• Black carbon is an aerosol that warms the climate and is a component of fine particulate matter, PM₅. Black carbon enters the atmosphere through incomplete combustion of fossil fuels, as well as biofuels and biomass (Zaelke et al. 2023). In the atmosphere, black carbon adsorbs and scatters shortwave radiation and has a warming effect (Bond et al. 2013). Black carbon deposition also impacts the Arctic by darkening snow and ice, reducing albedo. Black carbon emissions in the Arctic influence black carbon concentrations near the surface (deposition at surface and in the lower troposphere), while emissions outside of the Arctic largely control the black carbon concentrations at higher altitudes (Kühn et al. 2020). The emissions lower in the atmosphere in the Arctic have a strong warming effect and also have a higher likelihood of falling on ice and snow and reducing the albedo (Flanner 2013).
• Black carbon emissions contribute to 20% of the global shipping industry’s impact on temperature increases (the rest is attributed to CO₂; Olmer et al. 2017), and shipping in the Arctic has risen substantially (Comer et al. 2020, PAME 2024), and is expected to continue to rise as climate change continues and the melting of Arctic sea ice opens up new opportunities for shipping. The International Council on Clean Transportation (ICCT) estimated that black carbon emissions from shipping within the IMO (International Maritime Organization) Arctic waters doubled from 2015 to 2021 – although other sources estimate smaller changes, potentially due to differences in assumptions around the global 2020 sulfur cap (Matthews et al. 2023).
• Globally, targeted measures for reducing black carbon emissions could result in a 70% reduction by 2030 (Zaelke et al. 2023). These measures include 1) rapid ratification of the Gothenburg Protocol and 2012 amendment with controls for black carbon, 2) reducing diesel emissions by mandating diesel particulate filters, eliminating diesel and high-emitting vehicles, and shifting to clean forms of transportation, 3) Eliminating flaring and switching to clean energy, 4) switching to clean cooking and heating methods, and 5) banning heavy fuel oil in the Arctic and establishing black carbon emissions standards for vessels (Annex VI of the International Convention for the Prevention of Pollution from Ships (MARPOL); Zaelke et al. 2023).
• Specific to the shipping sector in the Arctic, Zhang et al. (2019) provides a table of potential black carbon mitigation measures focusing on technical and operational solutions. Technical solutions try to improve energy efficiency of ships via technology changes, whereas operational solutions try to reduce air emission via lower cost measures implemented under a management tool, the Ship Energy Efficiency Management Plan (Zhang et al. 2019). Examples of technical solutions include vessel design, fuel treatment, and alternative fuels (Zhang et al. 2019). Examples of operational solutions include weather routing, auto-pilot upgrades, and engine maintenance (Zhang et al. 2019).
• The International Maritime Organization (IMO) has highlighted a short list of six black carbon abatement options to reduce black carbon emissions from shipping, including switching to alternative fuels, adding filters or scrubbers, changing vessel or engine design, and modifying speeds and engine usage (IMO 2015). The IMO also issued a resolution calling for voluntary black carbon emissions from shipping in the Arctic by switching to cleaner fuels or other methods of propulsion (IMO 2021). The Clean Arctic Alliance (CAA) also offers a pathway over the next five years to regulate black carbon emissions from shipping, with suggested mechanisms for implementation. Additionally, CAA issues caution on some measures on the IMO short list, including liquified natural gas and scrubbers, due to other environmental side effects.

• Reducing black carbon emissions will decrease solar absorption in the atmosphere and may increase albedo of sea ice and snow in the Arctic following deposition.
  • Different proposed measures will operate in different ways specific to the measure, but the overall expected impact of reducing black carbon emissions is to decrease solar absorption in the atmosphere and prevent declines in albedo of sea ice and snow in the Arctic as less black carbon accumulates.

• Throughout the globe and Arctic Ocean. The area of the Arctic Ocean is 14,060,000 km².

• Shipping operations at the sea surface, oil and gas operations at the land and sea surface.

• While global measures may reduce black carbon, targeted measures in the Arctic will have the greatest impact. This is largely due to black carbon emitted in the Arctic remains low in the atmosphere (Kühn et al. 2020) and is more likely to settle onto snow and ice.
  • Zhang et al. (2019) reviews potential black carbon mitigation measures for Arctic shipping.

• All year
  • Black carbon is emitted all year and emissions can accumulate over time. The biggest impact on albedo of snow and ice is during the summer, however, the biggest anthropogenic burdens of black carbon in the troposphere (not from forest fires) accumulate during winter (Kühn et al. 2020).

• Black carbon is an aerosol that warms the climate and is a component of fine particulate matter, PM₅. Black carbon enters the atmosphere through incomplete combustion of fossil fuels, as well as biofuels and biomass (Zaelke et al. 2023). In the atmosphere, black carbon adsorbs and scatters shortwave radiation and has a warming effect (Bond et al. 2013). Black carbon deposition also impacts the Arctic by darkening snow and ice, reducing albedo. Black carbon emissions in the Arctic influence black carbon concentrations near the surface (deposition at surface and in the lower troposphere), while emissions outside of the Arctic largely control the black carbon concentrations at higher altitudes (Kühn et al. 2020). The emissions lower in the atmosphere in the Arctic have a strong warming effect and also have a higher likelihood of falling on ice and snow and reducing the albedo (Flanner 2013).
• Black carbon emissions contribute to 20% of the global shipping industry’s impact on temperature increases (the rest is attributed to CO₂; Olmer et al. 2017), and shipping in the Arctic has risen substantially (Comer et al. 2020, PAME 2024), and is expected to continue to rise as climate change continues and the melting of Arctic sea ice opens up new opportunities for shipping. The International Council on Clean Transportation (ICCT) estimated that black carbon emissions from shipping within the IMO (International Maritime Organization) Arctic waters doubled from 2015 to 2021 – although other sources estimate smaller changes, potentially due to differences in assumptions around the global 2020 sulfur cap (Matthews et al. 2023).
• Globally, targeted measures for reducing black carbon emissions could result in a 70% reduction by 2030 (Zaelke et al. 2023). These measures include 1) rapid ratification of the Gothenburg Protocol and 2012 amendment with controls for black carbon, 2) reducing diesel emissions by mandating diesel particulate filters, eliminating diesel and high-emitting vehicles, and shifting to clean forms of transportation, 3) Eliminating flaring and switching to clean energy, 4) switching to clean cooking and heating methods, and 5) banning heavy fuel oil in the Arctic and establishing black carbon emissions standards for vessels (Annex VI of the International Convention for the Prevention of Pollution from Ships (MARPOL); Zaelke et al. 2023).
• Specific to the shipping sector in the Arctic, Zhang et al. (2019) provides a table of potential black carbon mitigation measures focusing on technical and operational solutions. Technical solutions try to improve energy efficiency of ships via technology changes, whereas operational solutions try to reduce air emission via lower cost measures implemented under a management tool, the Ship Energy Efficiency Management Plan (Zhang et al. 2019). Examples of technical solutions include vessel design, fuel treatment, and alternative fuels (Zhang et al. 2019). Examples of operational solutions include weather routing, auto-pilot upgrades, and engine maintenance (Zhang et al. 2019).
• The International Maritime Organization (IMO) has highlighted a short list of six black carbon abatement options to reduce black carbon emissions from shipping, including switching to alternative fuels, adding filters or scrubbers, changing vessel or engine design, and modifying speeds and engine usage (IMO 2015). The IMO also issued a resolution calling for voluntary black carbon emissions from shipping in the Arctic by switching to cleaner fuels or other methods of propulsion (IMO 2021). The Clean Arctic Alliance (CAA) also offers a pathway over the next five years to regulate black carbon emissions from shipping, with suggested mechanisms for implementation. Additionally, CAA issues caution on some measures on the IMO short list, including liquified natural gas and scrubbers, due to other environmental side effects.

• Reducing black carbon emissions will decrease solar absorption in the atmosphere and may increase albedo of sea ice and snow in the Arctic following deposition.
  • Different proposed measures will operate in different ways specific to the measure, but the overall expected impact of reducing black carbon emissions is to decrease solar absorption in the atmosphere and prevent declines in albedo of sea ice and snow in the Arctic as less black carbon accumulates.

• Throughout the globe and Arctic Ocean. The area of the Arctic Ocean is 14,060,000 km².

• Shipping operations at the sea surface, oil and gas operations at the land and sea surface.

• While global measures may reduce black carbon, targeted measures in the Arctic will have the greatest impact. This is largely due to black carbon emitted in the Arctic remains low in the atmosphere (Kühn et al. 2020) and is more likely to settle onto snow and ice.
  • Zhang et al. (2019) reviews potential black carbon mitigation measures for Arctic shipping.

• All year
  • Black carbon is emitted all year and emissions can accumulate over time. The biggest impact on albedo of snow and ice is during the summer, however, the biggest anthropogenic burdens of black carbon in the troposphere (not from forest fires) accumulate during winter (Kühn et al. 2020).

• Black carbon is an aerosol that warms the climate and is a component of fine particulate matter, PM₅. Black carbon enters the atmosphere through incomplete combustion of fossil fuels, as well as biofuels and biomass (Zaelke et al. 2023). In the atmosphere, black carbon adsorbs and scatters shortwave radiation and has a warming effect (Bond et al. 2013). Black carbon deposition also impacts the Arctic by darkening snow and ice, reducing albedo. Black carbon emissions in the Arctic influence black carbon concentrations near the surface (deposition at surface and in the lower troposphere), while emissions outside of the Arctic largely control the black carbon concentrations at higher altitudes (Kühn et al. 2020). The emissions lower in the atmosphere in the Arctic have a strong warming effect and also have a higher likelihood of falling on ice and snow and reducing the albedo (Flanner 2013).
• Black carbon emissions contribute to 20% of the global shipping industry’s impact on temperature increases (the rest is attributed to CO₂; Olmer et al. 2017), and shipping in the Arctic has risen substantially (Comer et al. 2020, PAME 2024), and is expected to continue to rise as climate change continues and the melting of Arctic sea ice opens up new opportunities for shipping. The International Council on Clean Transportation (ICCT) estimated that black carbon emissions from shipping within the IMO (International Maritime Organization) Arctic waters doubled from 2015 to 2021 – although other sources estimate smaller changes, potentially due to differences in assumptions around the global 2020 sulfur cap (Matthews et al. 2023).
• Globally, targeted measures for reducing black carbon emissions could result in a 70% reduction by 2030 (Zaelke et al. 2023). These measures include 1) rapid ratification of the Gothenburg Protocol and 2012 amendment with controls for black carbon, 2) reducing diesel emissions by mandating diesel particulate filters, eliminating diesel and high-emitting vehicles, and shifting to clean forms of transportation, 3) Eliminating flaring and switching to clean energy, 4) switching to clean cooking and heating methods, and 5) banning heavy fuel oil in the Arctic and establishing black carbon emissions standards for vessels (Annex VI of the International Convention for the Prevention of Pollution from Ships (MARPOL); Zaelke et al. 2023).
• Specific to the shipping sector in the Arctic, Zhang et al. (2019) provides a table of potential black carbon mitigation measures focusing on technical and operational solutions. Technical solutions try to improve energy efficiency of ships via technology changes, whereas operational solutions try to reduce air emission via lower cost measures implemented under a management tool, the Ship Energy Efficiency Management Plan (Zhang et al. 2019). Examples of technical solutions include vessel design, fuel treatment, and alternative fuels (Zhang et al. 2019). Examples of operational solutions include weather routing, auto-pilot upgrades, and engine maintenance (Zhang et al. 2019).
• The International Maritime Organization (IMO) has highlighted a short list of six black carbon abatement options to reduce black carbon emissions from shipping, including switching to alternative fuels, adding filters or scrubbers, changing vessel or engine design, and modifying speeds and engine usage (IMO 2015). The IMO also issued a resolution calling for voluntary black carbon emissions from shipping in the Arctic by switching to cleaner fuels or other methods of propulsion (IMO 2021). The Clean Arctic Alliance (CAA) also offers a pathway over the next five years to regulate black carbon emissions from shipping, with suggested mechanisms for implementation. Additionally, CAA issues caution on some measures on the IMO short list, including liquified natural gas and scrubbers, due to other environmental side effects.

• Reducing black carbon emissions will decrease solar absorption in the atmosphere and may increase albedo of sea ice and snow in the Arctic following deposition.
  • Different proposed measures will operate in different ways specific to the measure, but the overall expected impact of reducing black carbon emissions is to decrease solar absorption in the atmosphere and prevent declines in albedo of sea ice and snow in the Arctic as less black carbon accumulates.

• Throughout the globe and Arctic Ocean. The area of the Arctic Ocean is 14,060,000 km².

• Shipping operations at the sea surface, oil and gas operations at the land and sea surface.

• While global measures may reduce black carbon, targeted measures in the Arctic will have the greatest impact. This is largely due to black carbon emitted in the Arctic remains low in the atmosphere (Kühn et al. 2020) and is more likely to settle onto snow and ice.
  • Zhang et al. (2019) reviews potential black carbon mitigation measures for Arctic shipping.

• All year
  • Black carbon is emitted all year and emissions can accumulate over time. The biggest impact on albedo of snow and ice is during the summer, however, the biggest anthropogenic burdens of black carbon in the troposphere (not from forest fires) accumulate during winter (Kühn et al. 2020).

Impact on

• Uncertain, estimates range from 0-0.025
  • Current impact of black carbon emissions on sea ice albedo is albedo reduction of 0-0.004 (AMAP 2021 full report). Reductions in albedo on snow in the Arctic range from 0-0.025 (Bond et al. 2013).

• Global
  • Increase of 0.05°C – decrease of 0.02°C
    • Simulations of global black carbon emissions reductions produce a range of outcomes for global mean temperatures from warming of 0.05°C to cooling of 0.02°C by 2030 (Harmsen et al. 2020). There are large uncertainties in the impact of global reductions of black carbon due to cloud-aerosol interactions, and the impacts are difficult to assess (van Wijngaarden et al. 2023). Black carbon emissions reductions are not expected to have a global impact by 2050 (Harmsen et al. 2020).
• Arctic region
  • Decreases up to 0.258°C by 2050
    • Black carbon emissions reductions could lead to temperature reductions in the Arctic of 0.141°C by 2030, 0.258°C by 2050 compared to 2015 (AMAP 2021 full report).

• Global
  • Decreases in direct shortwave radiative forcing up to 0.57 W/m² for 2050; impacts on effective (total) radiative forcing uncertain
    • Maximum reduction in black carbon emissions would lead to decreases in direct shortwave radiative forcing of 0.45 W/m² for 2030 and 0.57 W/m² for 2050 compared to 2010 (Kühn et al. 2020). However, predictions of decreases in total radiative forcing are variable due to cloud-aerosol interactions; the direct radiative effects due to black carbon emission reductions can be counteracted by cloud effects (Kühn et al. 2020).
    • In 2015, global radiative forcing from black carbon was 0.40 ± 0.13 W/m² (AMAP 2021 full report).
• Arctic region
  • Decreases in direct shortwave radiative forcing up to 0.4 W/m²; impacts on effective (total) radiative forcing uncertain
    • Maximum reductions in direct radiative forcing in the Arctic of 0.4 W/m² possible in Arctic with global emissions reduction of black carbon (Kühn et al. 2020). Effective radiative forcing in the Arctic is highly variable due to variability in cloud cover and uncertainties due to cloud cover, surface albedo, aerosol burdens, cloud droplet number concentration, and heat transport (Kühn et al. 2020).
    • The current impact of black carbon emissions on instantaneous radiative forcing of Arctic sea ice is 0.5 W/m² (AMAP 2021 full report).

• Direct or indirect impact on sea ice?
  • Direct and indirect
    • Black carbon emissions reductions could directly impact sea ice by reducing deposition of black carbon on sea ice, thereby preventing decreases in albedo.
    • Black carbon emissions reductions could indirectly impact sea ice by decreasing warming in the lower troposphere that occurs from the presence of black carbon.
• New or old ice?
  • Both
• Impact on sea ice
  • Unknown
    • No published studies found linking black carbon concentrations to sea ice extent or other sea ice parameters beyond albedo.

Scalability

• Likely scalable
  • Reductions in black carbon emissions of Arctic Council member states could have an outsized impact. Although these emission reductions comprise only about 5% of globally feasible reductions, deposition of black carbon in the Arctic would be reduced by 29.3% (2030) and 33.8% (2050), which corresponds to close to 60% of the achievable decrease in deposition of black carbon in the Arctic via global implementation of reductions (Kühn et al. 2020).

• Unknown

• < 10 years
  • Most mitigation strategies exist and could be deployed if appropriate policies were put in place (van Wijngaarden et al. 2023). The Clean Arctic Alliance offers a pathway over the next five years to regulate black carbon emissions from ships.

• Possible within 20 years
  • Once emissions reductions are implemented black carbon concentrations decrease rapidly (Bond et al. 2013, Kühn et al. 2020).

• Possible within 20 years
  • Once emissions reductions are implemented black carbon concentrations decrease rapidly (Bond et al. 2013, Kühn et al. 2020).

Cost

• $8-50 million per year
  • The estimated cost to achieve a 60% reduction in black carbon emissions reductions in Arctic shipping is $8-50 million per year (Corbett et al. 2010). These numbers are likely outdated due to changes in shipping regulations, so there is a need for updated cost estimates.

• Unknown, however, reducing black carbon emissions would reduce carbon footprint overall
  • Reductions in black carbon of 60% for Arctic shipping would avoid 9-70 million metric tons CO₂ eq per year (Corbett et al. 2010).

Impact on

• Uncertain, estimates range from 0-0.025
  • Current impact of black carbon emissions on sea ice albedo is albedo reduction of 0-0.004 (AMAP 2021 full report). Reductions in albedo on snow in the Arctic range from 0-0.025 (Bond et al. 2013).

• Global
  • Increase of 0.05°C – decrease of 0.02°C
    • Simulations of global black carbon emissions reductions produce a range of outcomes for global mean temperatures from warming of 0.05°C to cooling of 0.02°C by 2030 (Harmsen et al. 2020). There are large uncertainties in the impact of global reductions of black carbon due to cloud-aerosol interactions, and the impacts are difficult to assess (van Wijngaarden et al. 2023). Black carbon emissions reductions are not expected to have a global impact by 2050 (Harmsen et al. 2020).
• Arctic region
  • Decreases up to 0.258°C by 2050
    • Black carbon emissions reductions could lead to temperature reductions in the Arctic of 0.141°C by 2030, 0.258°C by 2050 compared to 2015 (AMAP 2021 full report).

• Global
  • Decreases in direct shortwave radiative forcing up to 0.57 W/m² for 2050; impacts on effective (total) radiative forcing uncertain
    • Maximum reduction in black carbon emissions would lead to decreases in direct shortwave radiative forcing of 0.45 W/m² for 2030 and 0.57 W/m² for 2050 compared to 2010 (Kühn et al. 2020). However, predictions of decreases in total radiative forcing are variable due to cloud-aerosol interactions; the direct radiative effects due to black carbon emission reductions can be counteracted by cloud effects (Kühn et al. 2020).
    • In 2015, global radiative forcing from black carbon was 0.40 ± 0.13 W/m² (AMAP 2021 full report).
• Arctic region
  • Decreases in direct shortwave radiative forcing up to 0.4 W/m²; impacts on effective (total) radiative forcing uncertain
    • Maximum reductions in direct radiative forcing in the Arctic of 0.4 W/m² possible in Arctic with global emissions reduction of black carbon (Kühn et al. 2020). Effective radiative forcing in the Arctic is highly variable due to variability in cloud cover and uncertainties due to cloud cover, surface albedo, aerosol burdens, cloud droplet number concentration, and heat transport (Kühn et al. 2020).
    • The current impact of black carbon emissions on instantaneous radiative forcing of Arctic sea ice is 0.5 W/m² (AMAP 2021 full report).

• Direct or indirect impact on sea ice?
  • Direct and indirect
    • Black carbon emissions reductions could directly impact sea ice by reducing deposition of black carbon on sea ice, thereby preventing decreases in albedo.
    • Black carbon emissions reductions could indirectly impact sea ice by decreasing warming in the lower troposphere that occurs from the presence of black carbon.
• New or old ice?
  • Both
• Impact on sea ice
  • Unknown
    • No published studies found linking black carbon concentrations to sea ice extent or other sea ice parameters beyond albedo.

Scalability

• Likely scalable
  • Reductions in black carbon emissions of Arctic Council member states could have an outsized impact. Although these emission reductions comprise only about 5% of globally feasible reductions, deposition of black carbon in the Arctic would be reduced by 29.3 % (2030) and 33.8 % (2050), which corresponds to close to 60% of the achievable decrease in deposition of black carbon in the Arctic via global implementation of reductions (Kühn et al. 2020).

• Unknown

• < 10 years
  • Most mitigation strategies exist and could be deployed if appropriate policies were put in place (van Wijngaarden et al. 2023). The Clean Arctic Alliance offers a pathway over the next five years to regulate black carbon emissions from ships.

• Possible within 20 years
  • Once emissions reductions are implemented black carbon concentrations decrease rapidly (Bond et al. 2013, Kühn et al. 2020).

• Possible within 20 years
  • Once emissions reductions are implemented black carbon concentrations decrease rapidly (Bond et al. 2013, Kühn et al. 2020).

Cost

• $8-50 million per year
  • The estimated cost to achieve a 60% reduction in black carbon emissions reductions in Arctic shipping is $8-50 million per year (Corbett et al. 2010). These numbers are likely outdated due to changes in shipping regulations, so there is a need for updated cost estimates.

• Unknown, however, reducing black carbon emissions would reduce carbon footprint overall
  • Reductions in black carbon of 60% for Arctic shipping would avoid 9-70 million metric tons CO₂ eq per year (Corbett et al. 2010).

Impact on

• Uncertain, estimates range from 0-0.025
  • Current impact of black carbon emissions on sea ice albedo is albedo reduction of 0-0.004 (AMAP 2021 full report). Reductions in albedo on snow in the Arctic range from 0-0.025 (Bond et al. 2013).

• Global
  • Increase of 0.05°C – decrease of 0.02°C
    • Simulations of global black carbon emissions reductions produce a range of outcomes for global mean temperatures from warming of 0.05°C to cooling of 0.02°C by 2030 (Harmsen et al. 2020). There are large uncertainties in the impact of global reductions of black carbon due to cloud-aerosol interactions, and the impacts are difficult to assess (van Wijngaarden et al. 2023).
• Arctic region
  • Decreases up to 0.258°C by 2050
    • Black carbon emissions reductions could lead to temperature reductions in the Arctic of 0.141°C by 2030, 0.258°C by 2050 compared to 2015 (AMAP 2021 full report).

• Global
  • Decreases in direct shortwave radiative forcing up to 0.57 W/m² for 2050; impacts on effective (total) radiative forcing uncertain
    • Maximum reduction in black carbon emissions would lead to decreases in direct shortwave radiative forcing of 0.45 W/m² for 2030 and 0.57 W/m² for 2050 compared to 2010 (Kühn et al. 2020). However, predictions of decreases in total radiative forcing are variable due to cloud-aerosol interactions; the direct radiative effects due to black carbon emission reductions can be counteracted by cloud effects (Kühn et al. 2020).
    • In 2015, global radiative forcing from black carbon was 0.40 ± 0.13 W/m² (AMAP 2021 full report).
• Arctic region
  • Decreases in direct shortwave radiative forcing up to 0.4 W/m²; impacts on effective (total) radiative forcing uncertain
    • Maximum reductions in direct radiative forcing in the Arctic of 0.4 W/m² possible in Arctic with global emissions reduction of black carbon (Kühn et al. 2020). Effective radiative forcing in the Arctic is highly variable due to variability in cloud cover and uncertainties due to cloud cover, surface albedo, aerosol burdens, cloud droplet number concentration, and heat transport (Kühn et al. 2020).
    • The current impact of black carbon emissions on instantaneous radiative forcing of Arctic sea ice is 0.5 W/m² (AMAP 2021 full report).

• Direct or indirect impact on sea ice?
  • Direct and indirect
    • Black carbon emissions reductions could directly impact sea ice by reducing deposition of black carbon on sea ice, thereby preventing decreases in albedo.
    • Black carbon emissions reductions could indirectly impact sea ice by decreasing warming in the lower troposphere that occurs from the presence of black carbon.
• New or old ice?
  • Both
• Impact on sea ice
  • Unknown
    • No published studies found linking black carbon concentrations to sea ice extent or other sea ice parameters beyond albedo.

Scalability

• Likely scalable
  • Reductions in black carbon emissions of Arctic Council member states could have an outsized impact. Although these emission reductions comprise only about 5% of globally feasible reductions, deposition of black carbon in the Arctic would be reduced by 29.3 % (2030) and 33.8 % (2050), which corresponds to close to 60% of the achievable decrease in deposition of black carbon in the Arctic via global implementation of reductions (Kühn et al. 2020).

• Unknown

• < 10 years
  • Most mitigation strategies exist and could be deployed if appropriate policies were put in place (van Wijngaarden et al. 2023). The Clean Arctic Alliance offers a pathway over the next five years to regulate black carbon emissions from ships.

• Possible within 20 years
  • Once emissions reductions are implemented black carbon concentrations decrease rapidly (Bond et al. 2013, Kühn et al. 2020).

• Possible within 20 years
  • Once emissions reductions are implemented black carbon concentrations decrease rapidly (Bond et al. 2013, Kühn et al. 2020).

Cost

• $8-50 million per year
  • The estimated cost to achieve a 60% reduction in black carbon emissions reductions in Arctic shipping is $8-50 million per year (Corbett et al. 2010). These numbers are likely outdated due to changes in shipping regulations, so there is a need for updated cost estimates.

• Unknown, however, reducing black carbon emissions would reduce carbon footprint overall
  • Reductions in black carbon of 60% for Arctic shipping would avoid 9-70 million metric tons CO₂ eq per year (Corbett et al. 2010).

Impact on

• Uncertain, estimates range from 0-0.025
  • Current impact of black carbon emissions on sea ice albedo is albedo reduction of 0-0.004 (AMAP 2021 full report). Reductions in albedo on snow in the Arctic range from 0-0.025 (Bond et al. 2013).

• Global
  • Increase of 0.05°C – decrease of 0.02°C
    • Simulations of global black carbon emissions reductions produce a range of outcomes for global mean temperatures from warming of 0.05°C to cooling of 0.02°C by 2030 (Harmsen et al. 2020). There are large uncertainties in the impact of global reductions of black carbon due to cloud-aerosol interactions, and the impacts are difficult to assess (van Wijngaarden et al. 2023).
• Arctic region
  • Decreases up to 0.258°C by 2050
    • Black carbon emissions reductions could lead to temperature reductions in the Arctic of 0.141°C by 2030, 0.258°C by 2050 compared to 2015 (AMAP 2021 full report).

• Global
  • Decreases in direct shortwave radiative forcing up to 0.57 W/m² for 2050; impacts on effective (total) radiative forcing uncertain
    • Maximum reduction in black carbon emissions would lead to decreases in direct shortwave radiative forcing of 0.45 W/m² for 2030 and 0.57 W/m² for 2050 compared to 2010 (Kühn et al. 2020). However, predictions of decreases in total radiative forcing are variable due to cloud-aerosol interactions; the direct radiative effects due to black carbon emission reductions can be counteracted by cloud effects (Kühn et al. 2020).
    • In 2015, global radiative forcing from black carbon was 0.40 ± 0.13 W/m² (AMAP 2021 full report).
• Arctic region
  • Decreases in direct shortwave radiative forcing up to 0.4 W/m²; impacts on effective (total) radiative forcing uncertain
    • Maximum reductions in direct radiative forcing in the Arctic of 0.4 W/m² possible in Arctic with global emissions reduction of black carbon (Kühn et al. 2020). Effective radiative forcing in the Arctic is highly variable due to variability in cloud cover and uncertainties due to cloud cover, surface albedo, aerosol burdens, cloud droplet number concentration, and heat transport (Kühn et al. 2020).
    • The current impact of black carbon emissions on instantaneous radiative forcing of Arctic sea ice is 0.5 W/m² (AMAP 2021 full report).

• Direct or indirect impact on sea ice?
  • Direct and indirect
    • Black carbon emissions reductions could directly impact sea ice by reducing deposition of black carbon on sea ice, thereby preventing decreases in albedo.
    • Black carbon emissions reductions could indirectly impact sea ice by decreasing warming in the lower troposphere that occurs from the presence of black carbon.
• New or old ice?
  • Both
• Impact on sea ice
  • Unknown
    • No published studies found linking black carbon concentrations to sea ice extent or other sea ice parameters beyond albedo.

Scalability

• Likely scalable
  • Reductions in black carbon emissions of Arctic Council member states could have an outsized impact. Although these emission reductions comprise only about 5% of globally feasible reductions, deposition of black carbon in the Arctic would be reduced by 29.3 % (2030) and 33.8 % (2050), which corresponds to close to 60% of the achievable decrease in deposition of black carbon in the Arctic via global implementation of reductions (Kühn et al. 2020).

• Unknown

• < 10 years
  • Most mitigation strategies exist and could be deployed if appropriate policies were put in place (van Wijngaarden et al. 2023). The Clean Arctic Alliance offers a pathway over the next five years to regulate black carbon emissions from ships.

• Possible within 20 years
  • Once emissions reductions are implemented black carbon concentrations decrease rapidly (Bond et al. 2013, Kühn et al. 2020).

• Possible within 20 years
  • Once emissions reductions are implemented black carbon concentrations decrease rapidly (Bond et al. 2013, Kühn et al. 2020).

Cost

• $8-50 million per year
  • The estimated cost to achieve a 60% reduction in black carbon emissions reductions in Arctic shipping is $8-50 million per year (Corbett et al. 2010). These numbers are likely outdated due to changes in shipping regulations, so there is a need for updated cost estimates.

• Unknown, however, reducing black carbon emissions would reduce carbon footprint overall
  • Reductions in black carbon of 60% for Arctic shipping would avoid 9-70 million metric tons CO₂ eq per year (Corbett et al. 2010).

Impact on

• Uncertain, estimates range from 0-0.025
  • Current impact of black carbon emissions on sea ice albedo is albedo reduction of 0-0.004 (AMAP 2021 full report). Reductions in albedo on snow in the Arctic range from 0-0.025 (Bond et al. 2013).

• Global
  • Increase of 0.05°C – decrease of 0.02°C
    • Simulations of global black carbon emissions reductions produce a range of outcomes for global mean temperatures from warming of 0.05°C to cooling of 0.02°C by 2030 (Harmsen et al. 2020). There are large uncertainties in the impact of global reductions of black carbon due to cloud-aerosol interactions, and the impacts are difficult to assess (van Wijngaarden et al. 2023).
• Arctic region
  • Decreases up to 0.258°C by 2050
    • Black carbon emissions reductions could lead to temperature reductions in the Arctic of 0.141°C by 2030, 0.258°C by 2050 compared to 2015 (AMAP 2021 full report).

• Global
  • Decreases in direct shortwave radiative forcing up to 0.57 W/m² for 2050; impacts on effective (total) radiative forcing uncertain
    • Maximum reduction in black carbon emissions would lead to decreases in direct shortwave radiative forcing of 0.45 W/m² for 2030 and 0.57 W/m² for 2050 compared to 2010 (Kühn et al. 2020). However, predictions of decreases in total radiative forcing are variable due to cloud-aerosol interactions; the direct radiative effects due to black carbon emission reductions can be counteracted by cloud effects (Kühn et al. 2020).
    • In 2015, global radiative forcing from black carbon was 0.40 ±13 W/m² (AMAP 2021 full report).
• Arctic region
  • Decreases in direct shortwave radiative forcing up to 0.4 W/m²; impacts on effective (total) radiative forcing uncertain
    • Maximum reductions in direct radiative forcing in the Arctic of 0.4 W/m² possible in Arctic with global emissions reduction of black carbon (Kühn et al. 2020). Effective radiative forcing in the Arctic is highly variable due to variability in cloud cover and uncertainties due to cloud cover, surface albedo, aerosol burdens, cloud droplet number concentration, and heat transport (Kühn et al. 2020).
    • The current impact of black carbon emissions on instantaneous radiative forcing of Arctic sea ice is 0.5 W/m² (AMAP 2021 full report).

• Direct or indirect impact on sea ice?
  • Direct and indirect
    • Black carbon emissions reductions could directly impact sea ice by reducing deposition of black carbon on sea ice, thereby preventing decreases in albedo.
    • Black carbon emissions reductions could indirectly impact sea ice by decreasing warming in the lower troposphere that occurs from the presence of black carbon.
• New or old ice?
  • Both
• Impact on sea ice
  • Unknown
    • No published studies found linking black carbon concentrations to sea ice extent or other sea ice parameters beyond albedo.

Scalability

• Likely scalable
  • Reductions in black carbon emissions of Arctic Council member states could have an outsized impact. Although these emission reductions comprise only about 5% of globally feasible reductions, deposition of black carbon in the Arctic would be reduced by 29.3 % (2030) and 33.8 % (2050), which corresponds to close to 60% of the achievable decrease in deposition of black carbon in the Arctic via global implementation of reductions (Kühn et al. 2020).

• Unknown

• < 10 years
  • Most mitigation strategies exist and could be deployed if appropriate policies were put in place (van Wijngaarden et al. 2023). The Clean Arctic Alliance offers a pathway over the next five years to regulate black carbon emissions from ships.

• Possible within 20 years
  • Once emissions reductions are implemented black carbon concentrations decrease rapidly (Bond et al. 2013, Kühn et al. 2020).

• Possible within 20 years
  • Once emissions reductions are implemented black carbon concentrations decrease rapidly (Bond et al. 2013, Kühn et al. 2020).

Cost

• $8-50 million per year
  • The estimated cost to achieve a 60% reduction in black carbon emissions reductions in Arctic shipping is $8-50 million per year (Corbett et al. 2010). These numbers are likely outdated due to changes in shipping regulations, so there is a need for updated cost estimates.

• Unknown, however, reducing black carbon emissions would reduce carbon footprint overall
  • Reductions in black carbon of 60% for Arctic shipping would avoid 9-70 million metric tons CO₂ eq per year (Corbett et al. 2010).

Impact on

• Uncertain, estimates range from 0-0.025
  • Current impact of black carbon emissions on sea ice albedo is albedo reduction of 0-0.004 (AMAP 2021 full report). Reductions in albedo on snow in the Arctic range from 0-0.025 (Bond et al. 2013).

• Global
  • Increase of 0.05°C – decrease of 0.02°C
    • Simulations of global black carbon emissions reductions produce a range of outcomes for global mean temperatures from warming of 0.05°C to cooling of 0.02°C by 2030 (Harmsen et al. 2020). There are large uncertainties in the impact of global reductions of black carbon due to cloud-aerosol interactions, and the impacts are difficult to assess (van Wijngaarden et al. 2023).
• Arctic region
  • Decreases up to 0.258°C by 2050
    • Black carbon emissions reductions could lead to temperature reductions in the Arctic of 0.141°C by 2030, 0.258°C by 2050 compared to 2015 (AMAP 2021 full report).

• Global
  • Decreases in direct shortwave radiative forcing up to 0.57 W/m² for 2050; impacts on effective (total) radiative forcing uncertain
    • Maximum reduction in black carbon emissions would lead to decreases in direct shortwave radiative forcing of 0.45 W/m² for 2030 and 0.57 W/m² for 2050 compared to 2010 (Kühn et al. 2020). However, predictions of decreases in total radiative forcing are variable due to cloud-aerosol interactions; the direct radiative effects due to black carbon emission reductions can be counteracted by cloud effects (Kühn et al. 2020).
    • In 2015, global radiative forcing from black carbon was 0.40 ±13 W/m² (AMAP 2021 full report)
• Arctic region
  • Decreases in direct shortwave radiative forcing up to 0.4 W/m²; impacts on effective (total) radiative forcing uncertain
    • Maximum reductions in direct radiative forcing in the Arctic of 0.4 W/m² possible in Arctic with global emissions reduction of black carbon (Kühn et al. 2020). Effective radiative forcing in the Arctic is highly variable due to variability in cloud cover and uncertainties due to cloud cover, surface albedo, aerosol burdens, cloud droplet number concentration, and heat transport (Kühn et al. 2020).
    • The current impact of black carbon emissions on instantaneous radiative forcing of Arctic sea ice is 0.5 W/m² (AMAP 2021 full report).

• Direct or indirect impact on sea ice?
  • Direct and indirect
    • Black carbon emissions reductions could directly impact sea ice by reducing deposition of black carbon on sea ice, thereby preventing decreases in albedo.
    • Black carbon emissions reductions could indirectly impact sea ice by decreasing warming in the lower troposphere that occurs from the presence of black carbon.
• New or old ice?
  • Both
• Impact on sea ice
  • Unknown
    • No published studies found linking black carbon concentrations to sea ice extent or other sea ice parameters beyond albedo.

Scalability

• Likely scalable
  • Reductions in black carbon emissions of Arctic Council member states could have an outsized impact. Although these emission reductions comprise only about 5% of globally feasible reductions, deposition of black carbon in the Arctic would be reduced by 29.3 % (2030) and 33.8 % (2050), which corresponds to close to 60% of the achievable decrease in deposition of black carbon in the Arctic via global implementation of reductions (Kühn et al. 2020).

• Unknown

• < 10 years
  • Most mitigation strategies exist and could be deployed if appropriate policies were put in place (van Wijngaarden et al. 2023). The Clean Arctic Alliance offers a pathway over the next five years to regulate black carbon emissions from ships.

• Possible within 20 years
  • Once emissions reductions are implemented black carbon concentrations decrease rapidly (Bond et al. 2013, Kühn et al. 2020)

• Possible within 20 years
  • Once emissions reductions are implemented black carbon concentrations decrease rapidly (Bond et al. 2013, Kühn et al. 2020)

Cost

• $8-50 million per year
  • The estimated cost to achieve a 60% reduction in black carbon emissions reductions in Arctic shipping is $8-50 million per year (Corbett et al. 2010). These numbers are likely outdated due to changes in shipping regulations, so there is a need for updated cost estimates.

• Unknown, however, reducing black carbon emissions would reduce carbon footprint overall
  • Reductions in black carbon of 60% for Arctic shipping would avoid 9-70 million metric tons CO₂ eq per year (Corbett et al. 2010).

• 8-9 – commercially available solutions exist, some testing of effectiveness still needed
• Summary of existing literature and studies:
  • 79% of 34 proposed technical and operational solutions in Zhang et al. (2019) are commercially available for shipping or are commercially available in other sectors.
  • Simulations show that declines in global anthropogenic black carbon emissions from 1990-2015 provided a cooling impact in the Arctic of -0.053°C per decade, demonstrating the potential for black carbon emissions reduction (AMAP 2021).
  • Most of the short list options for black carbon reduction by the IMO are commercially available and could be implemented within 5 years (IMO 2015).

• Technically feasible within 10 years
  • The Clean Arctic Alliance offers a pathway over the next five years to regulate black carbon emissions from ships.

• TRL: 8-9 – commercially available solutions exist, some testing of effectiveness still needed
• Summary of existing literature and studies:
  • 79% of 34 proposed technical and operational solutions in Zhang et al. (2019) are commercially available for shipping or are commercially available in other sectors.
  • Simulations show that declines in global anthropogenic black carbon emissions from 1990-2015 provided a cooling impact in the Arctic of -0.053°C per decade, demonstrating the potential for black carbon emissions reduction (AMAP 2021).
  • Most of the short list options for black carbon reduction by the IMO are commercially available and could be implemented within 5 years (IMO 2015).

• Technically feasible within 10 years
  • The Clean Arctic Alliance offers a pathway over the next five years to regulate black carbon emissions from ships.

• • TRL: 8-9 – commercially available solutions exist, some testing of effectiveness still needed
  • Summary of existing literature and studies:
    • 79% of 34 proposed technical and operational solutions in Zhang et al. (2019) are commercially available for shipping or are commercially available in other sectors.
    • Simulations show that declines in global anthropogenic black carbon emissions from 1990-2015 provided a cooling impact in the Arctic of -0.053°C per decade, demonstrating the potential for black carbon emissions reduction (AMAP 2021).
    • Most of the short list options for black carbon reduction by the IMO are commercially available and could be implemented within 5 years (IMO 2015).

• • Technically feasible within 10 years
    • The Clean Arctic Alliance offers a pathway over the next five years to regulate black carbon emissions from ships.

• TRL
  • TRL: 8-9 – commercially available solutions exist, some testing of effectiveness still needed
  • Summary of existing literature and studies:
    • 79% of 34 proposed technical and operational solutions in Zhang et al. (2019) are commercially available for shipping or are commercially available in other sectors.
    • Simulations show that declines in global anthropogenic black carbon emissions from 1990-2015 provided a cooling impact in the Arctic of -0.053°C per decade, demonstrating the potential for black carbon emissions reduction (AMAP 2021).
    • Most of the short list options for black carbon reduction by the IMO are commercially available and could be implemented within 5 years (IMO 2015).
• Technical feasibility within 10 years
  • Technically feasible within 10 years
    • The Clean Arctic Alliance offers a pathway over the next five years to regulate black carbon emissions from ships.

Physical and chemical changes

• Co-benefits
  • Reductions in black carbon would improve air quality (Organisation for Economic Co-operation and Development 2021).
• Risks
  • Black carbon reduction would also reduce other aerosols and may result in a net warming effect (van Wijngaarden et al. 2023).

Impacts on species

• Co-benefits
  • Reductions in black carbon would improve air quality (Organisation for Economic Co-operation and Development 2021), which could benefit wildlife dependent on sea ice.
• Risks
  • Unknown

Impacts on ecosystem

• Co-benefits
  • Reductions in black carbon would improve air quality (Organisation for Economic Co-operation and Development 2021), which could benefit sea ice ecosystems.
• Risks
  • Unknown

Impacts on society

• Co-benefits
  • Reductions in black carbon would improve air quality (Organisation for Economic Co-operation and Development 2021).
  • Reductions in black carbon would avoid 40% of air-pollution related deaths in Arctic Council countries by 2050 (Organisation for Economic Co-operation and Development 2021).
  • Reductions in global premature deaths due to particulate matter (Harmsen et al. 2020, Kühn et al. 2020).
• Risks
  • Unknown

Ease of reversibility

• Easy
  • See (van Wijngaarden et al. 2023)

Risk of termination shock

• No risk
  • See (van Wijngaarden et al. 2023)

Physical and chemical changes

• Co-benefits
  • Reductions in black carbon would improve air quality (Organisation for Economic Co-operation and Development 2021).
• Risks
  • Black carbon reduction would also reduce other aerosols and may result in a net warming effect (van Wijngaarden et al. 2023).

Impacts on species

• Co-benefits
  • Reductions in black carbon would improve air quality (Organisation for Economic Co-operation and Development 2021), which could benefit wildlife dependent on sea ice.
• Risks
  • Unknown

Impacts on ecosystem

• Co-benefits
  • Reductions in black carbon would improve air quality (Organisation for Economic Co-operation and Development 2021), which could benefit sea ice ecosystems.
• Risks
  • Unknown

Impacts on society

• Co-benefits
  • Reductions in black carbon would improve air quality (Organisation for Economic Co-operation and Development 2021).
  • Reductions in black carbon would avoid 40% of air-pollution related deaths in Arctic Council countries by 2050 (Organisation for Economic Co-operation and Development 2021).
  • Reductions in global premature deaths due to particulate matter (Harmsen et al. 2020, Kühn et al. 2020).
• Risks
  • Unknown

Ease of reversibility

• Impacts would be easy to reverse (van Wijngaarden et al. 2023).

Risk of termination shock

• This technique does not have a large risk of termination shock (van Wijngaarden et al. 2023).

• Co-benefits
  • Reductions in black carbon would improve air quality (Organisation for Economic Co-operation and Development 2021).
• Risks
  • Black carbon reduction would also reduce other aerosols and may result in a net warming effect (van Wijngaarden et al. 2023).

• Co-benefits
  • Reductions in black carbon would improve air quality (Organisation for Economic Co-operation and Development 2021), which could benefit wildlife dependent on sea ice.
• Risks
  • Unknown

• Co-benefits
  • Reductions in black carbon would improve air quality (Organisation for Economic Co-operation and Development 2021), which could benefit sea ice ecosystems.
• Risks
  • Unknown

• Co-benefits
  • Reductions in black carbon would improve air quality (Organisation for Economic Co-operation and Development 2021).
  • Reductions in black carbon would avoid 40% of air-pollution related deaths in Arctic Council countries by 2050 (Organisation for Economic Co-operation and Development 2021).
  • Reductions in global premature deaths due to particulate matter (Harmsen et al. 2020, Kühn et al. 2020).
• Risks
  • Unknown

• Impacts would be easy to reverse (van Wijngaarden et al. 2023).

• This technique does not have a large risk of termination shock (van Wijngaarden et al. 2023).

• Co-benefits
  • Reductions in black carbon would improve air quality (Organisation for Economic Co-operation and Development 2021)
• Risks
  • Black carbon reduction would also reduce other aerosols and may result in a net warming effect (van Wijngaarden et al. 2023).

• Co-benefits
  • Reductions in black carbon would improve air quality (Organisation for Economic Co-operation and Development 2021), which could benefit wildlife dependent on sea ice
• Risks
  • Unknown

• Co-benefits
  • Reductions in black carbon would improve air quality (Organisation for Economic Co-operation and Development 2021), which could benefit sea ice ecosystems
• Risks
  • Unknown

• Co-benefits
  • Reductions in black carbon would improve air quality (Organisation for Economic Co-operation and Development 2021)
  • Reductions in black carbon would avoid 40% of air-pollution related deaths in Arctic Council countries by 2050 (Organisation for Economic Co-operation and Development 2021)
  • Reductions in global premature deaths due to particulate matter (Harmsen et al. 2020, Kühn et al. 2020).
• Risks
  • Unknown

• Impacts would be easy to reverse (van Wijngaarden et al. 2023)

• This technique does not have a large risk of termination shock (van Wijngaarden et al. 2023)

• Both

• Typically addressed under national or regional air pollution laws (Zaelke et al. 2023).
• Voluntary programs of the Climate and Clean Air Coalition (CCAC) (Zaelke et al. 2023).
• International Maritime Organization (IMO) is the primary body responsible for regulating international shipping and has ongoing work to reduce black carbon emissions (IMO 2015).
  • Voluntary resolution by IMO to reduce black carbon emissions in the Arctic (IMO 2021, Zaelke et al. 2023).
  • Heavy fuel oil (HFO) ban by the IMO began in July 2024, which would have black carbon reductions as a side effect. However, there are waivers and exemptions for some ships until 2029, decreasing and delaying the effectiveness of the ban (Zaelke et al. 2023). Russia does not plan to implement the ban until 2029 (Bennett 2024).
• Arctic Council countries set a non-binding target of reducing black carbon emissions by 25-33% from 2013 levels by 2025 (Arctic Council 2019).
• There are no legally binding mitigation measures for BC except for commitments for BC reductions as fine particulate matter (PM2.5) under the Gothenburg Protocol to the Convention on Long-Range Transboundary Air Pollution (Gothenburg Protocol 1999, Kühn et al. 2020).
• The Clean Arctic Alliance is an organization with 23 not-for-profit organizational members dedicated to advancing significant reductions in black carbon emissions.

• 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
  • Unknown
• Procedural justice
  • Unknown
• Restorative justice
  • Unknown

• Groups supporting policy change and research, such as the Clean Arctic Alliance and the Climate and Clean Air Coalition, have been engaged in public outreach
• Raising awareness, sharing knowledge, and conducting outreach are part of the ABC-iCAP (Arctic Black Carbon impacting on Climate and Air Pollution) project, funded by the European Union and managed by AMAP (Arctic Monitoring and Assessment Programme).

• The Arctic Council addresses black carbon through multiple working groups that include Indigenous representation with specific projects focused on Indigenous communities.
• The Inuit Circumpolar Council has co-sponsored submissions to the International Maritime Organization (IMO) and is seeking full consultative status with the IMO.

• Both

• Typically addressed under national or regional air pollution laws (Zaelke et al. 2023)
• Voluntary programs of the Climate and Clean Air Coalition (CCAC) (Zaelke et al. 2023).
• International Maritime Organization (IMO) is the primary body responsible for regulating international shipping and has ongoing work to reduce black carbon emissions (IMO 2015).
  • Voluntary resolution by IMO to reduce black carbon emissions in the Arctic (IMO 2021, Zaelke et al. 2023)
  • Heavy fuel oil (HFO) ban by the IMO began in July 2024, which would have black carbon reductions as a side effect. However, there are waivers and exemptions for some ships until 2029, decreasing and delaying the effectiveness of the ban (Zaelke et al. 2023). Russia does not plan to implement the ban until 2029 (Bennett 2024).
• Arctic Council countries set a non-binding target of reducing black carbon emissions by 25-33% from 2013 levels by 2025 (Arctic Council 2019).
• There are no legally binding mitigation measures for BC except for commitments for BC reductions as fine particulate matter (PM2.5) under the Gothenburg Protocol to the Convention on Long-Range Transboundary Air Pollution (Gothenburg Protocol 1999, Kühn et al. 2020).
• The Clean Arctic Alliance is an organization with 23 not-for-profit organizational members dedicated to advancing significant reductions in black carbon emissions

• 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
  • Unknown
• Procedural justice
  • Unknown
• Restorative justice
  • Unknown

• Groups supporting policy change and research, such as the Clean Arctic Alliance and the Climate and Clean Air Coalition, have been engaged in public outreach
• Raising awareness, sharing knowledge, and conducting outreach are part of the ABC-iCAP (Arctic Black Carbon impacting on Climate and Air Pollution) project, funded by the European Union and managed by AMAP (Arctic Monitoring and Assessment Programme).

• The Arctic Council addresses black carbon through multiple working groups that include Indigenous representation with specific projects focused on Indigenous communities.
• The Inuit Circumpolar Council has co-sponsored submissions to the International Maritime Organization (IMO) and is seeking full consultative status with the IMO.

• Both

• Typically addressed under national or regional air pollution laws (Zaelke et al. 2023)
• Voluntary programs of the Climate and Clean Air Coalition (CCAC) (Zaelke et al. 2023).
• International Maritime Organization (IMO) is the primary body responsible for regulating international shipping and has ongoing work to reduce black carbon emissions (IMO 2015).
  • Voluntary resolution by IMO to reduce black carbon emissions in the Arctic (IMO 2021, Zaelke et al. 2023)
  • Heavy fuel oil (HFO) ban by the IMO began in July 2024, which would have black carbon reductions as a side effect. However, there are waivers and exemptions for some ships until 2029, decreasing and delaying the effectiveness of the ban (Zaelke et al. 2023). Russia does not plan to implement the ban until 2029 (Bennett 2024).
• Arctic Council countries set a non-binding target of reducing black carbon emissions by 25-33% from 2013 levels by 2025 (Arctic Council 2019).
• There are no legally binding mitigation measures for BC except for commitments for BC reductions as fine particulate matter (PM2.5) under the Gothenburg Protocol to the Convention on Long-Range Transboundary Air Pollution (Gothenburg Protocol 1999, Kühn et al. 2020).
• The Clean Arctic Alliance is an organization with 23 not-for-profit organizational members dedicated to advancing significant reductions in black carbon emissions

• 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
  • Unknown
• Procedural justice
  • Unknown
• Restorative justice
  • Unknown

• Groups supporting policy change and research, such as the Clean Arctic Alliance and the Climate and Clean Air Coalition, have been engaged in public outreach
• Raising awareness, sharing knowledge, and conducting outreach are part of the ABC-iCAP (Arctic Black Carbon impacting on Climate and Air Pollution) project, funded by the European Union and managed by AMAP (Arctic Monitoring and Assessment Programme).

• The Arctic Council addresses black carbon through multiple working groups that include Indigenous representation with specific projects focused on Indigenous communities.
• The Inuit Circumpolar Council has co-sponsored submissions to the International Maritime Organization (IMO) and is seeking full consultative status with the IMO.

• Both

• Typically addressed under national or regional air pollution laws (Zaelke et al. 2023)
• Voluntary programs of the Climate and Clean Air Coalition (CCAC) (Zaelke et al. 2023).
• International Maritime Organization (IMO) is the primary body responsible for regulating international shipping and has ongoing work to reduce black carbon emissions (IMO 2015).
  • Voluntary resolution by IMO to reduce black carbon emissions in the Arctic (IMO 2021, Zaelke et al. 2023)
  • Heavy fuel oil (HFO) ban by the IMO began in July 2024, which would have black carbon reductions as a side effect. However, there are waivers and exemptions for some ships until 2029, decreasing and delaying the effectiveness of the ban (Zaelke et al. 2023). Russia does not plan to implement the ban until 2029 (Bennett 2024).
• Arctic Council countries set a non-binding target of reducing black carbon emissions by 25-33% from 2013 levels by 2025 (Arctic Council 2019).
• There are no legally binding mitigation measures for BC except for commitments for BC reductions as fine particulate matter (PM2.5) under the Gothenburg Protocol to the Convention on Long-Range Transboundary Air Pollution (Gothenburg Protocol 1999, Kühn et al. 2020).
• The Clean Arctic Alliance is an organization with 23 not-for-profit organizational members dedicated to advancing significant reductions in black carbon emissions

• Distributive justice
  • Unknown
• Procedural justice
  • Unknown
• Restorative justice
  • Unknown

• Groups supporting policy change and research, such as the Clean Arctic Alliance and the Climate and Clean Air Coalition, have been engaged in public outreach
• Raising awareness, sharing knowledge, and conducting outreach are part of the ABC-iCAP (Arctic Black Carbon impacting on Climate and Air Pollution) project, funded by the European Union and managed by AMAP (Arctic Monitoring and Assessment Programme).

• The Arctic Council addresses black carbon through multiple working groups that include Indigenous representation with specific projects focused on Indigenous communities.
• The Inuit Circumpolar Council has co-sponsored submissions to the International Maritime Organization (IMO) and is seeking full consultative status with the IMO.