  • Real Ice estimates cost to $43 billion over first 10 years (approximately $6 billion per year once at full scale, re-icing 1,000,000 km²). This cost includes energy production and distribution, production and maintenance of engineering components, and personnel.
  • Arctic Reflections’ cost estimates for focusing on 100,000 km² of ice are $1-10 billion.

• Unknown; potential to use renewable energy
  • Desch et al. (2017) proposed to power the system using wind.
  • Real Ice has proposed powering underwater drones with hydrogen fuel cells. Wind or solar power would be used to create green hydrogen for use with the hydrogen fuel cells. They estimate it will take 8MWh of energy to re-ice 1 km² of sea ice, including the start of winter and end of winter operations.
  • van Dijke (2022) suggests water volumes of 707-1,095 km³ (Beaufort Sea) and 386-464 km³ (Transpolar Drift) are required to avoid annual sea ice loss each year (322 km³ ice volume). The power required to pump this volume of water is 4.5-7.0 GW (Beaufort Sea) and 2.5-3.0 GW (Transpolar Drift).

Impact on

• Variable; increases of 0.39-0.66 for thickening ice and adding snow, increases of 0.33 for prevention of sea ice melt and conversion to open water, potential decrease in albedo of 0.05-0.15 from flooding snow.
  • New ice has an albedo of 0.15 – 0.42 (depending on presence of snow; Webster and Warren 2022). By thickening ice and adding snow, albedo may be increased to 0.81 (Webster and Warren 2022; values reported here are for broadband clear skies, but that paper also provides values for visible and near-infrared albedo).
  • Thickening sea ice allows snow and sea ice to persist longer in summer where open water would otherwise occur, giving rise to an albedo of closer to 0.4 for multiyear ice compared to 0.7 for open water near the sea ice edge (Perovich and Polashenski 2012).
  • Flooding snow far to the north of the ice edge, however, can decrease albedo in the by 0.05-0.15 (Pauling and Bitz 2021).
  • Thickened ice in field and laboratory studies is whiter than natural ice, but it is unknown if that characteristic is maintained over time (van Dijke in review). The whitening of the ice is likely due to difference in salinity between the original ice and the flooded ice or to having more air trapped in the flooded ice layer (van Dijke in review).
  • Impacts will be dependent on time of year. Avoiding open water and postponing ice melt will be most effective in June and July (e.g., postponing open water by 10-30 days in July; F. Ypma pers. comm.).
  • Impacts will also be dependent on melt rate, which varies by region. For example, a modeling study shows that adding 30 cm of thickness corresponds to 1 month of additional ice in the Transpolar Drift area and 2 weeks in the Beaufort Sea (van Dijke in review).

• Global
  • Minimal (0.02°C) to no global cooling effect (Zampieri and Goessling 2019; Pauling and Bitz 2021).
    • In the modeling study by Zampieri and Goessling 2019 all sea ice north of 66.5°N during winter was thickened. In the modeling study by Pauling and Bitz 2021sea ice covering the entire Arctic Ocean was thickened.
• Arctic region
  • Decreases in temperature in the Arctic of 1.3-2°C, with greatest decreases during summer.
    • Modeling study reported 1.3-1.4°C of cooling in the Arctic (Zampieri and Goessling 2019) during summer, plus warming in winter where pumps are active leading to net cooling in winter of 0.3°C and increases over time to warming of 0.5°C (2061-2100). The warm winter anomalies are due to maintaining a liquid water layer. In this study, all sea ice north of 66.5°N during winter was thickened.
    • Modeling study found up to 2°C cooling in the Arctic (Pauling and Bitz 2021) and noted that the temperature decrease was sensitive to the starting conditions. With less sea ice at the beginning of deployment the temperature decrease is less (Pauling and Bitz 2021). In this study sea ice covering the entire Arctic Ocean was thickened. This study used more realistic physical conditions than Zampieri and Goessling (2019) and did not find winter warming.

• Global
  • Decreases of approximately 0.25 W/m² in July, and 0.02-0.14 W/m² when averaged over the year.
    • Modeling study reports decreases in globally averaged solar radiative forcing from Arctic ice management of approximately 0.25 W/m² in July throughout the model time series (2021-2100). Averaged across the year, the decrease in globally averaged radiative forcing is a lot less, from approximately 0.02 W/m² (2021–2060) to 0.08 W/m² (2061–2100) (Zampieri and Goessling 2019). In this study, all sea ice north of 66.5°N during winter was thickened.
    • Desch et al. (2017) estimated global yearly averaged decline in radiative forcing of 0.14 W/m². In this study sea ice covering the entire Arctic Ocean was thickened.
• Arctic region
  • Decreased absorption of 0.008-6.5 W/m²
    • After 1 year of deployment, van Dijke (2022) estimated in a model that regional absorbed energy decreased 0.72-1.2%, corresponding to a change in radiative forcing of 0.008-0.013 W/m². These estimates are for application to the Beaufort Sea or Transpolar Drift.
    • Modeling study by Zampieri and Goessling (2019) increased reflected solar radiation in the Arctic during summer of approximately 0 W/m² from 2021-2060 and approximately 6.5 W/m² for 2061–2100. In this study, all sea ice north of 66.5°N during winter was thickened.
    • Pumping water on top of ice also has a temporary effect on outgoing longwave radiation (F. Ypma pers. comm.).

• Direct or indirect impact on sea ice?
  • Direct impact on sea ice via thickening and melt reduction
• New or old ice?
  • Existing ice
    • van Dijke (2022) proposes to thicken first year ice as opposed to multi-year ice. Most newer marginal ice would otherwise be lost from the system, and the albedo modification benefits are the largest for first year ice.
• Impact on sea ice
  • Maintenance of summer sea ice for about 60 yrs, increases in thickness 0.7-1 m.
    • Modeling study demonstrated potential to maintain summer sea ice cover for next 60 yrs (Zampieri and Goessling 2019). In this study, all sea ice north of 66.5°N during winter was thickened.
    • Conceptual model reported potential increases of sea ice thickness up to 1 m (Desch et al. 2017). A follow up modeling study estimated increased sea ice thickness of 70 cm with 20 cm of flooding (Pauling and Bitz 2021).
    • If target Beaufort Gyre, ice likely to remain in area for 5-6 years. Ice can remain within the Transpolar Drift 1-2 years (van Dijke 2022).
    • Importantly, the impact on sea ice will depend on what the goal of deployment is, and the scale of deployment. Decreasing the amount of solar radiation in the Arctic will require a large surface area and yearly application to stabilize summer sea ice extent. Increasing the amount of multi-year ice requires additional thickness.

Scalability

• Unknown, depends on goal
  • The plan laid out in Desch et al. (2017) is for 10% of the Arctic Ocean area (100,000,000 km²).
  • Zampieri and Goessling 2019 recommend 10,000,000 pumping devices covering approximately 0.1km² each (10,000 km² total). If warming continues more devices would be required.
  • Arctic Reflections is targeting specific locations within the Arctic Ocean to maximize ice distribution. The goal is to prevent 100,000 km² of melting yearly via 100-1000 sites and stabilize summer sea ice extent.
    • Targeting the Beaufort Gyre may increase ice retention, while the Fram Strait, south of the Transpolar Drift, should be avoided due to the potential for ice export in this region (van Dijke 2022).
  • Real Ice is aiming for 1,000,000 km² of sea ice yearly to preserve current September sea ice extent and possibly restore September sea ice extent to levels from 1980s. They are targeting areas most a risk of summer melt or that could be restored to full-year coverage based on historical patterns and start of winter thickness.
  • Water volumes of 707-1,095 km³ (Beaufort Sea) and 386-464 km³ (Transpolar Drift) are required to avoid annual sea ice loss each year (322 km³ ice volume; 49,200 km² ice area; 83,400 km² ice extent; van Dijke 2022).

• Unknown
  • Some details on efficiency and efficacy of pumping and of flooding snow available in Desch et al. (2017), Pauling and Bitz (2021), and van Dijke (2022).
  • There are many tradeoffs that need to be considered related to timing, natural ice growth cycles, and impact on albedo (F. Ypma pers. comm.).

• Unknown
  • Real Ice and Arctic Reflections have plans to reach full scale in early 2030s.

• Unknown
  • To date studies of this technique have found minimal potential for global impact (Zampieri and Goessling 2019, Pauling and Bitz 2021).

• To be effective this technology would need to happen as soon as possible. As Arctic sea ice area further decreases there be less potential sea ice to apply this technique (Pauling and Bitz 2021). This concern depends on when the approach would be applied, with more ice being available during winter.
• This technique may become technically feasible within 20 years, but deployment and Arctic impact would require achieving scalability, which may not be able to happen within 20 years.

Cost

• $ billions
  • Initial estimate of $500 billion to build 10 million wind-powered pumps to deploy this technology (Desch et al. 2017).
  • Real Ice estimates cost to $43 billion over first 10 years (approximately $6 billion per year once at full scale, re-icing 1,000,000 km²). This cost includes energy production and distribution, production and maintenance of engineering components, and personnel.
  • Arctic Reflections’ cost estimates for focusing on 100,000 km² of ice are $1-10 billion.

• Unknown; potential to use renewable energy
  • Desch et al. (2017) proposed to power the system using wind.
  • Real Ice has proposed powering underwater drones with hydrogen fuel cells. Wind or solar power would be used to create green hydrogen for use with the hydrogen fuel cells. They estimate it will take 8MWh of energy to re-ice 1 km² of sea ice, including the start of winter and end of winter operations.
  • van Dijke (2022) suggests water volumes of 707-1,095 km³ (Beaufort Sea) and 386-464 km³ (Transpolar Drift) are required to avoid annual sea ice loss each year (322 km³ ice volume). The power required to pump this volume of water is 4.5-7.0 GW (Beaufort Sea) and 2.5-3.0 GW (Transpolar Drift).

Impact on

• Variable; increases of 0.39-0.66 for thickening ice and adding snow, increases of 0.33 for prevention of sea ice melt and conversion to open water, potential decrease in albedo of 0.05-0.15 from flooding snow.
  • New ice has an albedo of 0.15 – 0.42 (depending on presence of snow; Webster and Warren 2022). By thickening ice and adding snow, albedo may be increased to 0.81 (Webster and Warren 2022; values reported here are for broadband clear skies, but that paper also provides values for visible and near-infrared albedo)
  • Thickening sea ice allows snow and sea ice to persist longer in summer where open water would otherwise occur, giving rise to an albedo of closer to 0.4 for multiyear ice compared to 0.7 for open water near the sea ice edge (Perovich and Polashenski 2012).
  • Flooding snow far to the north of the ice edge, however, can decrease albedo in the by 0.05-0.15 (Pauling and Bitz 2021).
  • Thickened ice in field and laboratory studies is whiter than natural ice, but it is unknown if that characteristic is maintained over time (van Dijke in review). The whitening of the ice is likely due to difference in salinity between the original ice and the flooded ice or to having more air trapped in the flooded ice layer (van Dijke in review).
  • Impacts will be dependent on time of year. Avoiding open water and postponing ice melt will be most effective in June and July (e.g., postponing open water by 10-30 days in July; F. Ypma pers. comm.).
  • Impacts will also be dependent on melt rate, which varies by region. For example, a modeling study shows that adding 30 cm of thickness corresponds to 1 month of additional ice in the Transpolar Drift area and 2 weeks in the Beaufort Sea (van Dijke in review).

• Global
  • Minimal (0.02°C) to no global cooling effect (Zampieri and Goessling 2019; Pauling and Bitz 2021).
    • In the modeling study by Zampieri and Goessling 2019 all sea ice north of 66.5°N during winter was thickened. In the modeling study by Pauling and Bitz 2021sea ice covering the entire Arctic Ocean was thickened.
• Arctic region
  • Decreases in temperature in the Arctic of 1.3-2°C, with greatest decreases during summer.
    • Modeling study reported 1.3-1.4°C of cooling in the Arctic (Zampieri and Goessling 2019) during summer, plus warming in winter where pumps are active leading to net cooling in winter of 0.3°C and increases over time to warming of 0.5°C (2061-2100). The warm winter anomalies are due to maintaining a liquid water layer. In this study, all sea ice north of 66.5°N during winter was thickened.
    • Modeling study found up to 2°C cooling in the Arctic (Pauling and Bitz 2021) and noted that the temperature decrease was sensitive to the starting conditions. With less sea ice at the beginning of deployment the temperature decrease is less (Pauling and Bitz 2021). In this study sea ice covering the entire Arctic Ocean was thickened. This study used more realistic physical conditions than Zampieri and Goessling (2019) and did not find winter warming.

• Global
  • Decreases of approximately 0.25 W/m² in July, and 0.02-0.14 W/m² when averaged over the year.
    • Modeling study reports decreases in globally averaged solar radiative forcing from Arctic ice management of approximately 0.25 W/m² in July throughout the model time series (2021-2100). Averaged across the year, the decrease in globally averaged radiative forcing is a lot less, from approximately 0.02 W/m² (2021–2060) to 0.08 W/m² (2061–2100) (Zampieri and Goessling 2019). In this study, all sea ice north of 66.5°N during winter was thickened.
    • Desch et al. (2017) estimated global yearly averaged decline in radiative forcing of 0.14 W/m². In this study sea ice covering the entire Arctic Ocean was thickened.
• Arctic region
  • Decreased absorption of 0.008-6.5 W/m²
    • After 1 year of deployment, van Dijke (2022) estimated in a model that regional absorbed energy decreased 0.72-1.2%, corresponding to a change in radiative forcing of 0.008-0.013 W/m². These estimates are for application to the Beaufort Sea or Transpolar Drift.
    • Modeling study by Zampieri and Goessling (2019) increased reflected solar radiation in the Arctic during summer of approximately 0 W/m² from 2021-2060 and approximately 6.5 W/m² for 2061–2100. In this study, all sea ice north of 66.5°N during winter was thickened.
    • Pumping water on top of ice also has a temporary effect on outgoing longwave radiation (F. Ypma pers. comm.).

• Direct or indirect impact on sea ice?
  • Direct impact on sea ice via thickening and melt reduction
• New or old ice?
  • Existing ice
    • van Dijke (2022) proposes to thicken first year ice as opposed to multi-year ice. Most newer marginal ice would otherwise be lost from the system, and the albedo modification benefits are the largest for first year ice.
• Impact on sea ice
  • Maintenance of summer sea ice for about 60 yrs, increases in thickness 0.7-1 m.
    • Modeling study demonstrated potential to maintain summer sea ice cover for next 60 yrs (Zampieri and Goessling 2019). In this study, all sea ice north of 66.5°N during winter was thickened.
    • Conceptual model reported potential increases of sea ice thickness up to 1 m (Desch et al. 2017). A follow up modeling study estimated increased sea ice thickness of 70 cm with 20 cm of flooding (Pauling and Bitz 2021).
    • If target Beaufort Gyre, ice likely to remain in area for 5-6 years. Ice can remain within the Transpolar Drift 1-2 years (van Dijke 2022).
    • Importantly, the impact on sea ice will depend on what the goal of deployment is, and the scale of deployment. Decreasing the amount of solar radiation in the Arctic will require a large surface area and yearly application to stabilize summer sea ice extent. Increasing the amount of multi-year ice requires additional thickness.

Scalability

• Unknown, depends on goal
  • The plan laid out in Desch et al. (2017) is for 10% of the Arctic Ocean area (100,000,000 km²).
  • Zampieri and Goessling 2019 recommend 10,000,000 pumping devices covering approximately 0.1km² each (10,000 km² total). If warming continues more devices would be required.
  • Arctic Reflections is targeting specific locations within the Arctic Ocean to maximize ice distribution. The goal is to prevent 100,000 km² of melting yearly via 100-1000 sites and stabilize summer sea ice extent.
    • Targeting the Beaufort Gyre may increase ice retention, while the Fram Strait, south of the Transpolar Drift, should be avoided due to the potential for ice export in this region (van Dijke 2022).
  • Real Ice is aiming for 1,000,000 km² of sea ice yearly to preserve current September sea ice extent and possibly restore September sea ice extent to levels from 1980s. They are targeting areas most a risk of summer melt or that could be restored to full-year coverage based on historical patterns and start of winter thickness.
  • Water volumes of 707-1,095 km³ (Beaufort Sea) and 386-464 km³ (Transpolar Drift) are required to avoid annual sea ice loss each year (322 km³ ice volume; 49,200 km² ice area; 83,400 km² ice extent; van Dijke 2022).

• Unknown
  • Some details on efficiency and efficacy of pumping and of flooding snow available in Desch et al. (2017), Pauling and Bitz (2021), and van Dijke (2022)
  • There are many tradeoffs that need to be considered related to timing, natural ice growth cycles, and impact on albedo (F. Ypma pers. comm.).

• Unknown
  • Real Ice and Arctic Reflections have plans to reach full scale in early 2030s.

• Unknown
  • To date studies of this technique have found minimal potential for global impact (Zampieri and Goessling 2019; Pauling and Bitz 2021).

• To be effective this technology would need to happen as soon as possible. As Arctic sea ice area further decreases there be less potential sea ice to apply this technique (Pauling and Bitz 2021). This concern depends on when the approach would be applied, with more ice being available during winter.
• This technique may become technically feasible within 20 years, but deployment and Arctic impact would require achieving scalability, which may not be able to happen within 20 years.

Cost

• $ billions
  • Initial estimate of $500 billion to build 10 million wind-powered pumps to deploy this technology (Desch et al. 2017).
  • Real Ice estimates cost to $43 billion over first 10 years (approximately $6 billion per year once at full scale, re-icing 1,000,000 km²). This cost includes energy production and distribution, production and maintenance of engineering components, and personnel.
  • Arctic Reflections’ cost estimates for focusing on 100,000 km² of ice are $1-10 billion.

• Unknown; potential to use renewable energy
  • Desch et al. (2017) proposed to power the system using wind.
  • Real Ice has proposed powering underwater drones with hydrogen fuel cells. Wind or solar power would be used to create green hydrogen for use with the hydrogen fuel cells. They estimate it will take 8MWh of energy to re-ice 1 km² of sea ice, including the start of winter and end of winter operations.
  • van Dijke (2022) suggests water volumes of 707-1,095 km³ (Beaufort Sea) and 386-464 km³ (Transpolar Drift) are required to avoid annual sea ice loss each year (322 km³ ice volume). The power required to pump this volume of water is 4.5-7.0 GW (Beaufort Sea) and 2.5-3.0 GW (Transpolar Drift).

Impact on

• Variable; increases of 0.39-0.66 for thickening ice and adding snow, increases of 0.33 for prevention of sea ice melt and conversion to open water, potential decrease in albedo of 0.05-0.15 from flooding snow.
  • New ice has an albedo of 0.15 – 0.42 (depending on presence of snow; Webster and Warren 2022). By thickening ice and adding snow, albedo may be increased to 0.81 (Webster and Warren 2022; values reported here are for broadband clear skies, but that paper also provides values for visible and near-infrared albedo)
  • Thickening sea ice allows snow and sea ice to persist longer in summer where open water would otherwise occur, giving rise to an albedo of closer to 0.4 for multiyear ice compared to 0.7 for open water near the sea ice edge (Perovich and Polashenski 2012).
  • Flooding snow far to the north of the ice edge, however, can decrease albedo in the by 0.05-0.15 (Pauling and Bitz 2021).
  • Thickened ice in field and laboratory studies is whiter than natural ice, but it is unknown if that characteristic is maintained over time (van Dijke in review). The whitening of the ice is likely due to difference in salinity between the original ice and the flooded ice or to having more air trapped in the flooded ice layer (van Dijke in review).
  • Impacts will be dependent on time of year. Avoiding open water and postponing ice melt will be most effective in June and July (e.g., postponing open water by 10-30 days in July; F. Ypma pers. comm.).
  • Impacts will also be dependent on melt rate, which varies by region. For example, a modeling study shows that adding 30 cm of thickness corresponds to 1 month of additional ice in the Transpolar Drift area and 2 weeks in the Beaufort Sea (van Dijke in review).

• Global
  • Minimal (0.02°C) to no global cooling effect (Zampieri and Goessling 2019; Pauling and Bitz 2021).
    • In the modeling study by Zampieri and Goessling 2019 all sea ice north of 66.5°N during winter was thickened. In the modeling study by Pauling and Bitz 2021sea ice covering the entire Arctic Ocean was thickened.
• Arctic region
  • Decreases in temperature in the Arctic of 1.3-2°C, with greatest decreases during summer.
    • Modeling study reported 1.3-1.4°C of cooling in the Arctic (Zampieri and Goessling 2019) during summer, plus warming in winter where pumps are active leading to net cooling in winter of 0.3°C and increases over time to warming of 0.5°C (2061-2100). The warm winter anomalies are due to maintaining a liquid water layer. In this study, all sea ice north of 66.5°N during winter was thickened.
    • Modeling study found up to 2°C cooling in the Arctic (Pauling and Bitz 2021) and noted that the temperature decrease was sensitive to the starting conditions. With less sea ice at the beginning of deployment the temperature decrease is less (Pauling and Bitz 2021). In this study sea ice covering the entire Arctic Ocean was thickened. This study used more realistic physical conditions than Zampieri and Goessling (2019) and did not find winter warming.

• Global
  • Decreases of approximately 0.25 W/m² in July, and 0.02-0.14 W/m² when averaged over the year.
    • Modeling study reports decreases in globally averaged solar radiative forcing from Arctic ice management of approximately 0.25 W/m² in July throughout the model time series (2021-2100). Averaged across the year, the decrease in globally averaged radiative forcing is a lot less, from approximately 0.02 W/m² (2021–2060) to 0.08 W/m² (2061–2100) (Zampieri and Goessling 2019). In this study, all sea ice north of 66.5°N during winter was thickened.
    • Desch et al. (2017) estimated global yearly averaged decline in radiative forcing of 0.14 W/m². In this study sea ice covering the entire Arctic Ocean was thickened.
• Arctic region
  • Decreased absorption of 0.008-6.5 W/m²
    • After 1 year of deployment, van Dijke (2022) estimated in a model that regional absorbed energy decreased 0.72-1.2%, corresponding to a change in radiative forcing of 0.008-0.013 W/m². These estimates are for application to the Beaufort Sea or Transpolar Drift.
    • Modeling study by Zampieri and Goessling (2019) increased reflected solar radiation in the Arctic during summer of approximately 0 W/m² from 2021-2060 and approximately 6.5 W/m² for 2061–2100. In this study, all sea ice north of 66.5°N during winter was thickened.
    • Pumping water on top of ice also has a temporary effect on outgoing longwave radiation (F. Ypma pers. comm.).

• Direct or indirect impact on sea ice?
  • Direct impact on sea ice via thickening and melt reduction
• New or old ice?
  • Existing ice
    • van Dijke (2022) proposes to thicken first year ice as opposed to multi-year ice. Most newer marginal ice would otherwise be lost from the system, and the albedo modification benefits are the largest for first year ice.
• Impact on sea ice
  • Maintenance of summer sea ice for about 60 yrs, increases in thickness 0.7-1 m.
    • Modeling study demonstrated potential to maintain summer sea ice cover for next 60 yrs (Zampieri and Goessling 2019). In this study, all sea ice north of 66.5°N during winter was thickened.
    • Conceptual model reported potential increases of sea ice thickness up to 1 m (Desch et al. 2017). A follow up modeling study estimated increased sea ice thickness of 70 cm with 20 cm of flooding (Pauling and Bitz 2021).
    • If target Beaufort Gyre, ice likely to remain in area for 5-6 years. Ice can remain within the Transpolar Drift 1-2 years (van Dijke 2022).
    • Importantly, the impact on sea ice will depend on what the goal of deployment is, and the scale of deployment. Decreasing the amount of solar radiation in the Arctic will require a large surface area and yearly application to stabilize summer sea ice extent. Increasing the amount of multi-year ice requires additional thickness.

Scalability

• Unknown, depends on goal
  • The plan laid out in Desch et al. (2017) is for 10% of the Arctic Ocean area (100,000,000 km²).
  • Zampieri and Goessling 2019 recommend 10,000,000 pumping devices covering approximately 0.1km² each (10,000 km² total). If warming continues more devices would be required.
  • Arctic Reflections is targeting specific locations within the Arctic Ocean to maximize ice distribution. The goal is to prevent 100,000 km² of melting yearly via 100-1000 sites and stabilize summer sea ice extent.
    • Targeting the Beaufort Gyre may increase ice retention, while the Fram Strait, south of the Transpolar Drift, should be avoided due to the potential for ice export in this region (van Dijke 2022).
  • Real Ice is aiming for 1,000,000 km² of sea ice yearly to preserve current September sea ice extent and possibly restore September sea ice extent to levels from 1980s. They are targeting areas most a risk of summer melt or that could be restored to full-year coverage based on historical patterns and start of winter thickness.
  • Water volumes of 707-1,095 km³ (Beaufort Sea) and 386-464 km³ (Transpolar Drift) are required to avoid annual sea ice loss each year (322 km³ ice volume; 49,200 km² ice area; 83,400 km² ice extent; van Dijke 2022).

• Unknown
  • Some details on efficiency and efficacy of pumping and of flooding snow available in Desch et al. (2017), Pauling and Bitz (2021), and van Dijke (2022)
  • There are many tradeoffs that need to be considered related to timing, natural ice growth cycles, and impact on albedo (F. Ypma pers. comm.).

• Unknown
  • Real Ice and Arctic Reflections have plans to reach full scale in early 2030s.

• Unknown
  • To date studies of this technique have found minimal potential for global impact (Zampieri and Goessling 2019; Pauling and Bitz 2021).

• To be effective this technology would need to happen as soon as possible. As Arctic sea ice area further decreases there be less potential sea ice to apply this technique (Pauling and Bitz 2021). This concern depends on when the approach would be applied, with more ice being available during winter.
• This technique may become technically feasible within 20 years, but deployment and Arctic impact would require achieving scalability, which may not be able to happen within 20 years.

Cost

• $ billions
  • Initial estimate of $500 billion to build 10 million wind-powered pumps to deploy this technology (Desch et al. 2017).
  • Real Ice estimates cost to $43 billion over first 10 years (approximately $6 billion per year once at full scale, re-icing 1,000,000 km²). This cost includes energy production and distribution, production and maintenance of engineering components, and personnel.
  • Arctic Reflections’ cost estimates for focusing on 100,000 km² of ice are $1-10 billion.

• Unknown; potential to use renewable energy
  • Desch et al. (2017) proposed to power the system using wind.
  • Real Ice has proposed powering underwater drones with hydrogen fuel cells. Wind or solar power would be used to create green hydrogen for use with the hydrogen fuel cells. They estimate it will take 8MWh of energy to re-ice 1 km² of sea ice, including the start of winter and end of winter operations.
  • van Dijke (2022) suggests water volumes of 707-1,095 km³ (Beaufort Sea) and 386-464 km³ (Transpolar Drift) are required to avoid annual sea ice loss each year (322 km³ ice volume). The power required to pump this volume of water is 4.5-7.0 GW (Beaufort Sea) and 2.5-3.0 GW (Transpolar Drift).

Impact on

• Variable; increases of 0.39-0.66 for thickening ice and adding snow, increases of 0.33 for prevention of sea ice melt and conversion to open water, potential decrease in albedo of 0.05-0.15 from flooding snow.
  • New ice has an albedo of 0.15 – 0.42 (depending on presence of snow; Webster and Warren 2022). By thickening ice and adding snow, albedo may be increased to 0.81 (Webster and Warren 2022; values reported here are for broadband clear skies, but that paper also provides values for visible and near-infrared albedo)
  • Thickening sea ice allows snow and sea ice to persist longer in summer where open water would otherwise occur, giving rise to an albedo of closer to 0.4 for multiyear ice compared to 0.7 for open water near the sea ice edge (Perovich and Polashenski 2012).
  • Flooding snow far to the north of the ice edge, however, can decrease albedo in the by 0.05-0.15 (Pauling and Bitz 2021).
  • Thickened ice in field and laboratory studies is whiter than natural ice, but it is unknown if that characteristic is maintained over time (van Dijke in review). The whitening of the ice is likely due to difference in salinity between the original ice and the flooded ice or to having more air trapped in the flooded ice layer (van Dijke in review).
  • Impacts will be dependent on time of year. Avoiding open water and postponing ice melt will be most effective in June and July (e.g., postponing open water by 10-30 days in July; F. Ypma pers. comm.).
  • Impacts will also be dependent on melt rate, which varies by region. For example, a modeling study shows that adding 30 cm of thickness corresponds to 1 month of additional ice in the Transpolar Drift area and 2 weeks in the Beaufort Sea (van Dijke in review).

• Global
  • Minimal (0.02°C) to no global cooling effect (Zampieri and Goessling 2019; Pauling and Bitz 2021).
    • In the modeling study by Zampieri and Goessling 2019 all sea ice north of 66.5°N during winter was thickened. In the modeling study by Pauling and Bitz 2021sea ice covering the entire Arctic Ocean was thickened.
• Arctic region
  • Decreases in temperature in the Arctic of 1.3-2°C, with greatest decreases during summer.
    • Modeling study reported 1.3-1.4°C of cooling in the Arctic (Zampieri and Goessling 2019) during summer, plus warming in winter where pumps are active leading to net cooling in winter of 0.3°C and increases over time to warming of 0.5°C (2061-2100). The warm winter anomalies are due to maintaining a liquid water layer. In this study, all sea ice north of 66.5°N during winter was thickened.
    • Modeling study found up to 2°C cooling in the Arctic (Pauling and Bitz 2021) and noted that the temperature decrease was sensitive to the starting conditions. With less sea ice at the beginning of deployment the temperature decrease is less (Pauling and Bitz 2021). In this study sea ice covering the entire Arctic Ocean was thickened. This study used more realistic physical conditions than Zampieri and Goessling (2019) and did not find winter warming.

• Global
  • Decreases of approximately 0.25 W/m² in July, and 0.02-0.14 W/m² when averaged over the year.
    • Modeling study reports decreases in globally averaged solar radiative forcing from Arctic ice management of approximately 0.25 W/m² in July throughout the model time series (2021-2100). Averaged across the year, the decrease in globally averaged radiative forcing is a lot less, from approximately 0.02 W/m² (2021–2060) to 0.08 W/m² (2061–2100) (Zampieri and Goessling 2019). In this study, all sea ice north of 66.5°N during winter was thickened.
    • Desch et al. (2017) estimated global yearly averaged decline in radiative forcing of 0.14 W/m². In this study sea ice covering the entire Arctic Ocean was thickened.
• Arctic region
  • Decreased absorption of 0.008-6.5 W/m²
    • After 1 year of deployment, van Dijke (2022) estimated in a model that regional absorbed energy decreased 0.72-1.2%, corresponding to a change in radiative forcing of 0.008-0.013 W/m². These estimates are for application to the Beaufort Sea or Transpolar Drift.
    • Modeling study by Zampieri and Goessling (2019) increased reflected solar radiation in the Arctic during summer of approximately 0 W/m² from 2021-2060 and approximately 6.5 W/m² for 2061–2100. In this study, all sea ice north of 66.5°N during winter was thickened.
    • Pumping water on top of ice also has a temporary effect on outgoing longwave radiation (F. Ypma pers. comm.).

• Direct or indirect impact on sea ice?
  • Direct impact on sea ice via thickening and melt reduction
• New or old ice?
  • Existing ice
    • van Dijke (2022) proposes to thicken first year ice as opposed to multi-year ice. Most newer marginal ice would otherwise be lost from the system, and the albedo modification benefits are the largest for first year ice.
• Impact on sea ice
  • Maintenance of summer sea ice for about 60 yrs, increases in thickness 0.7-1 m.
    • Modeling study demonstrated potential to maintain summer sea ice cover for next 60 yrs (Zampieri and Goessling 2019). In this study, all sea ice north of 66.5°N during winter was thickened.
    • Conceptual model reported potential increases of sea ice thickness up to 1 m (Desch et al. 2017). A follow up modeling study estimated increased sea ice thickness of 70 cm with 20 cm of flooding (Pauling and Bitz 2021).
    • If target Beaufort Gyre, ice likely to remain in area for 5-6 years. Ice can remain within the Transpolar Drift 1-2 years (van Dijke 2022).
    • Importantly, the impact on sea ice will depend on what the goal of deployment is, and the scale of deployment. Decreasing the amount of solar radiation in the Arctic will require a large surface area and yearly application to stabilize summer sea ice extent. Increasing the amount of multi-year ice requires additional thickness.

Scalability

• Unknown, depends on goal
  • The plan laid out in Desch et al. (2017) is for 10% of the Arctic Ocean area (100,000,000 km²).
  • Zampieri and Goessling 2019 recommend 10,000,000 pumping devices covering approximately 0.1km² each (10,000 km² total). If warming continues more devices would be required.
  • Arctic Reflections is targeting specific locations within the Arctic Ocean to maximize ice distribution. The goal is to prevent 100,000 km² of melting yearly via 100-1000 sites and stabilize summer sea ice extent.
    • Targeting the Beaufort Gyre may increase ice retention, while the Fram Strait, south of the Transpolar Drift, should be avoided due to the potential for ice export in this region (van Dijke 2022).
  • Real Ice is aiming for 1,000,000 km² of sea ice yearly to preserve current September sea ice extent and possibly restore September sea ice extent to levels from 1980s. They are targeting areas most a risk of summer melt or that could be restored to full-year coverage based on historical patterns and start of winter thickness.
  • Water volumes of 707-1,095 km³ (Beaufort Sea) and 386-464 km³ (Transpolar Drift) are required to avoid annual sea ice loss each year (322 km³ ice volume; 49,200 km² ice area; 83,400 km² ice extent; van Dijke 2022).

• Unknown
  • Some details on efficiency and efficacy of pumping and of flooding snow available in Desch et al. (2017), Pauling and Bitz (2021), and van Dijke (2022)
  • There are many tradeoffs that need to be considered related to timing, natural ice growth cycles, and impact on albedo (F. Ypma pers. comm.).

• Unknown
  • Real Ice and Arctic Reflections have plans to reach full scale in early 2030s.

• Unknown
  • To date studies of this technique have found minimal potential for global impact (Zampieri and Goessling 2019; Pauling and Bitz 2021).

• To be effective this technology would need to happen as soon as possible. As Arctic sea ice area further decreases there be less potential sea ice to apply this technique (Pauling and Bitz 2021). This concern depends on when the approach would be applied, with more ice being available during winter.
• This technique may become technically feasible within 20 years, but deployment and Arctic impact would require achieving scalability, which may not be able to happen within 20 years.

Cost

• $ billions
  • Initial estimate of $500 billion to build 10 million wind-powered pumps to deploy this technology (Desch et al. 2017).
  • Real Ice estimates cost to $43 billion over first 10 years (approximately $6 billion per year once at full scale, re-icing 1,000,000 km²). This cost includes energy production and distribution, production and maintenance of engineering components, and personnel.
  • Arctic Reflections’ cost estimates for focusing on 100,000 km² of ice are $1-10 billion.

• Unknown; potential to use renewable energy
  • Desch et al. (2017) proposed to power the system using wind.
  • Real Ice has proposed powering underwater drones with hydrogen fuel cells. Wind or solar power would be used to create green hydrogen for use with the hydrogen fuel cells. They estimate it will take 8MWh of energy to re-ice 1 km² of sea ice, including the start of winter and end of winter operations.
  • van Dijke (2022) suggests water volumes of 707-1,095 km³ (Beaufort Sea) and 386-464 km³ (Transpolar Drift) are required to avoid annual sea ice loss each year (322 km³ ice volume). The power required to pump this volume of water is 4.5-7.0 GW (Beaufort Sea) and 2.5-3.0 GW (Transpolar Drift).

Impact on

• Variable; increases of 0.39-0.66 for thickening ice and adding snow, increases of 0.33 for prevention of sea ice melt and conversion to open water, potential decrease in albedo of 0.05-0.15 from flooding snow.
  • New ice has an albedo of 0.15 – 0.42 (depending on presence of snow; Webster and Warren 2022). By thickening ice and adding snow, albedo may be increased to 0.81 (Webster and Warren 2022; values reported here are for broadband clear skies, but that paper also provides values for visible and near-infrared albedo)
  • Thickening sea ice allows snow and sea ice to persist longer in summer where open water would otherwise occur, giving rise to an albedo of closer to 0.4 for multiyear ice compared to 0.7 for open water near the sea ice edge (Perovich and Polashenski 2012).
  • Flooding snow far to the north of the ice edge, however, can decrease albedo in the by 0.05-0.15 (Pauling and Bitz 2021).
  • Thickened ice in field and laboratory studies is whiter than natural ice, but it is unknown if that characteristic is maintained over time (van Dijke in review). The whitening of the ice is likely due to difference in salinity between the original ice and the flooded ice or to having more air trapped in the flooded ice layer (van Dijke in review).
  • Impacts will be dependent on time of year. Avoiding open water and postponing ice melt will be most effective in June and July (e.g., postponing open water by 10-30 days in July; F. Ypma pers. comm.).
  • Impacts will also be dependent on melt rate, which varies by region. For example, a modeling study shows that adding 30 cm of thickness corresponds to 1 month of additional ice in the Transpolar Drift area and 2 weeks in the Beaufort Sea (van Dijke in review).

• Global
  • Minimal (0.02°C) to no global cooling effect (Zampieri and Goessling 2019; Pauling and Bitz 2021).
    • In the modeling study by Zampieri and Goessling 2019 all sea ice north of 66.5°N during winter was thickened. In the modeling study by Pauling and Bitz 2021sea ice covering the entire Arctic Ocean was thickened.
• Arctic region
  • Decreases in temperature in the Arctic of 1.3-2°C, with greatest decreases during summer.
    • Modeling study reported 1.3-1.4°C of cooling in the Arctic (Zampieri and Goessling 2019) during summer, plus warming in winter where pumps are active leading to net cooling in winter of 0.3°C and increases over time to warming of 0.5°C (2061-2100). The warm winter anomalies are due to maintaining a liquid water layer. In this study, all sea ice north of 66.5°N during winter was thickened.
    • Modeling study found up to 2°C cooling in the Arctic (Pauling and Bitz 2021) and noted that the temperature decrease was sensitive to the starting conditions. With less sea ice at the beginning of deployment the temperature decrease is less (Pauling and Bitz 2021). In this study sea ice covering the entire Arctic Ocean was thickened. This study used more realistic physical conditions than Zampieri and Goessling (2019) and did not find winter warming.

• Global
  • Decreases of approximately 0.25 W/m² in July, and 0.02-0.14 W/m² when averaged over the year.
    • Modeling study reports decreases in globally averaged solar radiative forcing from Arctic ice management of approximately 0.25 W/m² in July throughout the model time series (2021-2100). Averaged across the year, the decrease in globally averaged radiative forcing is a lot less, from approximately 0.02 W/m² (2021–2060) to 0.08 W/m² (2061–2100) (Zampieri and Goessling 2019). In this study, all sea ice north of 66.5°N during winter was thickened.
    • Desch et al. (2017) estimated global yearly averaged decline in radiative forcing of 0.14 W/m². In this study sea ice covering the entire Arctic Ocean was thickened.
  • Arctic region
    • Decreased absorption of 0.008-6.5 W/m²
      • After 1 year of deployment, van Dijke (2022) estimated in a model that regional absorbed energy decreased 0.72-1.2%, corresponding to a change in radiative forcing of 0.008-0.013 W/m². These estimates are for application to the Beaufort Sea or Transpolar Drift.
      • Modeling study by Zampieri and Goessling (2019) increased reflected solar radiation in the Arctic during summer of approximately 0 W/m² from 2021-2060 and approximately 6.5 W/m² for 2061–2100. In this study, all sea ice north of 66.5°N during winter was thickened.
      • Pumping water on top of ice also has a temporary effect on outgoing longwave radiation (F. Ypma pers. comm.).

• Direct or indirect impact on sea ice?
  • Direct impact on sea ice via thickening and melt reduction
• New or old ice?
  • Existing ice
    • van Dijke (2022) proposes to thicken first year ice as opposed to multi-year ice. Most newer marginal ice would otherwise be lost from the system, and the albedo modification benefits are the largest for first year ice.
• Impact on sea ice
  • Maintenance of summer sea ice for about 60 yrs, increases in thickness 0.7-1 m.
    • Modeling study demonstrated potential to maintain summer sea ice cover for next 60 yrs (Zampieri and Goessling 2019). In this study, all sea ice north of 66.5°N during winter was thickened.
    • Conceptual model reported potential increases of sea ice thickness up to 1 m (Desch et al. 2017). A follow up modeling study estimated increased sea ice thickness of 70 cm with 20 cm of flooding (Pauling and Bitz 2021).
    • If target Beaufort Gyre, ice likely to remain in area for 5-6 years. Ice can remain within the Transpolar Drift 1-2 years (van Dijke 2022).
    • Importantly, the impact on sea ice will depend on what the goal of deployment is, and the scale of deployment. Decreasing the amount of solar radiation in the Arctic will require a large surface area and yearly application to stabilize summer sea ice extent. Increasing the amount of multi-year ice requires additional thickness.

Scalability

• Unknown, depends on goal
  • The plan laid out in Desch et al. (2017) is for 10% of the Arctic Ocean area (100,000,000 km²).
  • Zampieri and Goessling 2019 recommend 10,000,000 pumping devices covering approximately 0.1km² each (10,000 km² total). If warming continues more devices would be required.
  • Arctic Reflections is targeting specific locations within the Arctic Ocean to maximize ice distribution. The goal is to prevent 100,000 km² of melting yearly via 100-1000 sites and stabilize summer sea ice extent.
    • Targeting the Beaufort Gyre may increase ice retention, while the Fram Strait, south of the Transpolar Drift, should be avoided due to the potential for ice export in this region (van Dijke 2022).
  • Real Ice is aiming for 1,000,000 km² of sea ice yearly to preserve current September sea ice extent and possibly restore September sea ice extent to levels from 1980s. They are targeting areas most a risk of summer melt or that could be restored to full-year coverage based on historical patterns and start of winter thickness.
  • Water volumes of 707-1,095 km³ (Beaufort Sea) and 386-464 km³ (Transpolar Drift) are required to avoid annual sea ice loss each year (322 km³ ice volume; 49,200 km² ice area; 83,400 km² ice extent; van Dijke 2022).

• Unknown
  • Some details on efficiency and efficacy of pumping and of flooding snow available in Desch et al. (2017), Pauling and Bitz (2021), and van Dijke (2022)
  • There are many tradeoffs that need to be considered related to timing, natural ice growth cycles, and impact on albedo (F. Ypma pers. comm.).

• Unknown
  • Real Ice and Arctic Reflections have plans to reach full scale in early 2030s.

• Unknown
  • To date studies of this technique have found minimal potential for global impact (Zampieri and Goessling 2019; Pauling and Bitz 2021).

• To be effective this technology would need to happen as soon as possible. As Arctic sea ice area further decreases there be less potential sea ice to apply this technique (Pauling and Bitz 2021). This concern depends on when the approach would be applied, with more ice being available during winter.
• This technique may become technically feasible within 20 years, but deployment and Arctic impact would require achieving scalability, which may not be able to happen within 20 years.

Cost

• $ billions
  • Initial estimate of $500 billion to build 10 million wind-powered pumps to deploy this technology (Desch et al. 2017).
  • Real Ice estimates cost to $43 billion over first 10 years (approximately $6 billion per year once at full scale, re-icing 1,000,000 km²). This cost includes energy production and distribution, production and maintenance of engineering components, and personnel.
  • Arctic Reflections’ cost estimates for focusing on 100,000 km² of ice are $1-10 billion.

• Unknown; potential to use renewable energy
  • Desch et al. (2017) proposed to power the system using wind.
  • Real Ice has proposed powering underwater drones with hydrogen fuel cells. Wind or solar power would be used to create green hydrogen for use with the hydrogen fuel cells. They estimate it will take 8MWh of energy to re-ice 1 km² of sea ice, including the start of winter and end of winter operations.
  • van Dijke (2022) suggests water volumes of 707-1,095 km³ (Beaufort Sea) and 386-464 km³ (Transpolar Drift) are required to avoid annual sea ice loss each year (322 km³ ice volume). The power required to pump this volume of water is 4.5-7.0 GW (Beaufort Sea) and 2.5-3.0 GW (Transpolar Drift).

Impact on

• Variable; increases of 0.39-0.66 for thickening ice and adding snow, increases of 0.33 for prevention of sea ice melt and conversion to open water, potential decrease in albedo of 0.05-0.15 from flooding snow.
  • New ice has an albedo of 0.15 – 0.42 (depending on presence of snow; Webster and Warren 2022). By thickening ice and adding snow, albedo may be increased to 0.81 (Webster and Warren 2022; values reported here are for broadband clear skies, but that paper also provides values for visible and near-infrared albedo)
  • Thickening sea ice allows snow and sea ice to persist longer in summer where open water would otherwise occur, giving rise to an albedo of closer to 0.4 for multiyear ice compared to 0.7 for open water near the sea ice edge (Perovich and Polashenski 2012).
  • Flooding snow far to the north of the ice edge, however, can decrease albedo in the by 0.05-0.15 (Pauling and Bitz 2021).
  • Thickened ice in field and laboratory studies is whiter than natural ice, but it is unknown if that characteristic is maintained over time (van Dijke in review). The whitening of the ice is likely due to difference in salinity between the original ice and the flooded ice or to having more air trapped in the flooded ice layer (van Dijke in review).
  • Impacts will be dependent on time of year. Avoiding open water and postponing ice melt will be most effective in June and July (e.g., postponing open water by 10-30 days in July; F. Ypma pers. comm.).
  • Impacts will also be dependent on melt rate, which varies by region. For example, a modeling study shows that adding 30 cm of thickness corresponds to 1 month of additional ice in the Transpolar Drift area and 2 weeks in the Beaufort Sea (van Dijke in review).

• Global
  • Minimal (0.02°C) to no global cooling effect (Zampieri and Goessling 2019; Pauling and Bitz 2021).
    • In the modeling study by Zampieri and Goessling 2019 all sea ice north of 66.5°N during winter was thickened. In the modeling study by Pauling and Bitz 2021sea ice covering the entire Arctic Ocean was thickened.
• Arctic region
  • Decreases in temperature in the Arctic of 1.3-2°C, with greatest decreases during summer.
    • Modeling study reported 1.3-1.4°C of cooling in the Arctic (Zampieri and Goessling 2019) during summer, plus warming in winter where pumps are active leading to net cooling in winter of 0.3°C and increases over time to warming of 0.5°C (2061-2100). The warm winter anomalies are due to maintaining a liquid water layer. In this study, all sea ice north of 66.5°N during winter was thickened.
    • Modeling study found up to 2°C cooling in the Arctic (Pauling and Bitz 2021) and noted that the temperature decrease was sensitive to the starting conditions. With less sea ice at the beginning of deployment the temperature decrease is less (Pauling and Bitz 2021). In this study sea ice covering the entire Arctic Ocean was thickened. This study used more realistic physical conditions than Zampieri and Goessling (2019) and did not find winter warming.

• Global
  • Decreases of approximately 0.25 W/m² in July, and 0.02-0.14 W/m² when averaged over the year.
    • Modeling study reports decreases in globally averaged solar radiative forcing from Arctic ice management of approximately 0.25 W/m² in July throughout the model time series (2021-2100). Averaged across the year, the decrease in globally averaged radiative forcing is a lot less, from approximately 0.02 W/m² (2021–2060) to 0.08 W/m² (2061–2100) (Zampieri and Goessling 2019). In this study, all sea ice north of 66.5°N during winter was thickened.
    • Desch et al. (2017) estimated global yearly averaged decline in radiative forcing of 0.14 W/m². In this study sea ice covering the entire Arctic Ocean was thickened.
  • Arctic region
    • Decreased absorption of 0.008-6.5 W/m²
      • After 1 year of deployment, van Dijke (2022) estimated in a model that regional absorbed energy decreased 0.72-1.2%, corresponding to a change in radiative forcing of 0.008-0.013 W/m². These estimates are for application to the Beaufort Sea or Transpolar Drift.
      • Modeling study by Zampieri and Goessling (2019) increased reflected solar radiation in the Arctic during summer of ∼0 W/m² from 2021-2060 and ∼6.5 W/m² for 2061–2100. In this study, all sea ice north of 66.5°N during winter was thickened.
      • Pumping water on top of ice also has a temporary effect on outgoing longwave radiation (F. Ypma pers. comm.).

• Direct or indirect impact on sea ice?
  • Direct impact on sea ice via thickening and melt reduction
• New or old ice?
  • Existing ice
    • van Dijke (2022) proposes to thicken first year ice as opposed to multi-year ice. Most newer marginal ice would otherwise be lost from the system, and the albedo modification benefits are the largest for first year ice.
• Impact on sea ice
  • Maintenance of summer sea ice for about 60 yrs, increases in thickness 0.7-1 m.
    • Modeling study demonstrated potential to maintain summer sea ice cover for next 60 yrs (Zampieri and Goessling 2019). In this study, all sea ice north of 66.5°N during winter was thickened.
    • Conceptual model reported potential increases of sea ice thickness up to 1 m (Desch et al. 2017). A follow up modeling study estimated increased sea ice thickness of 70 cm with 20 cm of flooding (Pauling and Bitz 2021).
    • If target Beaufort Gyre, ice likely to remain in area for 5-6 years. Ice can remain within the Transpolar Drift 1-2 years (van Dijke 2022).
    • Importantly, the impact on sea ice will depend on what the goal of deployment is, and the scale of deployment. Decreasing the amount of solar radiation in the Arctic will require a large surface area and yearly application to stabilize summer sea ice extent. Increasing the amount of multi-year ice requires additional thickness.

Scalability

• Unknown, depends on goal
  • The plan laid out in Desch et al. (2017) is for 10% of the Arctic Ocean area (100,000,000 km²).
  • Zampieri and Goessling 2019 recommend 10,000,000 pumping devices covering approximately 0.1km² each (10,000 km² total). If warming continues more devices would be required.
  • Arctic Reflections is targeting specific locations within the Arctic Ocean to maximize ice distribution. The goal is to prevent 100,000 km² of melting yearly via 100-1000 sites and stabilize summer sea ice extent.
    • Targeting the Beaufort Gyre may increase ice retention, while the Fram Strait, south of the Transpolar Drift, should be avoided due to the potential for ice export in this region (van Dijke 2022).
  • Real Ice is aiming for 1,000,000 km² of sea ice yearly to preserve current September sea ice extent and possibly restore September sea ice extent to levels from 1980s. They are targeting areas most a risk of summer melt or that could be restored to full-year coverage based on historical patterns and start of winter thickness.
  • Water volumes of 707-1,095 km³ (Beaufort Sea) and 386-464 km³ (Transpolar Drift) are required to avoid annual sea ice loss each year (322 km³ ice volume; 49,200 km² ice area; 83,400 km² ice extent; van Dijke 2022).

• Unknown
  • Some details on efficiency and efficacy of pumping and of flooding snow available in Desch et al. (2017), Pauling and Bitz (2021), and van Dijke (2022)
  • There are many tradeoffs that need to be considered related to timing, natural ice growth cycles, and impact on albedo (F. Ypma pers. comm.).

• Unknown
  • Real Ice and Arctic Reflections have plans to reach full scale in early 2030s.

• Unknown
  • To date studies of this technique have found minimal potential for global impact (Zampieri and Goessling 2019; Pauling and Bitz 2021).

• To be effective this technology would need to happen as soon as possible. As Arctic sea ice area further decreases there be less potential sea ice to apply this technique (Pauling and Bitz 2021). This concern depends on when the approach would be applied, with more ice being available during winter.
• This technique may become technically feasible within 20 years, but deployment and Arctic impact would require achieving scalability, which may not be able to happen within 20 years.

Cost

• $ billions
  • Initial estimate of $500 billion to build 10 million wind-powered pumps to deploy this technology (Desch et al. 2017).
  • Real Ice estimates cost to $43 billion over first 10 years (approximately $6 billion per year once at full scale, re-icing 1,000,000 km²). This cost includes energy production and distribution, production and maintenance of engineering components, and personnel.
  • Arctic Reflections’ cost estimates for focusing on 100,000 km² of ice are $1-10 billion.

• Unknown; potential to use renewable energy
  • Desch et al. (2017) proposed to power the system using wind.
  • Real Ice has proposed powering underwater drones with hydrogen fuel cells. Wind or solar power would be used to create green hydrogen for use with the hydrogen fuel cells. They estimate it will take 8MWh of energy to re-ice 1 km² of sea ice, including the start of winter and end of winter operations.
  • van Dijke (2022) suggests water volumes of 707-1,095 km³ (Beaufort Sea) and 386-464 km³ (Transpolar Drift) are required to avoid annual sea ice loss each year (322 km³ ice volume). The power required to pump this volume of water is 4.5-7.0 GW (Beaufort Sea) and 2.5-3.0 GW (Transpolar Drift).

• 4 – Conceptual and modeling studies with some testing of the system in a relevant environment and laboratory studies.
• Summary of existing literature and studies
  • Descriptions of methods and technologies for thickening ice in other industries (Masterson 2009), although these applications generally involve thicker ice than sea ice.
  • Concept paper (Desch et al. 2017) with follow up modeling papers (Pauling and Bitz 2021, Zampieri and Goessling 2019).
  • Modeling and laboratory studies conducted by van Dijke (2022).
  • Additional laboratory studies underway by Centre for Climate Repair (S. Fitzgerald pers. comm.) and Arctic Reflections (mentioned on website).
  • Field test of equipment in Nome, Alaska by Real Ice in 2023.
  • Field study by Real Ice with Arctic Reflections, Centre for Climate Repair, and Ekaluktutiak Hunters & Trappers Organisation at Canadian High Arctic Research Station (CHARS; 15-25 January 2024).
    • Testing of pumping equipment with hydrogen fuel cell.
    • Establishing a protocol for measurement of the effect of seawater pumping sea ice and control areas for both thickening during the winter and thinning during the summer.
    • Collaborating with SmartICE who will continue taking measurements.
  • Field study by Arctic Reflections with The University Centre in Svalbard and Delft University in Svalbard for proof of climate impact in April 2024. This study monitored ice thickness, temperature profile, as well as incoming and outgoing shortwave and longwave radiation.
  • Arctic Reflections is conducting an environmental impact assessment supported by the Climate Intervention Environmental Impact Fund.
  • Additional field measurements and larger area study planned by Real Ice in winter 2025.

• Possible
  • Real Ice is working on using existing technology to reduce the timeline to feasibility using water pumps already available for recreational and commercial purposes. The challenge is to pair these technologies with renewable energy sources. Real Ice is currently testing pumping technology paired with green hydrogen energy. They estimate that devices to scale green hydrogen energy production will be available in 2-5 years. Their goal is to generate enough sea ice to cover a 100 km² bay in the Arctic by 2027.
  • Arctic Reflections, after having conducted a thorough proof of impact field test in 2024, aim for a larger scale demonstration project using existing technology in the winter of 2025, and a first deployment of 100 km² in the winter of 2026.

• 4 – conceptual and modeling studies with some testing of the system in a relevant environment and laboratory studies.
• Summary of existing literature and studies
  • Descriptions of methods and technologies for thickening ice in other industries (Masterson 2009), although these applications generally involve thicker ice than sea ice.
  • Concept paper (Desch et al. 2017) with follow up modeling papers (Pauling and Bitz 2021, Zampieri and Goessling 2019).
  • Modeling and laboratory studies conducted by van Dijke (2022).
  • Additional laboratory studies underway by Centre for Climate Repair (S. Fitzgerald pers. comm.) and Arctic Reflections (mentioned on website).
  • Field test of equipment in Nome, Alaska by Real Ice in 2023.
  • Field study by Real Ice with Arctic Reflections, Centre for Climate Repair, and Ekaluktutiak Hunters & Trappers Organisation at Canadian High Arctic Research Station (CHARS; 15-25 January 2024).
    • Testing of pumping equipment with hydrogen fuel cell.
    • Establishing a protocol for measurement of the effect of seawater pumping sea ice and control areas for both thickening during the winter and thinning during the summer.
    • Collaborating with SmartICE who will continue taking measurements.
  • Field study by Arctic Reflections with The University Centre in Svalbard and Delft University in Svalbard for proof of climate impact in April 2024. This study monitored ice thickness, temperature profile, as well as incoming and outgoing shortwave and longwave radiation.
  • Arctic Reflections is conducting an environmental impact assessment supported by the Climate Intervention Environmental Impact Fund.
  • Additional field measurements and larger area study planned by Real Ice in winter 2025.

• Possible
  • Real Ice is working on using existing technology to reduce the timeline to feasibility using water pumps already available for recreational and commercial purposes. The challenge is to pair these technologies with renewable energy sources. Real Ice is currently testing pumping technology paired with green hydrogen energy. They estimate that devices to scale green hydrogen energy production will be available in 2-5 years. Their goal is to generate enough sea ice to cover a 100 km² bay in the Arctic by 2027.
  • Arctic Reflections, after having conducted a thorough proof of impact field test in 2024, aim for a larger scale demonstration project using existing technology in the winter of 2025, and a first deployment of 100 km² in the winter of 2026.

• 4 – conceptual and modeling studies with some testing of the system in a relevant environment and laboratory studies
• Summary of existing literature and studies
  • Descriptions of methods and technologies for thickening ice in other industries (Masterson 2009), although these applications generally involve thicker ice than sea ice.
  • Concept paper (Desch et al. 2017) with follow up modeling papers (Pauling and Bitz 2021, Zampieri and Goessling 2019).
  • Modeling and laboratory studies conducted by van Dijke (2022).
  • Additional laboratory studies underway by Centre for Climate Repair (S. Fitzgerald pers. comm.) and Arctic Reflections (mentioned on website).
  • Field test of equipment in Nome, Alaska by Real Ice in 2023.
  • Field study by Real Ice with Arctic Reflections, Centre for Climate Repair, and Ekaluktutiak Hunters & Trappers Organisation at Canadian High Arctic Research Station (CHARS; 15-25 January 2024).
    • Testing of pumping equipment with hydrogen fuel cell.
    • Establishing a protocol for measurement of effect of seawater pumping sea ice and control areas for both thickening during the winter and thinning during the summer.
    • Collaborating with SmartICE who will continue taking measurements.
  • Field study by Arctic Reflections with The University Centre in Svalbard and Delft University in Svalbard for proof of climate impact in April 2024. This study monitored ice thickness, temperature profile, as well as incoming and outgoing shortwave and longwave radiation.
  • Arctic Reflections is conducting an environmental impact assessment supported by the Climate Intervention Environmental Impact Fund.
  • Additional field measurements and larger area study planned by Real Ice in winter 2025.

• Possible
  • Real Ice is working on using existing technology to reduce the timeline to feasibility using water pumps already available for recreational and commercial purposes. The challenge is to pair these technologies with renewable energy sources. Real Ice is currently testing pumping technology paired with green hydrogen energy. They estimate that devices to scale green hydrogen energy production will be available in 2-5 years. Their goal is to generate enough sea ice to cover a 100 km² bay in the Arctic by 2027.
  • Arctic Reflections, after having conducted a thorough proof of impact field test in 2024, aim for a larger scale demonstration project using existing technology in the winter of 2025, and a first deployment of 100 km² in the winter of 2026.

• 4 – conceptual and modeling studies with some testing of the system in a relevant environment and laboratory studies
• Summary of existing literature and studies
  • Descriptions of methods and technologies for thickening ice in other industries (Masterson 2009), although these applications generally involve thicker ice than sea ice.
  • Concept paper (Desch et al. 2017) with follow up modeling papers (Pauling and Bitz 2021, Zampieri and Goessling 2019).
  • Modeling and laboratory studies conducted by van Dijke (2022).
  • Additional laboratory studies underway by Centre for Climate Repair (S. Fitzgerald pers. comm.) and Arctic Reflections (mentioned on website)
  • Field test of equipment in Nome, Alaska by Real Ice in 2023.
  • Field study by Real Ice with Arctic Reflections, Centre for Climate Repair, and Ekaluktutiak Hunters & Trappers Organisation at Canadian High Arctic Research Station (CHARS; 15-25 January 2024).
    • Testing of pumping equipment with hydrogen fuel cell.
    • Establishing a protocol for measurement of effect of seawater pumping sea ice and control areas for both thickening during the winter and thinning during the summer.
    • Collaborating with SmartICE who will continue taking measurements.
  • Field study by Arctic Reflections with The University Centre in Svalbard and Delft University in Svalbard for proof of climate impact in April 2024. This study monitored ice thickness, temperature profile, as well as incoming and outgoing shortwave and longwave radiation
  • Arctic Reflections is conducting an environmental impact assessment supported by the Climate Intervention Environmental Impact Fund.
  • Additional field measurements and larger area study planned by Real Ice in winter 2025.

• Possible
  • Real Ice is working on using existing technology to reduce the timeline to feasibility using water pumps already available for recreational and commercial purposes. The challenge is to pair these technologies with renewable energy sources. Real Ice is currently testing pumping technology paired with green hydrogen energy. They estimate that devices to scale green hydrogen energy production will be available in 2-5 years. Their goal is to generate enough sea ice to cover a 100 km² bay in the Arctic by 2027.
  • Arctic Reflections, after having conducted a thorough proof of impact field test in 2024, aim for a larger scale demonstration project using existing technology in the winter of 2025, and a first deployment of 100 km² in the winter of 2026.

• 4 – conceptual and modeling studies with some testing of the system in a relevant environment and laboratory studies
• Summary of existing literature and studies
  • Descriptions of methods and technologies for thickening ice in other industries (Masterson 2009), although these applications generally involve thicker ice than sea ice.
  • Concept paper (Desch et al. 2017) with follow up modeling papers (Pauling and Bitz 2021, Zampieri and Goessling 2019).
  • Modeling and laboratory studies conducted by van Dijke (2022).
  • Additional laboratory studies underway by Centre for Climate Repair (S. Fitzgerald pers. comm.) and Arctic Reflections (mentioned on website)
  • Field test of equipment in Nome, Alaska by Real Ice in 2023.
  • Field study by Real Ice with Arctic Reflections, Centre for Climate Repair, and Ekaluktutiak Hunters & Trappers Organisation at Canadian High Arctic Research Station (CHARS; 15-25 January 2024).
    • Testing of pumping equipment with hydrogen fuel cell.
    • Establishing a protocol for measurement of effect of seawater pumping sea ice and control areas for both thickening during the winter and thinning during the summer.
    • Collaborating with SmartICE who will continue taking measurements.
  • Field study by Arctic Reflections with The University Centre in Svalbard and Delft University in Svalbard for proof of climate impact in April 2024. This study monitored ice thickness, temperature profile, as well as incoming and outgoing shortwave and longwave radiation
  • Arctic Reflections is conducting an environmental impact assessment supported by the Climate Intervention Environmental Impact Fund.
  • Additional field measurements and larger area study planned by Real Ice in winter 2025.

• Possible
  • Real Ice is working on using existing technology to reduce the timeline to feasibility using water pumps already available for recreational and commercial purposes. The challenge is to pair these technologies with renewable energy sources. Real Ice is currently testing pumping technology paired with green hydrogen energy. They estimate that devices to scale green hydrogen energy production will be available in 2-5 years. Their goal is to generate enough sea ice to cover a 100 km² bay in the Arctic by 2027.
  • Arctic Reflections, after having conducted a thorough proof of impact field test in 2024, aim for a larger scale demonstration project using existing technology in the winter of 2025, and a first deployment of 100 km² in the winter of 2026.

• • 4 – conceptual and modeling studies with some testing of the system in a relevant environment and laboratory studies
  • Summary of existing literature and studies
    • Descriptions of methods and technologies for thickening ice in other industries (Masterson 2009), although these applications generally involve thicker ice than sea ice.
    • Concept paper (Desch et al. 2017) with follow up modeling papers (Pauling and Bitz 2021, Zampieri and Goessling 2019).
    • Modeling and laboratory studies conducted by van Dijke (2022).
    • Additional laboratory studies underway by Centre for Climate Repair (S. Fitzgerald pers. comm.) and Arctic Reflections (mentioned on website)
    • Field test of equipment in Nome, Alaska by Real Ice in 2023.
    • Field study by Real Ice with Arctic Reflections, Centre for Climate Repair, and Ekaluktutiak Hunters & Trappers Organisation at Canadian High Arctic Research Station (CHARS; 15-25 January 2024).
      • Testing of pumping equipment with hydrogen fuel cell.
      • Establishing a protocol for measurement of effect of seawater pumping sea ice and control areas for both thickening during the winter and thinning during the summer.
      • Collaborating with SmartICE who will continue taking measurements.
    • Field study by Arctic Reflections with The University Centre in Svalbard and Delft University in Svalbard for proof of climate impact in April 2024. This study monitored ice thickness, temperature profile, as well as incoming and outgoing shortwave and longwave radiation
    • Arctic Reflections is conducting an environmental impact assessment supported by the Climate Intervention Environmental Impact Fund.
    • Additional field measurements and larger area study planned by Real Ice in winter 2025.

• • Possible
    • Real Ice is working on using existing technology to reduce the timeline to feasibility using water pumps already available for recreational and commercial purposes. The challenge is to pair these technologies with renewable energy sources. Real Ice is currently testing pumping technology paired with green hydrogen energy. They estimate that devices to scale green hydrogen energy production will be available in 2-5 years. Their goal is to generate enough sea ice to cover a 100 km² bay in the Arctic by 2027.
    • Arctic Reflections, after having conducted a thorough proof of impact field test in 2024, aim for a larger scale demonstration project using existing technology in the winter of 2025, and a first deployment of 100 km² in the winter of 2026.

• TRL
  • 4 – conceptual and modeling studies with some testing of the system in a relevant environment and laboratory studies
  • Summary of existing literature and studies
    • Descriptions of methods and technologies for thickening ice in other industries (Masterson 2009), although these applications generally involve thicker ice than sea ice.
    • Concept paper (Desch et al. 2017) with follow up modeling papers (Pauling and Bitz 2021, Zampieri and Goessling 2019).
    • Modeling and laboratory studies conducted by van Dijke (2022).
    • Additional laboratory studies underway by Centre for Climate Repair (S. Fitzgerald pers. comm.) and Arctic Reflections (mentioned on website)
    • Field test of equipment in Nome, Alaska by Real Ice in 2023.
    • Field study by Real Ice with Arctic Reflections, Centre for Climate Repair, and Ekaluktutiak Hunters & Trappers Organisation at Canadian High Arctic Research Station (CHARS; 15-25 January 2024).
      • Testing of pumping equipment with hydrogen fuel cell.
      • Establishing a protocol for measurement of effect of seawater pumping sea ice and control areas for both thickening during the winter and thinning during the summer.
      • Collaborating with SmartICE who will continue taking measurements.
    • Field study by Arctic Reflections with The University Centre in Svalbard and Delft University in Svalbard for proof of climate impact in April 2024. This study monitored ice thickness, temperature profile, as well as incoming and outgoing shortwave and longwave radiation
    • Arctic Reflections is conducting an environmental impact assessment supported by the Climate Intervention Environmental Impact Fund.
    • Additional field measurements and larger area study planned by Real Ice in winter 2025.
• Technical feasibility within 10 yrs
  • Possible
    • Real Ice is working on using existing technology to reduce the timeline to feasibility using water pumps already available for recreational and commercial purposes. The challenge is to pair these technologies with renewable energy sources. Real Ice is currently testing pumping technology paired with green hydrogen energy. They estimate that devices to scale green hydrogen energy production will be available in 2-5 years. Their goal is to generate enough sea ice to cover a 100 km² bay in the Arctic by 2027.
    • Arctic Reflections, after having conducted a thorough proof of impact field test in 2024, aim for a larger scale demonstration project using existing technology in the winter of 2025, and a first deployment of 100 km² in the winter of 2026.

• TRL
  • 4 – conceptual and modeling studies with some testing of the system in a relevant environment and laboratory studies
  • Summary of existing literature and studies
    • Descriptions of methods and technologies for thickening ice in other industries (Masterson 2009), although these applications generally involve thicker ice than sea ice.
    • Concept paper (Desch et al. 2017) with follow up modeling papers (Pauling and Bitz 2021, Zampieri and Goessling 2019).
    • Modeling and laboratory studies conducted by van Dijke (2022).
    • Additional laboratory studies underway by Centre for Climate Repair (S. Fitzgerald pers. comm.) and Arctic Reflections (mentioned on website)
    • Field test of equipment in Nome, Alaska by Real Ice in 2023.
    • Field study by Real Ice with Arctic Reflections, Centre for Climate Repair, and Ekaluktutiak Hunters & Trappers Organisation at Canadian High Arctic Research Station (CHARS; 15-25 January 2024).
      • Testing of pumping equipment with hydrogen fuel cell.
      • Establishing a protocol for measurement of effect of seawater pumping sea ice and control areas for both thickening during the winter and thinning during the summer.
      • Collaborating with SmartICE who will continue taking measurements.
    • Field study by Arctic Reflections with The University Centre in Svalbard and Delft University in Svalbard for proof of climate impact in April 2024. This study monitored ice thickness, temperature profile, as well as incoming and outgoing shortwave and longwave radiation
    • Arctic Reflections is conducting an environmental impact assessment supported by the Climate Intervention Environmental Impact Fund.
    • Additional field measurements planned by Real Ice in May 2024 and larger area study in winter 2025.
• Technical feasibility within 10 yrs
  • Possible
    • Real Ice is working on using existing technology to reduce the timeline to feasibility using water pumps already available for recreational and commercial purposes. The challenge is to pair these technologies with renewable energy sources. Real Ice is currently testing pumping technology paired with green hydrogen energy. They estimate that devices to scale green hydrogen energy production will be available in 2-5 years. Their goal is to generate enough sea ice to cover a 100 km² bay in the Arctic by 2027.
    • Arctic Reflections, after having conducted a thorough proof of impact field test in 2024, aim for a larger scale demonstration project using existing technology in the winter of 2025, and a first deployment of 100 km² in the winter of 2026.

Physical and chemical changes

• Co-benefits
  • If the technique had a cooling effect in the Arctic, cooler temperatures may slow down melting of glaciers in Greenland, thereby reducing sea level rise.
  • If the technique had a cooling effect in the Arctic, cooler temperatures may slow down the thawing of permafrost, preventing release of methane.
  • Sea ice can reduce coastal erosion.
  • Thickening of sea ice has also been proposed as a potential method for enhancing downwelling ocean currents to aid in carbon sequestration in the deep ocean and preservation of the North Atlantic Deep Water (Zhou and Flynn 2005).
• Risks
  • Surface water can warm (Desch et al. 2017).
  • Atmospheric temperatures can increase in winter (Zampieri and Goessling 2019).
  • Changes in salinity profiles (van Dijke 2022) with increased brine release to ocean (Miller et al. 2020). (Note that Arctic Reflections, Delft University, and the UNIS have conducted ice coring and constructed salinity profiles for both thickened ice and reference ice during their field test with results expected in 2024.)
  • Snow during the melt season has an insulating effect. If snow is no longer present due to pumping/flooding could have increased melting (van Dijke 2022).
  • Changes to Arctic hydrological cycle with increased precipitation during winter in regions with pumping devices (Zampieri and Goessling 2019), drying across the Arctic Ocean in summer (but impact outside of the Arctic is weak).
  • Flooding snow-covered sea ice would alter the release of gases and aerosols (Miller et al. 2020) with unknown consequences. If aerosol flux increases, temperatures may warm (Miller et al. 2020). However, the variety of different chemicals involved makes predicting biogeochemical changes difficult.
  • Flooding of snow could alter CO₂ fluxes between the sea ice and the atmosphere with some times of year increasing release of CO₂ to the atmosphere (Miller et al. 2020).
  • Aerosols from ships or other infrastructure needed for this technology could impact the local climate (Miller et al. 2020).

Impacts on species

• Co-benefits
  • Sea ice is essential for some species and increasing its longevity may benefit them.
• Risks
  • Artificial light from operations may negatively impact species during winter.
  • Species associated with brine channels will be impacted with unknown consequences.
  • Underwater sound from operations may impact species.

Impacts on ecosystems

• Co-benefits
  • Increasing the longevity of sea ice may benefit sea ice ecosystems.
• Risks
  • Reduced photosynthesis via increased blockage of sunlight (Miller et al. 2020) to ice algae as well as phytoplankton found below the ice. Disruptions to phytoplankton blooms could impact Arctic ecosystems and carbon flux.
  • Flooding of sea ice could result in biological communities on top of the ice that would also release materials to the atmosphere such as dimethyl sulfide (Miller et al. 2020). Such biological communities could potentially darken the ice surface.
  • Artificial light from operations may negatively impact species during winter and have consequences on species interactions.
  • Species associated with brine channels will be impacted with unknown consequences to the ecosystem.
  • Underwater sound from operations may impact species with consequences for the ecosystem.

Impacts on society

• Co-benefits
  • Maintaining and preserving sea ice may protected Indigenous peoples’ way of life, including using sea ice for fishing, hunting, and mobility.
  • Sea ice reduces coastal erosion. Coastal erosion is a large threat to Indigenous communities (Brunner et al. 2004).
  • Employment of Indigenous people and local communities. Real Ice is employing local people in research efforts via Ekaluktutiak Hunters & Trappers Organisation.
  • Increasing ice area could impact existing and new shipping routes, this could also be seen as a risk.
• Risks
  • Increasing ice area could impact existing and new shipping routes, this could also be seen as a benefit.

Ease of reversibility

• Medium
  • If pumping ceased, ice would stop being thickened and return to natural state in < 10 years (Zampieri and Goessling 2019). There may be extensive infrastructure that would be need to be removed.

Risk of termination shock

• Medium
  • If pumping ceased, sea ice extent would likely go back to concentrations without intervention given whatever level of warming was currently present within 10 years (Zampieri and Goessling 2019).

Physical and chemical changes

• Co-benefits
  • If the technique had a cooling effect in the Arctic, cooler temperatures may slow down melting of glaciers in Greenland, thereby reducing sea level rise.
  • If the technique had a cooling effect in the Arctic, cooler temperatures may slow down the thawing of permafrost, preventing release of methane.
  • Sea ice can reduce coastal erosion.
  • Thickening of sea ice has also been proposed as a potential method for enhancing downwelling ocean currents to aid in carbon sequestration in the deep ocean and preservation of the North Atlantic Deep Water (Zhou and Flynn 2005).
• Risks
  • Surface water can warm (Desch et al. 2017).
  • Atmospheric temperatures can increase in winter (Zampieri and Goessling 2019).
  • Changes in salinity profiles (van Dijke 2022) with increased brine release to ocean (Miller et al. 2020). (Note that Arctic Reflections, Delft University, and the UNIS have conducted ice coring and constructed salinity profiles for both thickened ice and reference ice during their field test with results expected in 2024).
  • Snow during the melt season has an insulating effect. If snow is no longer present due to pumping/flooding could have increased melting (van Dijke 2022).
  • Changes to Arctic hydrological cycle with increased precipitation during winter in regions with pumping devices (Zampieri and Goessling 2019), drying across the Arctic Ocean in summer (but impact outside of the Arctic is weak).
  • Flooding snow-covered sea ice would alter the release of gases and aerosols (Miller et al. 2020) with unknown consequences. If aerosol flux increases, temperatures may warm (Miller et al. 2020). However, the variety of different chemicals involved makes predicting biogeochemical changes difficult.
  • Flooding of snow could alter CO₂ fluxes between the sea ice and the atmosphere with some times of year increasing release of CO₂ to the atmosphere (Miller et al. 2020).
  • Aerosols from ships or other infrastructure needed for this technology could impact the local climate (Miller et al. 2020).

Impacts on species

• Co-benefits
  • Sea ice is essential for some species and increasing its longevity may benefit them.
• Risks
  • Artificial light from operations may negatively impact species during winter.
  • Species associated with brine channels will be impacted with unknown consequences.
  • Underwater sound from operations may impact species.

Impacts on ecosystems

• Co-benefits
  • Increasing the longevity of sea ice may benefit sea ice ecosystems.
• Risks
  • Reduced photosynthesis via increased blockage of sunlight (Miller et al. 2020) to ice algae as well as phytoplankton found below the ice. Disruptions to phytoplankton blooms could impact Arctic ecosystems and carbon flux.
  • Flooding of sea ice could result in biological communities on top of the ice that would also release materials to the atmosphere such as dimethyl sulfide (Miller et al. 2020). Such biological communities could potentially darken the ice surface.
  • Artificial light from operations may negatively impact species during winter and have consequences on species interactions.
  • Species associated with brine channels will be impacted with unknown consequences to the ecosystem.
  • Underwater sound from operations may impact species with consequences for the ecosystem.

Impacts on society

• Co-benefits
  • Maintaining and preserving sea ice may protected Indigenous peoples’ way of life, including using sea ice for fishing, hunting, and mobility.
  • Sea ice reduces coastal erosion. Coastal erosion is a large threat to Indigenous communities (Brunner et al. 2004).
  • Employment of Indigenous people and local communities. Real Ice is employing local people in research efforts via Ekaluktutiak Hunters & Trappers Organisation.
  • Increasing ice area could impact existing and new shipping routes, this could also be seen as a risk.
• Risks
  • Increasing ice area could impact existing and new shipping routes, this could also be seen as a benefit.

Ease of reversibility

• Medium
  • If pumping ceased, ice would stop being thickened and return to natural state in < 10 years (Zampieri and Goessling 2019). There may be extensive infrastructure that would be need to be removed.

Risk of termination shock

• Medium
  • If pumping ceased, sea ice extent would likely go back to concentrations without intervention given whatever level of warming was currently present within 10 years (Zampieri and Goessling 2019).

Physical and chemical changes

• Co-benefits
  • If the technique had a cooling effect in the Arctic, cooler temperatures may slow down melting of glaciers in Greenland, thereby reducing sea level rise.
  • If the technique had a cooling effect in the Arctic, cooler temperatures may slow down the thawing of permafrost, preventing release of methane.
  • Sea ice can reduce coastal erosion.
  • Thickening of sea ice has also been proposed as a potential method for enhancing downwelling ocean currents to aid in carbon sequestration in the deep ocean and preservation of the North Atlantic Deep Water (Zhou and Flynn 2005).
• Risks
  • Surface water can warm (Desch et al. 2017).
  • Atmospheric temperatures can increase in winter (Zampieri and Goessling 2019).
  • Changes in salinity profiles (van Dijke 2022) with increased brine release to ocean (Miller et al. 2020). (Note that Arctic Reflections, Delft University, and the UNIS have conducted ice coring and constructed salinity profiles for both thickened ice and reference ice during their field test with results expected in 2024.)
  • Snow during the melt season has an insulating effect. If snow is no longer present due to pumping/flooding could have increased melting (van Dijke 2022).
  • Changes to Arctic hydrological cycle with increased precipitation during winter in regions with pumping devices (Zampieri and Goessling 2019), drying across Arctic Ocean in summer (but impact outside of the Arctic is weak).
  • Flooding snow-covered sea ice would alter the release of gases and aerosols (Miller et al. 2020) with unknown consequences. If aerosol flux increases, temperatures may warm (Miller et al. 2020). However, the variety of different chemicals involved make predicting biogeochemical changes difficult.
  • Flooding of snow could alter CO₂ fluxes between the sea ice and the atmosphere with some times of year increasing release of CO₂ to the atmosphere (Miller et al. 2020).
  • Aerosols from ships or other infrastructure needed for this technology could impact the local climate (Miller et al. 2020).

Impacts on species

• Co-benefits
  • Sea ice is essential for some species and increasing its longevity may benefit them.
• Risks
  • Artificial light from operations may negatively impact species during winter.
  • Species associated with brine channels will be impacted with unknown consequences.
  • Underwater sound from operations may impact species.

Impacts on ecosystems

• Co-benefits
  • Increasing the longevity of sea ice may benefit sea ice ecosystems.
• Risks
  • Reduced photosynthesis via increased blockage of sunlight (Miller et al. 2020) to ice algae as well as phytoplankton found below the ice. Disruptions to phytoplankton blooms could impact Arctic ecosystems and carbon flux.
  • Flooding of sea ice could result in biological communities on top of the ice that would also release materials to the atmosphere such as dimethyl sulfide (Miller et al. 2020). Such biological communities could potentially darken the ice surface.
  • Artificial light from operations may negatively impact species during winter and have consequences on species interactions.
  • Species associated with brine channels will be impacted with unknown consequences to the ecosystem.
  • Underwater sound from operations may impact species with consequences for the ecosystem.

Impacts on society

• Co-benefits
  • Maintaining and preserving sea ice may protected Indigenous peoples’ way of life, including using sea ice for fishing, hunting, and mobility.
  • Sea ice reduces coastal erosion. Coastal erosion is a large threat to Indigenous communities (Brunner et al. 2004).
  • Employment of Indigenous people and local communities. Real Ice is employing local people in research efforts via Ekaluktutiak Hunters & Trappers Organisation.
  • Increasing ice area could impact existing and new shipping routes, this could also be seen as a risk.
• Risks
  • Increasing ice area could impact existing and new shipping routes, this could also be seen as a benefit.

Ease of reversibility

• Medium
  • If pumping ceased, ice would stop being thickened and return to natural state in < 10 years (Zampieri and Goessling 2019). There may be extensive infrastructure that would be need to be removed.

Risk of termination shock

• Medium
  • If pumping ceased, sea ice extent would likely go back to concentrations without intervention given whatever level of warming was currently present within 10 years (Zampieri and Goessling 2019).

Physical and chemical changes

• Co-benefits
  • If the technique had a cooling effect in the Arctic, cooler temperatures may slow down melting of glaciers in Greenland, thereby reducing sea level rise.
  • If the technique had a cooling effect in the Arctic, cooler temperatures may slow down the thawing of permafrost, preventing release of methane.
  • Sea ice can reduce coastal erosion.
  • Thickening of sea ice has also been proposed as a potential method for enhancing downwelling ocean currents to aid in carbon sequestration in the deep ocean and preservation of the North Atlantic Deep Water (Zhou and Flynn 2005).
• Risks
  • Surface water can warm (Desch et al. 2017).
  • Atmospheric temperatures can increase in winter (Zampieri and Goessling 2019).
  • Changes in salinity profiles (van Dijke 2022) with increased brine release to ocean (Miller et al. 2020). (Note that Arctic Reflections, Delft University, and the UNIS have conducted ice coring and constructed salinity profiles for both thickened ice and reference ice during their field test with results expected in 2024.)
  • Snow during the melt season has an insulating effect. If snow is no longer present due to pumping/flooding could have increased melting (van Dijke 2022).
  • Changes to Arctic hydrological cycle with increased precipitation during winter in regions with pumping devices (Zampieri and Goessling 2019), drying across Arctic Ocean in summer (but impact outside of the Arctic is weak).
  • Flooding snow-covered sea ice would alter the release of gases and aerosols (Miller et al. 2020) with unknown consequences. If aerosol flux increases, temperatures may warm (Miller et al. 2020). However, the variety of different chemicals involved make predicting biogeochemical changes difficult.
  • Flooding of snow could alter CO₂ fluxes between the sea ice and the atmosphere with some times of year increasing release of CO₂ to the atmosphere (Miller et al. 2020).
  • Aerosols from ships or other infrastructure needed for this technology could impact the local climate (Miller et al. 2020).

Impacts on species

• Co-benefits
  • Sea ice is essential for some species and increasing its longevity may benefit them.
• Risks
  • Artificial light from operations may negatively impact species during winter.
  • Species associated with brine channels will be impacted with unknown consequences.
  • Underwater sound from operations may impact species.

Impacts on ecosystems

• Co-benefits
  • Increasing the longevity of sea ice may benefit sea ice ecosystems.
• Risks
  • Reduced photosynthesis via increased blockage of sunlight (Miller et al. 2020) to ice algae as well as phytoplankton found below the ice. Disruptions to phytoplankton blooms could impact Arctic ecosystems and carbon flux.
  • Flooding of sea ice could result in biological communities on top of the ice that would also release materials to the atmosphere such as dimethyl sulfide (Miller et al. 2020). Such biological communities could potentially darken the ice surface.
  • Artificial light from operations may negatively impact species during winter and have consequences on species interactions.
  • Species associated with brine channels will be impacted with unknown consequences to the ecosystem.
  • Underwater sound from operations may impact species with consequences for the ecosystem.

Impacts on society

• Co-benefits
  • Maintaining and preserving sea ice may protected Indigenous peoples’ way of life, including using sea ice for fishing, hunting, and mobility.
  • Sea ice reduces coastal erosion. Coastal erosion is a large threat to Indigenous communities (Brunner et al. 2004).
  • Employment of Indigenous people and local communities. Real Ice is employing local people in research efforts via Ekaluktutiak Hunters & Trappers Organisation.
  • Increasing ice area could impact existing and new shipping routes, this could also be seen as a risk.
• Risks
  • Increasing ice area could impact existing and new shipping routes, this could also be seen as a benefit.

Ease of reversibility

• If pumping ceased, ice would stop being thickened and return to natural state in < 10 years (Zampieri and Goessling 2019). There may be extensive infrastructure that would be need to be removed.

Risk of termination shock

• If pumping ceased, sea ice extent would likely go back to concentrations without intervention given whatever level of warming was currently present within 10 years (Zampieri and Goessling 2019).

• Co-benefits
  • If the technique had a cooling effect in the Arctic, cooler temperatures may slow down melting of glaciers in Greenland, thereby reducing sea level rise.
  • If the technique had a cooling effect in the Arctic, cooler temperatures may slow down the thawing of permafrost, preventing release of methane.
  • Sea ice can reduce coastal erosion.
  • Thickening of sea ice has also been proposed as a potential method for enhancing downwelling ocean currents to aid in carbon sequestration in the deep ocean and preservation of the North Atlantic Deep Water (Zhou and Flynn 2005).
• Risks
  • Surface water can warm (Desch et al. 2017).
  • Atmospheric temperatures can increase in winter (Zampieri and Goessling 2019).
  • Changes in salinity profiles (van Dijke 2022) with increased brine release to ocean (Miller et al. 2020). (Note that Arctic Reflections, Delft University, and the UNIS have conducted ice coring and constructed salinity profiles for both thickened ice and reference ice during their field test with results expected in 2024.)
  • Snow during the melt season has an insulating effect. If snow is no longer present due to pumping/flooding could have increased melting (van Dijke 2022).
  • Changes to Arctic hydrological cycle with increased precipitation during winter in regions with pumping devices (Zampieri and Goessling 2019), drying across Arctic Ocean in summer (but impact outside of the Arctic is weak).
  • Flooding snow-covered sea ice would alter the release of gases and aerosols (Miller et al. 2020) with unknown consequences. If aerosol flux increases, temperatures may warm (Miller et al. 2020). However, the variety of different chemicals involved make predicting biogeochemical changes difficult.
  • Flooding of snow could alter CO₂ fluxes between the sea ice and the atmosphere with some times of year increasing release of CO₂ to the atmosphere (Miller et al. 2020).
  • Aerosols from ships or other infrastructure needed for this technology could impact the local climate (Miller et al. 2020).

• Co-benefits
  • Sea ice is essential for some species and increasing its longevity may benefit them.
• Risks
  • Artificial light from operations may negatively impact species during winter.
  • Species associated with brine channels will be impacted with unknown consequences.
  • Underwater sound from operations may impact species.

• Co-benefits
  • Increasing the longevity of sea ice may benefit sea ice ecosystems.
• Risks
  • Reduced photosynthesis via increased blockage of sunlight (Miller et al. 2020) to ice algae as well as phytoplankton found below the ice. Disruptions to phytoplankton blooms could impact Arctic ecosystems and carbon flux.
  • Flooding of sea ice could result in biological communities on top of the ice that would also release materials to the atmosphere such as dimethyl sulfide (Miller et al. 2020). Such biological communities could potentially darken the ice surface.
  • Artificial light from operations may negatively impact species during winter and have consequences on species interactions.
  • Species associated with brine channels will be impacted with unknown consequences to the ecosystem.
  • Underwater sound from operations may impact species with consequences for the ecosystem.

• Co-benefits
  • Maintaining and preserving sea ice may protected Indigenous peoples’ way of life, including using sea ice for fishing, hunting, and mobility.
  • Sea ice reduces coastal erosion. Coastal erosion is a large threat to Indigenous communities (Brunner et al. 2004).
  • Employment of Indigenous people and local communities. Real Ice is employing local people in research efforts via Ekaluktutiak Hunters & Trappers Organisation.
  • Increasing ice area could impact existing and new shipping routes, this could also be seen as a risk.
• Risks
  • Increasing ice area could impact existing and new shipping routes, this could also be seen as a benefit.

• If pumping ceased, ice would stop being thickened and return to natural state in < 10 years (Zampieri and Goessling 2019). There may be extensive infrastructure that would be need to be removed.

• If pumping ceased, sea ice extent would likely go back to concentrations without intervention given whatever level of warming was currently present within 10 years (Zampieri and Goessling 2019).

• Co-benefits
  • If the technique had a cooling effect in the Arctic, cooler temperatures may slow down melting of glaciers in Greenland, thereby reducing sea level rise.
  • If the technique had a cooling effect in the Arctic, cooler temperatures may slow down the thawing of permafrost, preventing release of methane.
  • Sea ice can reduce coastal erosion.
  • Thickening of sea ice has also been proposed as a potential method for enhancing downwelling ocean currents to aid in carbon sequestration in the deep ocean and preservation of the North Atlantic Deep Water (Zhou and Flynn 2005).
• Risks
  • Surface water can warm (Desch et al. 2017)
  • Atmospheric temperatures can increase in winter (Zampieri and Goessling 2019)
  • Changes in salinity profiles (van Dijke 2022) with increased brine release to ocean (Miller et al. 2020). (Note that Arctic Reflections, Delft University, and the UNIS have conducted ice coring and constructed salinity profiles for both thickened ice and reference ice during their field test with results expected in 2024.)
  • Snow during the melt season has an insulating effect. If snow is no longer present due to pumping/flooding could have increased melting (van Dijke 2022)
  • Changes to Arctic hydrological cycle with increased precipitation during winter in regions with pumping devices (Zampieri and Goessling 2019), drying across Arctic Ocean in summer (but impact outside of the Arctic is weak)
  • Flooding snow-covered sea ice would alter the release of gases and aerosols (Miller et al. 2020) with unknown consequences. If aerosol flux increases, temperatures may warm (Miller et al. 2020). However, the variety of different chemicals involved make predicting biogeochemical changes difficult.
  • Flooding of snow could alter CO₂ fluxes between the sea ice and the atmosphere with some times of year increasing release of CO₂ to the atmosphere (Miller et al. 2020)
  • Aerosols from ships or other infrastructure needed for this technology could impact the local climate (Miller et al. 2020)

• Co-benefits
  • Sea ice is essential for some species and increasing its longevity may benefit them.
• Risks
  • Artificial light from operations may negatively impact species during winter.
  • Species associated with brine channels will be impacted with unknown consequences.
  • Underwater sound from operations may impact species.

• Co-benefits
  • Increasing the longevity of sea ice may benefit sea ice ecosystems.
• Risks
  • Reduced photosynthesis via increased blockage of sunlight (Miller et al. 2020) to ice algae as well as phytoplankton found below the ice. Disruptions to phytoplankton blooms could impact Arctic ecosystems and carbon flux.
  • Flooding of sea ice could result in biological communities on top of the ice that would also release materials to the atmosphere such as dimethyl sulfide (Miller et al. 2020). Such biological communities could potentially darken the ice surface.
  • Artificial light from operations may negatively impact species during winter and have consequences on species interactions.
  • Species associated with brine channels will be impacted with unknown consequences to the ecosystem.
  • Underwater sound from operations may impact species with consequences for the ecosystem.

• Co-benefits
  • Maintaining and preserving sea ice may protected Indigenous peoples’ way of life, including using sea ice for fishing, hunting, and mobility.
  • Sea ice reduces coastal erosion. Coastal erosion is a large threat to Indigenous communities (Brunner et al. 2004).
  • Employment of Indigenous people and local communities. Real Ice is employing local people in research efforts via Ekaluktutiak Hunters & Trappers Organisation.
  • Increasing ice area could impact existing and new shipping routes, this could also be seen as a risk.
• Risks
  • Increasing ice area could impact existing and new shipping routes, this could also be seen as a benefit.

• If pumping ceased, ice would stop being thickened and return to natural state in < 10 years (Zampieri and Goessling 2019). There may be extensive infrastructure that would be need to be removed.

• If pumping ceased, sea ice extent would likely go back to concentrations without intervention given whatever level of warming was currently present within 10 years (Zampieri and Goessling 2019)

• Applicable to all approaches within Ice Management:
  • For all Ice Management approaches, research and testing could be done within national jurisdiction (territorial seas or Exclusive Economic Zones (EEZs); note that different legal rules apply to territorial seas and EEZs). Scalability may require deployment to additional areas within international waters.  See “Existing governance” below for other available information on relevant governance structures.
• Specific to Ice Thickening:
  • No additional information.

• Applicable to all approaches within Ice Management:
  • The Arctic Ocean is governed by the United Nations Convention on the Law of the Sea (UNCLOS), which includes all Arctic coastal states except the United States. The United States, however, is bound to customary law “including customs codified or that have emerged from UNCLOS” (Argüello and Johansson 2022).
    • UNCLOS and marine scientific research (MSR):
      • MSR is governed by Part XIII of UNCLOS. In general, the right of states to conduct MSR is subject to the rights and duties of other states under UNCLOS (UNCLOS Article 238). There is a duty on parties to promote and facilitate MSR (UNCLOS Article 239).
      • MSR shall be conducted exclusively for peaceful purposes, it may not unjustifiably interfere with other legitimate uses of the sea, and it must be conducted in compliance with all relevant regulations adopted in conformity with the Convention, including those for the protection and preservation of the marine environment (UNCLOS Article 240).
      • States are responsible and liable for damage caused by pollution of the marine environment arising out of MSR undertaken by them or on their behalf (UNCLOS Article 263(3)).
        • Any approaches that involve adding material or energy to the ocean that would cause or be likely to cause damage to the marine environment would constitute “pollution of the marine environment” within the meaning of Article 1(1)(4) of UNCLOS, and States would have a duty to minimize the pollution pursuant to Article 194.
      • National Jurisdiction and MSR under UNCLOS
        • In a coastal state’s territorial sea (12 nautical miles from shore baseline), the coastal state has the exclusive right to regulate, authorize, and conduct MSR.
        • In a coastal state’s EEZ (200 nautical miles from shore baseline), coastal states also have the right to regulate, authorize, and conduct MSR, and MSR by other states requires the consent of the coastal state (UNCLOS Article 246(2)). States ordinarily give their consent, and they are required to adopt rules to ensure that consent is not delayed or denied unreasonably. UNCLOS further specifies grounds for refusing consent, including if the MSR involves introducing harmful substances into the marine environment (UNCLOS Article 246(5)(b)).
      • Areas outside National Jurisdiction and MSR under UNCLOS
        • On the high seas, UNCLOS provides for freedom of MSR (UNCLOS Article 87(1)(f)), but it must be done with due regard for the interests of other States in their exercise of the freedom of the high seas (Articles 87(2)).
        • The high seas are reserved for peaceful purposes (Article 88) and no state may subject a portion of high seas to its sovereignty (Article 89).
      • The 2017 Agreement on Enhancing Arctic Scientific Cooperation is relevant. This is a legally binding agreement signed in 2017 by all Arctic States negotiated in the Arctic Council. It promotes international cooperation and favorable conditions for conducting scientific research, facilitates access to research areas, infrastructure, and facilities, and promotes education and training of scientists in Arctic issues. The agreement also encourages participants to utilize traditional and local knowledge as appropriate as well as encourages communication between traditional and local knowledge holders and participants. This may provide a framework for consultation with stakeholders including Indigenous peoples in intervention research, planning, and testing (Chuffart et al. 2023).
      • The Arctic Council has been called upon as a venue for providing oversight on approaches to slow the loss of Arctic sea ice, or to establish working groups to provide guidance (Bodansky and Hunt 2020, Bennett et al. 2022). If the objective of the approach is to slow the loss of Arctic sea ice, rather than altering global temperatures, the Arctic parties have the primary interest (Bodansky and Hunt 2020). However, the current geopolitical landscape and lack of participation from Russia make consensus difficult.
      • See Argüello and Johansson (2022) for further details of governance related to ice management.
    • Specific to Ice Thickening:
      • Research to date has been on small scales and governed by regional bodies.
      • Desch et al. (2017) argued that since the goal of ice thickening may be to restore Arctic sea ice to a previous state, this technique is more like restoration than geoengineering. Bodansky and Hunt (2020) make a similar argument that localized interventions are more like mitigation and adaptation.

• Here we define justice related to approaches to slow the loss of Arctic sea ice through distributive justice, procedural justice, and restorative justice. Following COMEST (2023), we consider questions of ethics through a justice lens. Note that this is not an exhaustive list of justice dimensions and as the field advances, so will the related considerations and dimensions.
• Distributive justice
  • Applicable to all approaches within Ice Management:
    • If distributive justice is considered, the objective would be that benefits and costs of research or potential deployment of the approach be distributed fairly while protecting the basic rights of the most vulnerable.
  • Specific to Ice Thickening:
    • No additional information.
• Procedural justice
  • Applicable to all approaches within Ice Management:
    • If procedural justice is considered, people affected by research would have an opportunity to participate and have a say in how the approach will be researched, deployed, and governed.
    • Bennett et al. (2022) suggests an inclusive governance approach that incorporates stakeholder concerns in the design and deployment of approaches and effectively communicates risk. Within the development of such a framework there is an opportunity to prioritize Indigenous self-determination and procedural justice (Chuffart et al. 2023). Note, however, that stakeholders may also include non-local people.
  • Specific to Ice Thickening:
    • Some researchers working on this approach have engaged and worked with local people living in research areas.
• Restorative justice
  • Applicable to all approaches within Ice Management:
    • If restorative justice is considered, plans would be developed for those who could be harmed by the approach to be compensated, rehabilitated, or restored.
  • Specific to Ice Thickening:
    • As of the writing of this version, we are not aware of any plans for those who could be harmed by the approach to be compensated, rehabilitated, or restored. There is an argument that ice thickening serves to restore sea ice (Desch et al. 2017), which would potentially make this technique a method for restorative justice to communities suffering from sea ice loss. However, there is not enough knowledge about this approach to know about its potential negative consequences for species and ecosystems and therefore its restoration efficacy.

• Real Ice is working with Indigenous communities in Canada (Ekaluktutiak Hunters & Trappers Organisation).
• Arctic Reflections has given public talks, been featured in a documentary, and is endorsed as a UN Decade of Ocean Science Action.

• Applicable to all approaches within Ice Management:
  • The principle of free, prior, and informed consent (FPIC) in the United Nations Declaration on the Rights of Indigenous Peoples (UNDRIP) is the foundation for engagement with Indigenous Peoples.
  • Particular to any potential Arctic research or deployment, The Inuit Circumpolar Council (2022) has published Circumpolar Inuit Protocols for Equitable and Ethical Engagement, which include eight protocols:
    • ‘Nothing About Us Without Us’ – Always Engage with Inuit
    • Recognize Indigenous Knowledge in its Own Right
    • Practice Good Governance
    • Communication with Intent
    • Exercising Accountability – Building Trust
    • Building Meaningful Partnerships
    • Information, Data Sharing, Ownership, and Permissions
    • Equitably Fund Inuit Representation and Knowledge
  • Any meaningful engagement with Indigenous peoples needs to consider context. Whyte (2018) states, “Indigenous voices should be involved in scientific and policy discussions of different types of geoengineering. But, context matters. Geoengineering discourses cannot just be associated with geoengineering to the exclusion of topics and solutions that Indigenous peoples value.”
• Specific to Ice Thickening:
  • Real Ice is working with Indigenous communities in Canada (Ekaluktutiak Hunters & Trappers Organisation).

• Applicable to all approaches within Ice Management:
  • For all Ice Management approaches, research and testing could be done within national jurisdiction (territorial seas or Exclusive Economic Zones (EEZs); note that different legal rules apply to territorial seas and EEZs). Scalability may require deployment to additional areas within international waters.  See “Existing governance” below for other available information on relevant governance structures.
• Specific to Ice Thickening:
  • No additional information.

• Applicable to all approaches within Ice Management:
  • The Arctic Ocean is governed by the United Nations Convention on the Law of the Sea (UNCLOS), which includes all Arctic coastal states except the United States. The United States, however, is bound to customary law “including customs codified or that have emerged from UNCLOS” (Argüello and Johansson 2022).
    • UNCLOS and marine scientific research (MSR):
      • MSR is governed by Part XIII of UNCLOS. In general, the right of states to conduct MSR is subject to the rights and duties of other states under UNCLOS (UNCLOS Article 238). There is a duty on parties to promote and facilitate MSR (UNCLOS Article 239).
      • MSR shall be conducted exclusively for peaceful purposes, it may not unjustifiably interfere with other legitimate uses of the sea, and it must be conducted in compliance with all relevant regulations adopted in conformity with the Convention, including those for the protection and preservation of the marine environment (UNCLOS Article 240).
      • States are responsible and liable for damage caused by pollution of the marine environment arising out of MSR undertaken by them or on their behalf (UNCLOS Article 263(3)).
        • Any approaches that involve adding material or energy to the ocean that would cause or be likely to cause damage to the marine environment would constitute “pollution of the marine environment” within the meaning of Article 1(1)(4) of UNCLOS, and States would have a duty to minimize the pollution pursuant to Article 194.
      • National Jurisdiction and MSR under UNCLOS
        • In a coastal state’s territorial sea (12 nautical miles from shore baseline), the coastal state has the exclusive right to regulate, authorize, and conduct MSR.
        • In a coastal state’s EEZ (200 nautical miles from shore baseline), coastal states also have the right to regulate, authorize, and conduct MSR, and MSR by other states requires the consent of the coastal state (UNCLOS Article 246(2)). States ordinarily give their consent, and they are required to adopt rules to ensure that consent is not delayed or denied unreasonably. UNCLOS further specifies grounds for refusing consent, including if the MSR involves introducing harmful substances into the marine environment (UNCLOS Article 246(5)(b)).
      • Areas outside National Jurisdiction and MSR under UNCLOS
        • On the high seas, UNCLOS provides for freedom of MSR (UNCLOS Article 87(1)(f)), but it must be done with due regard for the interests of other States in their exercise of the freedom of the high seas (Articles 87(2)).
        • The high seas are reserved for peaceful purposes (Article 88) and no state may subject a portion of high seas to its sovereignty (Article 89).
      • The 2017 Agreement on Enhancing Arctic Scientific Cooperation is relevant. This is a legally binding agreement signed in 2017 by all Arctic States negotiated in the Arctic Council. It promotes international cooperation and favorable conditions for conducting scientific research, facilitates access to research areas, infrastructure, and facilities, and promotes education and training of scientists in Arctic issues. The agreement also encourages participants to utilize traditional and local knowledge as appropriate as well as encourages communication between traditional and local knowledge holders and participants. This may provide a framework for consultation with stakeholders including Indigenous peoples in intervention research, planning, and testing (Chuffart et al. 2023).
      • The Arctic Council has been called upon as a venue for providing oversight on approaches to slow the loss of Arctic sea ice, or to establish working groups to provide guidance (Bodansky and Hunt 2020, Bennett et al. 2022). If the objective of the approach is to slow the loss of Arctic sea ice, rather than altering global temperatures, the Arctic parties have the primary interest (Bodansky and Hunt 2020). However, the current geopolitical landscape and lack of participation from Russia make consensus difficult.
      • See Argüello and Johansson (2022) for further details of governance related to ice management.
    • Specific to Ice Thickening:
      • Research to date has been on small scales and governed by regional bodies.
      • Desch et al. (2017) argued that since the goal of ice thickening may be to restore Arctic sea ice to a previous state, this technique is more like restoration than geoengineering. Bodansky and Hunt (2020) make a similar argument that localized interventions are more like mitigation and adaptation.

• Here we define justice related to approaches to slow the loss of Arctic sea ice through distributive justice, procedural justice, and restorative justice. Following COMEST (2023), we consider questions of ethics through a justice lens. Note that this is not an exhaustive list of justice dimensions and as the field advances, so will the related considerations and dimensions.
• Distributive justice
  • Applicable to all approaches within Ice Management:
    • If distributive justice is considered, the objective would be that benefits and costs of research or potential deployment of the approach be distributed fairly while protecting the basic rights of the most vulnerable.
  • Specific to Ice Thickening:
    • No additional information.
• Procedural justice
  • Applicable to all approaches within Ice Management:
    • If procedural justice is considered, people affected by research would have an opportunity to participate and have a say in how the approach will be researched, deployed, and governed.
    • Bennett et al. (2022) suggests an inclusive governance approach that incorporates stakeholder concerns in the design and deployment of approaches and effectively communicates risk. Within the development of such a framework there is an opportunity to prioritize Indigenous self-determination and procedural justice (Chuffart et al. 2023). Note, however, that stakeholders may also include non-local people.
  • Specific to Ice Thickening:
    • Some researchers working on this approach have engaged and worked with local people living in research areas.
• Restorative justice
  • Applicable to all approaches within Ice Management:
    • If restorative justice is considered, plans would be developed for those who could be harmed by the approach to be compensated, rehabilitated, or restored.
  • Specific to Ice Thickening:
    • As of the writing of this version, we are not aware of any plans for those who could be harmed by the approach to be compensated, rehabilitated, or restored. There is an argument that ice thickening serves to restore sea ice (Desch et al. 2017), which would potentially make this technique a method for restorative justice to communities suffering from sea ice loss. However, there is not enough knowledge about this approach to know about its potential negative consequences for species and ecosystems and therefore its restoration efficacy.

• Real Ice is working with Indigenous communities in Canada (Ekaluktutiak Hunters & Trappers Organisation).
• Arctic Reflections has given public talks, been featured in a documentary, and is endorsed as a UN Decade of Ocean Science Action.

• Applicable to all approaches within Ice Management:
  • The principle of free, prior, and informed consent (FPIC) in the United Nations Declaration on the Rights of Indigenous Peoples (UNDRIP) is the foundation for engagement with Indigenous Peoples.
  • Particular to any potential Arctic research or deployment, The Inuit Circumpolar Council (2022) has published Circumpolar Inuit Protocols for Equitable and Ethical Engagement, which include eight protocols:
    • ‘Nothing About Us Without Us’ – Always Engage with Inuit
    • Recognize Indigenous Knowledge in its Own Right
    • Practice Good Governance
    • Communication with Intent
    • Exercising Accountability – Building Trust
    • Building Meaningful Partnerships
    • Information, Data Sharing, Ownership, and Permissions
    • Equitably Fund Inuit Representation and Knowledge
  • Any meaningful engagement with Indigenous peoples needs to consider context. Whyte (2018) states, “Indigenous voices should be involved in scientific and policy discussions of different types of geoengineering. But, context matters. Geoengineering discourses cannot just be associated with geoengineering to the exclusion of topics and solutions that Indigenous peoples value.”.
• Specific to Ice Thickening:
  • Real Ice is working with Indigenous communities in Canada (Ekaluktutiak Hunters & Trappers Organisation).

• Applicable to all approaches within Ice Management:
  • For all Ice Management approaches, research and testing could be done within national jurisdiction (territorial seas or Exclusive Economic Zones (EEZs); note that different legal rules apply to territorial seas and EEZs). Scalability may require deployment to additional areas within international waters.  See “Existing governance” for other available information on relevant governance structures.
• Specific to Ice Thickening:
  • No additional information.

• Applicable to all approaches within Ice Management:
  • The Arctic Ocean is governed by the United Nations Convention on the Law of the Sea (UNCLOS), which includes all Arctic coastal states except the United States. The United States, however, is bound to customary law “including customs codified or that have emerged from UNCLOS” (Argüello and Johansson 2022).
    • UNCLOS and marine scientific research (MSR):
      • MSR is governed by Part XIII of UNCLOS. In general, the right of states to conduct MSR is subject to the rights and duties of other states under UNCLOS (UNCLOS Article 238). There is a duty on parties to promote and facilitate MSR (UNCLOS Article 239).
      • MSR shall be conducted exclusively for peaceful purposes, it may not unjustifiably interfere with other legitimate uses of the sea, and it must be conducted in compliance with all relevant regulations adopted in conformity with the Convention, including those for the protection and preservation of the marine environment (UNCLOS Article 240).
      • States are responsible and liable for damage caused by pollution of the marine environment arising out of MSR undertaken by them or on their behalf (UNCLOS Article 263(3)).
        • Any approaches that involve adding material or energy to the ocean that would cause or be likely to cause damage to the marine environment would constitute “pollution of the marine environment” within the meaning of Article 1(1)(4) of UNCLOS, and States would have a duty to minimize the pollution pursuant to Article 194.
      • National Jurisdiction and MSR under UNCLOS
        • In a coastal state’s territorial sea (12 nautical miles from shore baseline), the coastal state has the exclusive right to regulate, authorize, and conduct MSR.
        • In a coastal state’s EEZ (200 nautical miles from shore baseline), coastal states also have the right to regulate, authorize, and conduct MSR, and MSR by other states requires the consent of the coastal state (UNCLOS Article 246(2)). States ordinarily give their consent, and they are required to adopt rules to ensure that consent is not delayed or denied unreasonably. UNCLOS further specifies grounds for refusing consent, including if the MSR involves introducing harmful substances into the marine environment (UNCLOS Article 246(5)(b)).
      • Areas outside National Jurisdiction and MSR under UNCLOS
        • On the high seas, UNCLOS provides for freedom of MSR (UNCLOS Article 87(1)(f)), but it must be done with due regard for the interests of other States in their exercise of the freedom of the high seas (Articles 87(2)).
        • The high seas are reserved for peaceful purposes (Article 88) and no state may subject a portion of high seas to its sovereignty (Article 89).
      • The 2017 Agreement on Enhancing Arctic Scientific Cooperation is relevant. This is a legally binding agreement signed in 2017 by all Arctic States negotiated in the Arctic Council. It promotes international cooperation and favorable conditions for conducting scientific research, facilitates access to research areas, infrastructure, and facilities, and promotes education and training of scientists in Arctic issues. The agreement also encourages participants to utilize traditional and local knowledge as appropriate as well as encourages communication between traditional and local knowledge holders and participants. This may provide a framework for consultation with stakeholders including Indigenous peoples in intervention research, planning, and testing (Chuffart et al. 2023).
      • The Arctic Council has been called upon as a venue for providing oversight on approaches to slow the loss of Arctic sea ice, or to establish working groups to provide guidance (Bodansky and Hunt 2020, Bennett et al. 2022). If the objective of the approach is to slow the loss of Arctic sea ice, rather than altering global temperatures, the Arctic parties have the primary interest (Bodansky and Hunt 2020). However, the current geopolitical landscape and lack of participation from Russia makes consensus difficult.
      • See Argüello and Johansson (2022) for further details of governance related to ice management.
    • Specific to Ice Thickening:
      • Research to date has been on small scales and governed by regional bodies.
      • Desch et al. (2017) argued that since the goal of ice thickening may be to restore Arctic sea ice to a previous state, this technique is more like restoration than geoengineering. Bodansky and Hunt (2020) make a similar argument that localized interventions are more like mitigation and adaptation.

• Here we define justice related to approaches to slow the loss of Arctic sea ice through distributive justice, procedural justice, and restorative justice. Following COMEST (2023), we consider questions of ethics through a justice lens. Note that this is not an exhaustive list of justice dimensions and as the field advances, so will the related considerations and dimensions.
• Distributive justice
  • Applicable to all approaches within Ice Management:
    • If distributive justice is considered, the objective would be that benefits and costs of research or potential deployment of the approach be distributed fairly while protecting the basic rights of the most vulnerable.
  • Specific to Ice Thickening:
    • No additional information.
• Procedural justice
  • Applicable to all approaches within Ice Management:
    • If procedural justice is considered, people affected by research would have an opportunity to participate and have a say in how the approach will be researched, deployed, and governed.
    • Bennett et al. (2022) suggests an inclusive governance approach that incorporates stakeholder concerns in the design and deployment of approaches and effectively communicates risk. Within the development of such a framework there is an opportunity to prioritize Indigenous self-determination and procedural justice (Chuffart et al. 2023). Note, however, that stakeholders may also include non-local people.
  • Specific to Ice Thickening:
    • Some researchers working on this approach have engaged and worked with local people living in research areas.
• Restorative justice
  • Applicable to all approaches within Ice Management:
    • If restorative justice is considered, plans would be developed for those who could be harmed by the approach to be compensated, rehabilitated, or restored.
  • Specific to Ice Thickening:
    • As of the writing of this version, we are not aware of any plans for those who could be harmed by the approach to be compensated, rehabilitated, or restored. There is an argument that ice thickening serves to restore sea ice (Desch et al. 2017), which would potentially make this technique a method for restorative justice to communities suffering from sea ice loss. However, there is not enough knowledge about this approach to know about its potential negative consequences for species and ecosystems and therefore its restoration efficacy.

• Real Ice is working with Indigenous communities in Canada (Ekaluktutiak Hunters & Trappers Organisation).
• Arctic Reflections has given public talks, been featured in a documentary, and is endorsed as a UN Decade of Ocean Science Action.

• Applicable to all approaches within Ice Management:
  • The principle of free, prior, and informed consent (FPIC) in the United Nations Declaration on the Rights of Indigenous Peoples (UNDRIP) is the foundation for engagement with Indigenous Peoples.
  • Particular to any potential Arctic research or deployment, The Inuit Circumpolar Council (2022) has published Circumpolar Inuit Protocols for Equitable and Ethical Engagement, which include eight protocols:
    • ‘Nothing About Us Without Us’ – Always Engage with Inuit
    • Recognize Indigenous Knowledge in its Own Right
    • Practice Good Governance
    • Communication with Intent
    • Exercising Accountability – Building Trust
    • Building Meaningful Partnerships
    • Information, Data Sharing, Ownership, and Permissions
    • Equitably Fund Inuit Representation and Knowledge
  • Any meaningful engagement with Indigenous peoples needs to consider context. Whyte (2018) states, “Indigenous voices should be involved in scientific and policy discussions of different types of geoengineering. But, context matters. Geoengineering discourses cannot just be associated with geoengineering to the exclusion of topics and solutions that Indigenous peoples value.”
• Specific to Ice Thickening:
  • Real Ice is working with Indigenous communities in Canada (Ekaluktutiak Hunters & Trappers Organisation).

• Applicable to all approaches within Ice Management:
  • For all Ice Management approaches, research and testing could be done within national jurisdiction (territorial seas or Exclusive Economic Zones (EEZs); note that different legal rules apply to territorial seas and EEZs). Scalability may require deployment to additional areas within international waters.  See “Existing governance” for other available information on relevant governance structures.
• Specific to Ice Thickening:
  • No additional information.

• Applicable to all approaches within Ice Management:
  • The Arctic Ocean is governed by the United Nations Convention on the Law of the Sea (UNCLOS), which includes all Arctic coastal states except the United States. The United States, however, is bound to customary law “including customs codified or that have emerged from UNCLOS” (Argüello and Johansson 2022).
    • UNCLOS and marine scientific research (MSR):
      • MSR is governed by Part XIII of UNCLOS. In general, the right of states to conduct MSR is subject to the rights and duties of other states under UNCLOS (UNCLOS Article 238). There is a duty on parties to promote and facilitate MSR (UNCLOS Article 239).
      • MSR shall be conducted exclusively for peaceful purposes, it may not unjustifiably interfere with other legitimate uses of the sea, and it must be conducted in compliance with all relevant regulations adopted in conformity with the Convention, including those for the protection and preservation of the marine environment (UNCLOS Article 240).
      • States are responsible and liable for damage caused by pollution of the marine environment arising out of MSR undertaken by them or on their behalf (UNCLOS Article 263(3)).
        • Any approaches that involve adding material or energy to the ocean that would cause or be likely to cause damage to the marine environment would constitute “pollution of the marine environment” within the meaning of Article 1(1)(4) of UNCLOS, and States would have a duty to minimize the pollution pursuant to Article 194.
      • National Jurisdiction and MSR under UNCLOS
        • In a coastal state’s territorial sea (12 nautical miles from shore baseline), the coastal state has the exclusive right to regulate, authorize, and conduct MSR.
        • In a coastal state’s EEZ (200 nautical miles from shore baseline), coastal states also have the right to regulate, authorize, and conduct MSR, and MSR by other states requires the consent of the coastal state (UNCLOS Article 246(2)). States ordinarily give their consent, and they are required to adopt rules to ensure that consent is not delayed or denied unreasonably. UNCLOS further specifies grounds for refusing consent, including if the MSR involves introducing harmful substances into the marine environment (UNCLOS Article 246(5)(b)).
      • Areas outside National Jurisdiction and MSR under UNCLOS
        • On the high seas, UNCLOS provides for freedom of MSR (UNCLOS Article 87(1)(f)), but it must be done with due regard for the interests of other States in their exercise of the freedom of the high seas (Articles 87(2)).
        • The high seas are reserved for peaceful purposes (Article 88) and no state may subject a portion of high seas to its sovereignty (Article 89).
      • The 2017 Agreement on Enhancing Arctic Scientific Cooperation is relevant. This is a legally binding agreement signed in 2017 by all Arctic States negotiated in the Arctic Council. It promotes international cooperation and favorable conditions for conducting scientific research, facilitates access to research areas, infrastructure, and facilities, and promotes education and training of scientists in Arctic issues. The agreement also encourages participants to utilize traditional and local knowledge as appropriate as well as encourages communication between traditional and local knowledge holders and participants. This may provide a framework for consultation with stakeholders including Indigenous peoples in intervention research, planning, and testing (Chuffart et al. 2023).
      • The Arctic Council has been called upon as a venue for providing oversight on approaches to slow the loss of Arctic sea ice, or to establish working groups to provide guidance (Bodansky and Hunt 2020, Bennett et al. 2022). If the objective of the approach is to slow the loss of Arctic sea ice, rather than altering global temperatures, the Arctic parties have the primary interest (Bodansky and Hunt 2020). However, the current geopolitical landscape and lack of participation from Russia makes consensus difficult.
      • See Argüello and Johansson (2022) for further details of governance related to ice management.
    • Specific to Ice Thickening:
      • Research to date has been on small scales and governed by regional bodies.
      • Desch et al. (2017) argued that since the goal of ice thickening may be to restore Arctic sea ice to a previous state, this technique is more like restoration than geoengineering. Bodansky and Hunt (2020) make a similar argument that localized interventions are more like mitigation and adaptation.

• Here we define justice related to approaches to slow the loss of Arctic sea ice through distributive justice, procedural justice, and restorative justice. Following COMEST (2023), we consider questions of ethics through a justice lens. Note that this is not an exhaustive list of justice dimensions and as the field advances, so will the related considerations and dimensions.
• Distributive justice
  • Applicable to all approaches within Ice Management:
    • If distributive justice is considered, the objective would be that benefits and costs of research or potential deployment of the approach be distributed fairly while protecting the basic rights of the most vulnerable.
  • Specific to Ice Thickening:
    • No additional information.
• Procedural justice
  • Applicable to all approaches within Ice Management:
    • If procedural justice is considered, people affected by research would have an opportunity to participate and have a say in how the approach will be researched, deployed, and governed.
    • Bennett et al. (2022) suggests an inclusive governance approach that incorporates stakeholder concerns in the design and deployment of approaches and effectively communicates risk. Within the development of such a framework there is an opportunity to prioritize Indigenous self-determination and procedural justice (Chuffart et al. 2023). Note, however, that stakeholders may also include non-local people.
  • Specific to Ice Thickening:
    • Some researchers working on this approach have engaged and worked with local people living in research areas.
• Restorative justice
  • Applicable to all approaches within Ice Management:
    • If restorative justice is considered, plans would be developed for those who could be harmed by the approach to be compensated, rehabilitated, or restored.
  • Specific to Ice Thickening:
    • As of the writing of this version, we are not aware of any plans for those who could be harmed by the approach to be compensated, rehabilitated, or restored. There is an argument that ice thickening serves to restore sea ice (Desch et al. 2017), which would potentially make this technique a method for restorative justice to communities suffering from sea ice loss. However, there is not enough knowledge about this approach to know about its potential negative consequences for species and ecosystems and therefore its restoration efficacy.

• Real Ice is working with Indigenous communities in Canada (Ekaluktutiak Hunters & Trappers Organisation).
• Arctic Reflections has given public talks, been featured in a documentary, and is endorsed as a UN Decade of Ocean Science Action.

• Applicable to all approaches within Ice Management:
  • The principle of free, prior, and informed consent (FPIC) in the United Nations Declaration on the Rights of Indigenous Peoples (UNDRIP) is the foundation for engagement with Indigenous Peoples.
  • Particular to any potential Arctic research or deployment, The Inuit Circumpolar Council (2022) has published Circumpolar Inuit Protocols for Equitable and Ethical Engagement, which include eight protocols:
    • ‘Nothing About Us Without Us’ – Always Engage with Inuit
    • Recognize Indigenous Knowledge in its Own Right
    • Practice Good Governance
    • Communication with Intent
    • Exercising Accountability – Building Trust
    • Building Meaningful Partnerships
    • Information, Data Sharing, Ownership, and Permissions
    • Equitably Fund Inuit Representation and Knowledge
  • Any meaningful engagement with Indigenous peoples needs to consider context. Whyte (2018) states, “Indigenous voices should be involved in scientific and policy discussions of different types of geoengineering. But, context matters. Geoengineering discourses cannot just be associated with geoengineering to the exclusion of topics and solutions that Indigenous peoples value.”
• Specific to Ice Thickening:
  • Real Ice is working with Indigenous communities in Canada (Ekaluktutiak Hunters & Trappers Organisation).

• Applicable to all approaches within Ice Management:
  • For all Ice Management approaches, research and testing could be done within national jurisdiction (territorial seas or Exclusive Economic Zones (EEZs); note that different legal rules apply to territorial seas and EEZs). Scalability may require deployment to additional areas within international waters.  See “Existing governance” for other available information on relevant governance structures.
• Specific to Ice Thickening:
  • No additional information.

• Applicable to all approaches within Ice Management:
  • The Arctic Ocean is governed by the United Nations Convention on the Law of the Sea (UNCLOS), which includes all Arctic coastal states except the United States. The United States, however, is bound to customary law “including customs codified or that have emerged from UNCLOS” (Argüello and Johansson 2022).
    • UNCLOS and marine scientific research (MSR):
      • MSR is governed by Part XIII of UNCLOS. In general, the right of states to conduct MSR is subject to the rights and duties of other states under UNCLOS (UNCLOS Article 238). There is a duty on parties to promote and facilitate MSR (UNCLOS Article 239).
      • MSR shall be conducted exclusively for peaceful purposes, it may not unjustifiably interfere with other legitimate uses of the sea, and it must be conducted in compliance with all relevant regulations adopted in conformity with the Convention, including those for the protection and preservation of the marine environment (UNCLOS Article 240).
      • States are responsible and liable for damage caused by pollution of the marine environment arising out of MSR undertaken by them or on their behalf (UNCLOS Article 263(3)).
        • Any approaches that involve adding material or energy to the ocean that would cause or be likely to cause damage to the marine environment would constitute “pollution of the marine environment” within the meaning of Article 1(1)(4) of UNCLOS, and States would have a duty to minimize the pollution pursuant to Article 194.
      • National Jurisdiction and MSR under UNCLOS
        • In a coastal state’s territorial sea (12 nautical miles from shore baseline), the coastal state has the exclusive right to regulate, authorize, and conduct MSR.
        • In a coastal state’s EEZ (200 nautical miles from shore baseline), coastal states also have the right to regulate, authorize, and conduct MSR, and MSR by other states requires the consent of the coastal state (UNCLOS Article 246(2)). States ordinarily give their consent, and they are required to adopt rules to ensure that consent is not delayed or denied unreasonably. UNCLOS further specifies grounds for refusing consent, including if the MSR involves introducing harmful substances into the marine environment (UNCLOS Article 246(5)(b)).
      • Areas outside National Jurisdiction and MSR under UNCLOS
        • On the high seas, UNCLOS provides for freedom of MSR (UNCLOS Article 87(1)(f)), but it must be done with due regard for the interests of other States in their exercise of the freedom of the high seas (Articles 87(2)).
        • The high seas are reserved for peaceful purposes (Article 88) and no state may subject a portion of high seas to its sovereignty (Article 89).
      • The 2017 Agreement on Enhancing Arctic Scientific Cooperation is relevant. This is a legally binding agreement signed in 2017 by all Arctic States negotiated in the Arctic Council. It promotes international cooperation and favorable conditions for conducting scientific research, facilitates access to research areas, infrastructure, and facilities, and promotes education and training of scientists in Arctic issues. The agreement also encourages participants to utilize traditional and local knowledge as appropriate as well as encourages communication between traditional and local knowledge holders and participants. This may provide a framework for consultation with stakeholders including Indigenous peoples in intervention research, planning, and testing (Chuffart et al. 2023).
      • The Arctic Council has been called upon as a venue for providing oversight on approaches to slow the loss of Arctic sea ice, or to establish working groups to provide guidance (Bodansky and Hunt 2020, Bennett et al. 2022). If the objective of the approach is to slow the loss of Arctic sea ice, rather than altering global temperatures, the Arctic parties have the primary interest (Bodansky and Hunt 2020). However, the current geopolitical landscape and lack of participation from Russia makes consensus difficult.
      • See Argüello and Johansson (2022) for further details of governance related to ice management.
    • Specific to Ice Thickening:
      • Research to date has been on small scales and governed by regional bodies.
      • Desch et al. (2017) argued that since the goal of ice thickening may be to restore Arctic sea ice to a previous state, this technique is more like restoration than geoengineering. Bodansky and Hunt (2020) make a similar argument that localized interventions are more like mitigation and adaptation.

• Here we define justice related to approaches to slow the loss of Arctic sea ice through distributive justice, procedural justice, and restorative justice. Following COMEST (2023), we consider questions of ethics through a justice lens. Note that this is not an exhaustive list of justice dimensions and as the field advances, so will the related considerations and dimensions.

• Distributive justice
  • Applicable to all approaches within Ice Management:
    • If distributive justice is considered, the objective would be that benefits and costs of research or potential deployment of the approach be distributed fairly while protecting the basic rights of the most vulnerable.
  • Specific to Ice Thickening:
    • No additional information.
• Procedural justice
  • Applicable to all approaches within Ice Management:
    • If procedural justice is considered, people affected by research would have an opportunity to participate and have a say in how the approach will be researched, deployed, and governed.
    • Bennett et al. (2022) suggests an inclusive governance approach that incorporates stakeholder concerns in the design and deployment of approaches and effectively communicates risk. Within the development of such a framework there is an opportunity to prioritize Indigenous self-determination and procedural justice (Chuffart et al. 2023). Note, however, that stakeholders may also include non-local people.
  • Specific to Ice Thickening:
    • Some researchers working on this approach have engaged and worked with local people living in research areas.
• Restorative justice
  • Applicable to all approaches within Ice Management:
    • If restorative justice is considered, plans would be developed for those who could be harmed by the approach to be compensated, rehabilitated, or restored.
  • Specific to Ice Thickening:
    • As of the writing of this version, we are not aware of any plans for those who could be harmed by the approach to be compensated, rehabilitated, or restored. There is an argument that ice thickening serves to restore sea ice (Desch et al. 2017), which would potentially make this technique a method for restorative justice to communities suffering from sea ice loss. However, there is not enough knowledge about this approach to know about its potential negative consequences for species and ecosystems and therefore its restoration efficacy.

• Real Ice is working with Indigenous communities in Canada (Ekaluktutiak Hunters & Trappers Organisation).
• Arctic Reflections has given public talks, been featured in a documentary, and is endorsed as a UN Decade of Ocean Science Action.

• Applicable to all approaches within Ice Management:
  • The principle of free, prior, and informed consent (FPIC) in the United Nations Declaration on the Rights of Indigenous Peoples (UNDRIP) is the foundation for engagement with Indigenous Peoples.
  • Particular to any potential Arctic research or deployment, The Inuit Circumpolar Council (2022) has published Circumpolar Inuit Protocols for Equitable and Ethical Engagement, which include eight protocols:
    • ‘Nothing About Us Without Us’ – Always Engage with Inuit
    • Recognize Indigenous Knowledge in its Own Right
    • Practice Good Governance
    • Communication with Intent
    • Exercising Accountability – Building Trust
    • Building Meaningful Partnerships
    • Information, Data Sharing, Ownership, and Permissions
    • Equitably Fund Inuit Representation and Knowledge
  • Any meaningful engagement with Indigenous peoples needs to consider context. Whyte (2018) states, “Indigenous voices should be involved in scientific and policy discussions of different types of geoengineering. But, context matters. Geoengineering discourses cannot just be associated with geoengineering to the exclusion of topics and solutions that Indigenous peoples value.”
• Specific to Ice Thickening:
  • Real Ice is working with Indigenous communities in Canada (Ekaluktutiak Hunters & Trappers Organisation).

• Applicable to all approaches within Ice Management:
  • For all Ice Management approaches, research and testing could be done within national jurisdiction (territorial seas or Exclusive Economic Zones (EEZs); note that different legal rules apply to territorial seas and EEZs). Scalability may require deployment to additional areas within international waters.  See “Existing governance” for other available information on relevant governance structures.
• Specific to Ice Thickening:
  • No additional information.

• Applicable to all approaches within Ice Management:
  • The Arctic Ocean is governed by the United Nations Convention on the Law of the Sea (UNCLOS), which includes all Arctic coastal states except the United States. The United States, however, is bound to customary law “including customs codified or that have emerged from UNCLOS” (Argüello and Johansson 2022).
    • UNCLOS and marine scientific research (MSR):
      • MSR is governed by Part XIII of UNCLOS. In general, the right of states to conduct MSR is subject to the rights and duties of other states under UNCLOS (UNCLOS Article 238). There is a duty on parties to promote and facilitate MSR (UNCLOS Article 239).
      • MSR shall be conducted exclusively for peaceful purposes, it may not unjustifiably interfere with other legitimate uses of the sea, and it must be conducted in compliance with all relevant regulations adopted in conformity with the Convention, including those for the protection and preservation of the marine environment (UNCLOS Article 240).
      • States are responsible and liable for damage caused by pollution of the marine environment arising out of MSR undertaken by them or on their behalf (UNCLOS Article 263(3)).
        • Any approaches that involve adding material or energy to the ocean that would cause or be likely to cause damage to the marine environment would constitute “pollution of the marine environment” within the meaning of Article 1(1)(4) of UNCLOS, and States would have a duty to minimize the pollution pursuant to Article 194.
      • National Jurisdiction and MSR under UNCLOS
        • In a coastal state’s territorial sea (12 nautical miles from shore baseline), the coastal state has the exclusive right to regulate, authorize, and conduct MSR.
        • In a coastal state’s EEZ (200 nautical miles from shore baseline), coastal states also have the right to regulate, authorize, and conduct MSR, and MSR by other states requires the consent of the coastal state (UNCLOS Article 246(2)). States ordinarily give their consent, and they are required to adopt rules to ensure that consent is not delayed or denied unreasonably. UNCLOS further specifies grounds for refusing consent, including if the MSR involves introducing harmful substances into the marine environment (UNCLOS Article 246(5)(b)).
      • Areas outside National Jurisdiction and MSR under UNCLOS
        • On the high seas, UNCLOS provides for freedom of MSR (UNCLOS Article 87(1)(f)), but it must be done with due regard for the interests of other States in their exercise of the freedom of the high seas (Articles 87(2)).
        • The high seas are reserved for peaceful purposes (Article 88) and no state may subject a portion of high seas to its sovereignty (Article 89).
      • The 2017 Agreement on Enhancing Arctic Scientific Cooperation is relevant. This is a legally binding agreement signed in 2017 by all Arctic States negotiated in the Arctic Council. It promotes international cooperation and favorable conditions for conducting scientific research, facilitates access to research areas, infrastructure, and facilities, and promotes education and training of scientists in Arctic issues. The agreement also encourages participants to utilize traditional and local knowledge as appropriate as well as encourages communication between traditional and local knowledge holders and participants. This may provide a framework for consultation with stakeholders including Indigenous peoples in intervention research, planning, and testing (Chuffart et al. 2023).
      • The Arctic Council has been called upon as a venue for providing oversight on approaches to slow the loss of Arctic sea ice, or to establish working groups to provide guidance (Bodansky and Hunt 2020, Bennett et al. 2022). If the objective of the approach is to slow the loss of Arctic sea ice, rather than altering global temperatures, the Arctic parties have the primary interest (Bodansky and Hunt 2020). However, the current geopolitical landscape and lack of participation from Russia makes consensus difficult.
      • See Argüello and Johansson (2022) for further details of governance related to ice management.
    • Specific to Ice Thickening:
      • Research to date has been on small scales and governed by regional bodies.
      • Desch et al. (2017) argued that since the goal of ice thickening may be to restore Arctic sea ice to a previous state, this technique is more like restoration than geoengineering. Bodansky and Hunt (2020) make a similar argument that localized interventions are more like mitigation and adaptation.

• Here we define justice related to approaches to slow the loss of Arctic sea ice through distributive justice, procedural justice, and restorative justice. Following COMEST (2023), we consider questions of ethics through a justice lens. Note that this is not an exhaustive list of justice dimensions and as the field advances, so will the related considerations and dimensions.

• Distributive justice
  • Applicable to all approaches within Ice Management:
    • If distributive justice is considered, the objective would be that benefits and costs of research or potential deployment of the approach be distributed fairly while protecting the basic rights of the most vulnerable.
  • Specific to Ice Thickening:
    • No additional information.
• Procedural justice
  • Applicable to all approaches within Ice Management:
    • If procedural justice is considered, people affected by research would have an opportunity to participate and have a say in how the approach will be researched, deployed, and governed.
    • Bennett et al. (2022) suggests an inclusive governance approach that incorporates stakeholder concerns in the design and deployment of approaches and effectively communicates risk. Within the development of such a framework there is an opportunity to prioritize Indigenous self-determination and procedural justice (Chuffart et al. 2023). Note, however, that stakeholders may also include non-local people.
  • Specific to Ice Thickening:
    • Some researchers working on this approach have engaged and worked with local people living in research areas.
• Restorative justice
  • Applicable to all approaches within Ice Management:
    • If restorative justice is considered, plans would be developed for those who could be harmed by the approach to be compensated, rehabilitated, or restored.
  • Specific to Ice Thickening:
    • As of the writing of this version, we are not aware of any plans for those who could be harmed by the approach to be compensated, rehabilitated, or restored. There is an argument that ice thickening serves to restore sea ice (Desch et al. 2017), which would potentially make this technique a method for restorative justice to communities suffering from sea ice loss. However, there is not enough knowledge about this approach to know about its potential negative consequences for species and ecosystems and therefore its restoration efficacy.

• Real Ice is working with Indigenous communities in Canada (Ekaluktutiak Hunters & Trappers Organisation).
• Arctic Reflections has given public talks, been featured in a documentary, and is endorsed as a UN Decade of Ocean Science Action.

• Applicable to all approaches within Ice Management:
  • The principle of free, prior, and informed consent (FPIC) in the United Nations Declaration on the Rights of Indigenous Peoples (UNDRIP) is the foundation for engagement with Indigenous Peoples.
  • Particular to any potential Arctic research or deployment, The Inuit Circumpolar Council (2022) has published Circumpolar Inuit Protocols for Equitable and Ethical Engagement, which include eight protocols:
    • ‘Nothing About Us Without Us’ – Always Engage with Inuit
    • Recognize Indigenous Knowledge in its Own Right
    • Practice Good Governance
    • Communication with Intent
    • Exercising Accountability - Building Trust
    • Building Meaningful Partnerships
    • Information, Data Sharing, Ownership and Permissions
    • Equitably Fund Inuit Representation and Knowledge
  • Any meaningful engagement with Indigenous peoples needs to consider context. Whyte (2018) states, “Indigenous voices should be involved in scientific and policy discussions of different types of geoengineering. But, context matters. Geoengineering discourses cannot just be associated with geoengineering to the exclusion of topics and solutions that Indigenous peoples value.”
• Specific to Ice Thickening:
  • Real Ice is working with Indigenous communities in Canada (Ekaluktutiak Hunters & Trappers Organisation).

• Applicable to all approaches within Ice Management:
  • For all Ice Management approaches, research and testing could be done within national jurisdiction (territorial seas or Exclusive Economic Zones (EEZs); note that different legal rules apply to territorial seas and EEZs). Scalability may require deployment to additional areas within international waters.  See “Existing governance” for other available information on relevant governance structures.
• Specific to Ice Thickening:
  • No additional information.

• Applicable to all approaches within Ice Management:
  • The Arctic Ocean is governed by the United Nations Convention on the Law of the Sea (UNCLOS), which includes all Arctic coastal states except the United States. The United States, however, is bound to customary law “including customs codified or that have emerged from UNCLOS” (Argüello and Johansson 2022).
    • UNCLOS and marine scientific research (MSR):
      • MSR is governed by Part XIII of UNCLOS. In general, the right of states to conduct MSR is subject to the rights and duties of other states under UNCLOS (UNCLOS Article 238). There is a duty on parties to promote and facilitate MSR (UNCLOS Article 239).
      • MSR shall be conducted exclusively for peaceful purposes, it may not unjustifiably interfere with other legitimate uses of the sea, and it must be conducted in compliance with all relevant regulations adopted in conformity with the Convention, including those for the protection and preservation of the marine environment (UNCLOS Article 240).
      • States are responsible and liable for damage caused by pollution of the marine environment arising out of MSR undertaken by them or on their behalf (UNCLOS Article 263(3)).
        • Any approaches that involve adding material or energy to the ocean that would cause or be likely to cause damage to the marine environment would constitute “pollution of the marine environment” within the meaning of Article 1(1)(4) of UNCLOS, and States would have a duty to minimize the pollution pursuant to Article 194.
      • National Jurisdiction and MSR under UNCLOS
        • In a coastal state’s territorial sea (12 nautical miles from shore baseline), the coastal state has the exclusive right to regulate, authorize, and conduct MSR.
        • In a coastal state’s EEZ (200 nautical miles from shore baseline), coastal states also have the right to regulate, authorize, and conduct MSR, and MSR by other states requires the consent of the coastal state (UNCLOS Article 246(2)). States ordinarily give their consent, and they are required to adopt rules to ensure that consent is not delayed or denied unreasonably. UNCLOS further specifies grounds for refusing consent, including if the MSR involves introducing harmful substances into the marine environment (UNCLOS Article 246(5)(b)).
      • Areas outside National Jurisdiction and MSR under UNCLOS
        • On the high seas, UNCLOS provides for freedom of MSR (UNCLOS Article 87(1)(f)), but it must be done with due regard for the interests of other States in their exercise of the freedom of the high seas (Articles 87(2)).
        • The high seas are reserved for peaceful purposes (Article 88) and no state may subject a portion of high seas to its sovereignty (Article 89).
      • The 2017 Agreement on Enhancing Arctic Scientific Cooperation is relevant. This is a legally binding agreement signed in 2017 by all Arctic States negotiated in the Arctic Council. It promotes international cooperation and favorable conditions for conducting scientific research, facilitates access to research areas, infrastructure, and facilities, and promotes education and training of scientists in Arctic issues. The agreement also encourages participants to utilize traditional and local knowledge as appropriate as well as encourages communication between traditional and local knowledge holders and participants. This may provide a framework for consultation with stakeholders including Indigenous peoples in intervention research, planning, and testing (Chuffart et al. 2023).
      • The Arctic Council has been called upon as a venue for providing oversight on approaches to slow the loss of Arctic sea ice, or to establish working groups to provide guidance (Bodansky and Hunt 2020, Bennett et al. 2022). If the objective of the approach is to slow the loss of Arctic sea ice, rather than altering global temperatures, the Arctic parties have the primary interest (Bodansky and Hunt 2020). However, the current geopolitical landscape and lack of participation from Russia makes consensus difficult.
      • See Argüello and Johansson (2022) for further details of governance related to ice management.
    • Specific to Ice Thickening:
      • Research to date has been on small scales and governed by regional bodies.
      • Desch et al. (2017) argued that since the goal of ice thickening may be to restore Arctic sea ice to a previous state, this technique is more like restoration than geoengineering. Bodansky and Hunt (2020) make a similar argument that localized interventions are more like mitigation and adaptation.

• Here we define justice related to approaches to slow the loss of Arctic sea ice through distributive justice, procedural justice, and restorative justice. Following COMEST (2023), we consider questions of ethics through a justice lens. Note that this is not an exhaustive list of justice dimensions and as the field advances, so will the related considerations and dimensions.

• Distributive justice
  • Applicable to all approaches within Ice Management:
    • If distributive justice is considered, the objective would be that benefits and costs of research or potential deployment of the approach be distributed fairly while protecting the basic rights of the most vulnerable.
  • Specific to Ice Thickening:
    • No additional information.
• Procedural justice
  • Applicable to all approaches within Ice Management:
    • If procedural justice is considered, people affected by research would have an opportunity to participate and have a say in how the approach will be researched, deployed, and governed.
    • Bennett et al. (2022) suggests an inclusive governance approach that incorporates stakeholder concerns in the design and deployment of approaches and effectively communicates risk. Within the development of such a framework there is an opportunity to prioritize Indigenous self-determination and procedural justice (Chuffart et al. 2023). Note, however, that stakeholders may also include non-local people.
  • Specific to Ice Thickening:
    • Some researchers working on this approach have engaged and worked with local people living in research areas.
• Restorative justice
  • Applicable to all approaches within Ice Management:
    • If restorative justice is considered, plans would be developed for those who could be harmed by the approach to be compensated, rehabilitated, or restored.
  • Specific to Ice Thickening:
    • As of the writing of this version, we are not aware of any plans for those who could be harmed by the approach to be compensated, rehabilitated, or restored. There is an argument that ice thickening serves to restore sea ice (Desch et al. 2017), which would potentially make this technique a method for restorative justice to communities suffering from sea ice loss. However, there is not enough knowledge about this approach to know about its potential negative consequences for species and ecosystems and therefore its restoration efficacy.

• Real Ice is working with Indigenous communities in Canada (Ekaluktutiak Hunters & Trappers Organisation).
• Arctic Reflections has given public talks, been featured in a documentary, and is endorsed as a UN Decade of Ocean Science Action.

• Applicable to all approaches within Ice Management:
  • The principle of free, prior and informed consent (FPIC) in the United Nations Declaration on the Rights of Indigenous Peoples (UNDRIP) is the foundation for engagement with Indigenous Peoples.
  • Particular to any potential Arctic research or deployment, The Inuit Circumpolar Council (2022) has published Circumpolar Inuit Protocols for Equitable and Ethical Engagement, which include eight protocols:
    • ‘Nothing About Us Without Us’ – Always Engage with Inuit
    • Recognize Indigenous Knowledge in its Own Right
    • Practice Good Governance
    • Communication with Intent
    • Exercising Accountability - Building Trust
    • Building Meaningful Partnerships
    • Information, Data Sharing, Ownership and Permissions
    • Equitably Fund Inuit Representation and Knowledge
  • Any meaningful engagement with Indigenous peoples needs to consider context. Whyte (2018) states, “Indigenous voices should be involved in scientific and policy discussions of different types of geoengineering. But, context matters. Geoengineering discourses cannot just be associated with geoengineering to the exclusion of topics and solutions that Indigenous peoples value.”
• Specific to Ice Thickening:
  • Real Ice is working with Indigenous communities in Canada (Ekaluktutiak Hunters & Trappers Organisation).