• In this strategy microbubbles or reflective foams would be applied to the water surface to increase reflectivity. Microbubbles could be achieved through available technologies (Crook et al. 2016), or other specialized methods to be developed (Seitz 2011). Application has been proposed via ship and within ship wakes (Crook et al. 2016). The lifetime of the microbubbles could be extended by using a natural or synthetic surfactant up to a few months (Seitz 2011, Aziz et al. 2014). This approach has been explored through laboratory experiments (e.g., feasibility of foam creation by Aziz et al. 2014) and models. Surface ocean albedo enhancement has been modeled specifically for the Arctic area (Cvijanovic et al. 2015, Mengis et al. 2016), for low latitude areas with higher amounts of solar radiation and sunlight (Seitz 2011, Gabriel et al. 2017), and for application via ship wakes utilizing existing shipping routes (Crook et al. 2016). These modeling studies apply a theoretical increase to albedo.

• Expected physical changes (global)
  • Increase surface albedo at application site, decrease heat absorption, which may lead to global decrease in atmospheric temperature, depending upon the spatial scale of application (Gabriel et al. 2017).
• Expected physical changes (Arctic region)
  • Increase surface albedo, decrease absorption in the ocean, lower heat exchange with the atmosphere, limit sea ice loss, lower ocean and atmospheric temperature (Mengis et al. 2016).

• Global deployment in low latitudes.
• Arctic deployment in ice free area in Arctic Ocean – maximum of 5,100,000 km² (Mengis et al. 2016).

• Surface of ocean

• Several scenarios have been modeled:
  • Global deployment focused in low latitudes in the Southern Hemisphere to create global temperature decrease and maintain or enhance precipitation patterns (Gabriel et al. 2017).
  • Deployments taking advantage of existing shipping routes (largely focused in the Northern Hemisphere; Crook et al. 2016).
  • Arctic Ocean deployment focused on sea ice restoration (Cvijanovic et al. 2015, Mengis et al. 2016).

• Whenever there is sunlight, limited to summer for Arctic-specific deployment.

• In this strategy microbubbles or reflective foams would be applied to the water surface to increase reflectivity. Microbubbles could be achieved through available technologies (Crook et al. 2016), or other specialized methods to be developed (Seitz 2011). Application has been proposed via ship and within ship wakes (Crook et al. 2016). The lifetime of the microbubbles could be extended by using a natural or synthetic surfactant up to a few months (Seitz 2011, Aziz et al. 2014). This approach has been explored through laboratory experiments (e.g., feasibility of foam creation by Aziz et al. 2014) and models. Surface ocean albedo enhancement has been modeled specifically for the Arctic area (Cvijanovic et al. 2015, Mengis et al. 2016), for low latitude areas with higher amounts of solar radiation and sunlight (Seitz 2011, Gabriel et al. 2017), and for application via ship wakes utilizing existing shipping routes (Crook et al. 2016). These modeling studies apply a theoretical increase to albedo.

• Expected physical changes (global)
  • Increase surface albedo at application site, decrease heat absorption, which may lead to global decrease in atmospheric temperature, depending upon the spatial scale of application (Gabriel et al. 2017).
• Expected physical changes (Arctic region)
  • Increase surface albedo, decrease absorption in the ocean, lower heat exchange with the atmosphere, limit sea ice loss, lower ocean and atmospheric temperature (Mengis et al. 2016).

• Global deployment in low latitudes.
• Arctic deployment in ice free area in Arctic Ocean – maximum of 5,100,000 km² (Mengis et al. 2016).

• Surface of ocean

• Several scenarios have been modeled:
  • Global deployment focused in low latitudes in the Southern Hemisphere to create global temperature decrease and maintain or enhance precipitation patterns (Gabriel et al. 2017).
  • Deployments taking advantage of existing shipping routes (largely focused in the Northern Hemisphere; Crook et al. 2016).
  • Arctic Ocean deployment focused on sea ice restoration (Cvijanovic et al. 2015, Mengis et al. 2016).

• Whenever there is sunlight, limited to summer for Arctic-specific deployment.

• In this strategy microbubbles or reflective foams would be applied to the water surface to increase reflectivity. Microbubbles could be achieved through available technologies (Crook et al. 2016), or other specialized methods to be developed (Seitz 2011). Application has been proposed via ship and within ship wakes (Crook et al. 2016). The lifetime of the microbubbles could be extended by using a natural or synthetic surfactant up to a few months (Seitz 2011, Aziz et al. 2014). This approach has been explored through laboratory experiments (e.g., feasibility of foam creation by Aziz et al. 2014) and models. Surface ocean albedo enhancement has been modeled specifically for the Arctic area (Cvijanovic et al. 2015, Mengis et al. 2016), for low latitude areas with higher amounts of solar radiation and sunlight (Seitz 2011, Gabriel et al. 2017), and for application via ship wakes utilizing existing shipping routes (Crook et al. 2016). These modeling studies apply a theoretical increase to albedo.

• Expected physical changes (global)
  • Increase surface albedo at application site, decrease heat absorption, which may lead to global decrease in atmospheric temperature, depending upon the spatial scale of application (Gabriel et al. 2017).
• Expected physical changes (Arctic region)
  • Increase surface albedo, decrease absorption in the ocean, lower heat exchange with the atmosphere, limit sea ice loss, lower ocean and atmospheric temperature (Mengis et al. 2016).

• Global deployment in low latitudes.
• Arctic deployment in ice free area in Arctic Ocean – maximum of 5,100,000 km² (Mengis et al. 2016).

• Surface of ocean

• Several scenarios have been modeled:
  • Global deployment focused in low latitudes in the Southern Hemisphere to create global temperature decrease and maintain or enhance precipitation patterns (Gabriel et al. 2017).
  • Deployments taking advantage of existing shipping routes (largely focused in the Northern Hemisphere; Crook et al. 2016).
  • Arctic Ocean deployment focused on sea ice restoration (Cvijanovic et al. 2015, Mengis et al. 2016).

• Whenever there is sunlight, limited to summer for Arctic-specific deployment.

• In this strategy microbubbles or reflective foams would be applied to the water surface to increase reflectivity. Microbubbles could be achieved through available technologies (Crook et al. 2016), or other specialized methods to be developed (Seitz 2011). Application has been proposed via ship and within ship wakes (Crook et al. 2016). The lifetime of the microbubbles could be extended by using a natural or synthetic surfactant up to a few months (Seitz 2011, Aziz et al. 2014). This approach has been explored through laboratory experiments (e.g., feasibility of foam creation by Aziz et al. 2014) and models. Surface ocean albedo enhancement has been modeled specifically for the Arctic area (Cvijanovic et al. 2015, Mengis et al. 2016), for low latitude areas with higher amounts of solar radiation and sunlight (Seitz 2011, Gabriel et al. 2017), and for application via ship wakes utilizing existing shipping routes (Crook et al. 2016). These modeling studies apply a theoretical increase to albedo.

• Expected physical changes (global)
  • Increase surface albedo at application site, decrease heat absorption, which may lead to global decrease in atmospheric temperature, depending upon the spatial scale of application (Gabriel et al. 2017).
• Expected physical changes (Arctic region)
  • Increase surface albedo, decrease absorption in the ocean, lower heat exchange with the atmosphere, limit sea ice loss, lower ocean and atmospheric temperature (Mengis et al. 2016).

• Global deployment in low latitudes
• Arctic deployment in ice free area in Arctic Ocean – maximum of 5,100,000 km² (Mengis et al. 2016)

• Surface of ocean

• Several scenarios have been modeled:
  • Global deployment focused in low latitudes in the Southern Hemisphere to create global temperature decrease and maintain or enhance precipitation patterns (Gabriel et al. 2017).
  • Deployments taking advantage of existing shipping routes (largely focused in the Northern Hemisphere; Crook et al. 2016).
  • Arctic Ocean deployment focused on sea ice restoration (Cvijanovic et al. 2015, Mengis et al. 2016).

• Whenever there is sunlight, limited to summer for Arctic-specific deployment

• In this strategy microbubbles or reflective foams would be applied to the water surface to increase reflectivity. Microbubbles could be achieved through available technologies (Crook et al. 2016), or other specialized methods to be developed (Seitz 2011). Application has been proposed via ship and within ship wakes (Crook et al. 2016). The lifetime of the microbubbles could be extended by using a natural or synthetic surfactant up to a few months (Seitz 2011, Aziz et al. 2014). This approach has been explored through laboratory experiments (e.g., feasibility of foam creation by Aziz et al. 2014) and models. Surface ocean albedo enhancement has been modeled specifically for the Arctic area (Cvijanovic et al. 2015, Mengis et al. 2016), for low latitude areas with higher amounts of solar radiation and sunlight (Seitz 2011, Gabriel et al. 2017), and for application via ship wakes utilizing existing shipping routes (Crook et al. 2016). These modeling studies apply a theoretical increase to albedo.

• Expected physical changes (global)
  • Increase surface albedo at application site, decrease heat absorption, which may lead to global decrease in atmospheric temperature, depending upon the spatial scale of application (Gabriel et al. 2017).
• Expected physical changes (Arctic region)
  • Increase surface albedo, decrease absorption in the ocean, lower heat exchange with the atmosphere, limit sea ice loss, lower ocean and atmospheric temperature (Mengis et al. 2016).

• Global deployment in low latitudes
• Arctic deployment in ice free area in Arctic Ocean – maximum of 5,100,000 km² (Mengis et al. 2016)

• Surface of ocean

• Several scenarios have been modeled:
  • Global deployment focused in low latitudes in the Southern Hemisphere to create global temperature decrease and maintain or enhance precipitation patterns (Gabriel et al. 2017).
  • Deployments taking advantage of existing shipping routes (largely focused in the Northern Hemisphere; Crook et al. 2016).
  • Arctic Ocean deployment focused on sea ice restoration (Cvijanovic et al. 2015, Mengis et al. 2016).

• Whenever there is sunlight, limited to summer for Arctic-specific deployment

• In this strategy microbubbles or reflective foams would be applied to the water surface to increase reflectivity. Microbubbles could be achieved through available technologies (Crook et al. 2016), or other specialized methods to be developed (Seitz 2011). Application has been proposed via ship and within ship wakes (Crook et al. 2016). The lifetime of the microbubbles could be extended by using a natural or synthetic surfactant up to a few months (Seitz 2011, Aziz et al. 2014). This approach has been explored through laboratory experiments (e.g., feasibility of foam creation by Aziz et al. 2014) and models. Surface ocean albedo enhancement has been modeled specifically for the Arctic area (Cvijanovic et al. 2015, Mengis et al. 2016), for low latitude areas with higher amounts of solar radiation and sunlight (Seitz 2011, Gabriel et al. 2017), and for application via ship wakes utilizing existing shipping routes (Crook et al. 2016). These modeling studies apply a theoretical increase to albedo.

• Expected physical changes (global)
  • Increase surface albedo at application site, decrease heat absorption, which may lead to global decrease in atmospheric temperature, depending upon the spatial scale of application (Gabriel et al. 2017)
• Expected physical changes (Arctic region)
  • Increase surface albedo, decrease absorption in the ocean, lower heat exchange with the atmosphere, limit sea ice loss, lower ocean and atmospheric temperature (Mengis et al. 2016).

• Global deployment in low latitudes
• Arctic deployment in ice free area in Arctic Ocean – maximum of 5,100,000 km² (Mengis et al. 2016)

• Surface of ocean

• Several scenarios have been modeled:
  • Global deployment focused in low latitudes in the Southern Hemisphere to create global temperature decrease and maintain or enhance precipitation patterns (Gabriel et al. 2017).
  • Deployments taking advantage of existing shipping routes (largely focused in the Northern Hemisphere; Crook et al. 2016).
  • Arctic Ocean deployment focused on sea ice restoration (Cvijanovic et al. 2015, Mengis et al. 2016).

• Whenever there is sunlight, limited to summer for Arctic-specific deployment

• In this strategy microbubbles or reflective foams would be applied to the water surface to increase reflectivity. Microbubbles could be achieved through available technologies (Crook et al. 2016), or other specialized methods to be developed (Seitz 2011). Application has been proposed via ship and within ship wakes (Crook et al. 2016). The lifetime of the microbubbles could be extended by using a natural or synthetic surfactant up to a few months (Seitz 2011, Aziz et al. 2014). This approach has been explored through laboratory experiments (e.g., feasibility of foam creation by Aziz et al. 2014) and models. Surface ocean albedo enhancement has been modeled specifically for the Arctic area (Cvijanovic et al. 2015, Mengis et al. 2016), for low latitude areas with higher amounts of solar radiation and sunlight (Seitz 2011, Gabriel et al. 2017), and for application via ship wakes utilizing existing shipping routes (Crook et al. 2016). These modeling studies apply a theoretical increase to albedo.

• Expected physical changes (global)
  • Increase surface albedo at application site, decrease heat absorption, which may lead to global decrease in atmospheric temperature, depending upon the spatial scale of application (Gabriel et al. 2017)
• Expected physical changes (Arctic region)
  • Increase surface albedo, decrease absorption in the ocean, lower heat exchange with the atmosphere, limit sea ice loss, lower ocean and atmospheric temperature (Mengis et al. 2016).

• Global deployment in low latitudes
• Arctic deployment in ice free area in Arctic Ocean – maximum of 5,100,000 km² (Mengis et al. 2016)

• Surface of ocean

• Several scenarios have been modeled:
  • Global deployment focused in low latitudes in the Southern Hemisphere to create global temperature decrease and maintain or enhance precipitation patterns (Gabriel et al. 2017).
  • Deployments taking advantage of existing shipping routes (largely focused in the Northern Hemisphere; Crook et al. 2016).
  • Arctic Ocean deployment focused on sea ice restoration (Cvijanovic et al. 2015, Mengis et al. 2016).

• Whenever there is sunlight, limited to summer for Arctic-specific deployment

• In this strategy microbubbles or reflective foams would be applied to the water surface to increase reflectivity. Microbubbles could be achieved through available technologies (Crook et al. 2016), or other specialized methods to be developed (Seitz 2011). Application has been proposed via ship and within ship wakes (Crook et al. 2016). The lifetime of the microbubbles could be extended by using a natural or synthetic surfactant up to a few months (Seitz 2011, Aziz et al. 2014). This approach has been explored through laboratory experiments (e.g., feasibility of foam creation by Aziz et al. 2014) and models. Surface ocean albedo enhancement has been modeled specifically for the Arctic area (Cvijanovic et al. 2015, Mengis et al. 2016), for low latitude areas with higher amounts of solar radiation and sunlight (Seitz 2011, Gabriel et al. 2017), and for application via ship wakes utilizing existing shipping routes (Crook et al. 2016). These modeling studies apply a theoretical increase to albedo.

• Expected physical changes (global)
  • Increase surface albedo at application site, decrease heat absorption, which may lead to global decrease in atmospheric temperature, depending upon the spatial scale of application (Gabriel et al. 2017)
• Expected physical changes (Arctic region)
  • Increase surface albedo, decrease absorption in the ocean, lower heat exchange with the atmosphere, limit sea ice loss, lower ocean and atmospheric temperature (Mengis et al. 2016).

• Global deployment in low latitudes
• Arctic deployment in ice free area in Arctic Ocean – maximum of 5,100,000 km2 (Mengis et al. 2016)

• Surface of ocean

• Several scenarios have been modeled:
  • Global deployment focused in low latitudes in the Southern Hemisphere to create global temperature decrease and maintain or enhance precipitation patterns (Gabriel et al. 2017).
  • Deployments taking advantage of existing shipping routes (largely focused in the Northern Hemisphere; Crook et al. 2016).
  • Arctic Ocean deployment focused on sea ice restoration (Cvijanovic et al. 2015, Mengis et al. 2016).

• Whenever there is sunlight, limited to summer for Arctic-specific deployment

Impact on

• Global low latitude studies increased from 0.05-0.1 to 0.15 (Gabriel et al. 2017); Arctic studies increased from 0.3-0.4 to 0.8 (Mengis et al. 2016).
  • Modeling study looked at increasing albedo to 0.15 over three subtropical ocean gyres in Southern Hemisphere (could not find estimate of total foamed area; Gabriel et al. 2017). Calm seas have albedo 0.05-0.1, bubbles of ocean whitecaps albedo 0.22 (Moore et al. 2000 cited in Seitz 2011).
  • Modeling study of Arctic Ocean looked at surface albedo of 0.8, model’s default value for sea ice, whenever sea ice concentration dropped below 50% in Arctic grid cells (Mengis et al. 2016). Additional study in the Arctic region adjusted ocean albedo to 0.7-0.9 across simulations (Cvjanovic et al. 2015).

• Global
  • Estimates of global average surface temperature decreases from 0.0-2.7°C, dependent on the area of deployment (Seitz 2011, Cvijanovic et al. 2015, Crook et al. 2016, Mengis et al. 2016, Gabriel et al. 2017). Arctic specific deployments have little potential to decrease global temperature (Cvijanovic et al. 2015, Mengis et al. 2016).
    • Model of global deployment over all seawater increasing albedo by 0.05 yielded estimate of a decrease in temperature of 7°C (Seitz 2011). Some areas saw cooling over 5°C.
    • A later model focused on deployment in subtropical gyres in the Southern Hemisphere with albedo set to 0.15 gave global mean surface temperature decrease of 0.53°C over 2030-2069 (Gabriel et al. 2017).
    • Increasing albedo by 0.2 in ship wakes of existing shipping lanes in model yields 0.5°C reduction in global mean temperature (Crook et al. 2016).
    • Targeted modeling studies of deployment in the Arctic Ocean estimated no change or a slight reduction in global mean temperature (Cvijanovic et al. 2015, Mengis et al. 2016).
• Arctic region
  • Modeling studies with targeted Arctic Ocean deployments report temperature decreases in the Arctic of 1.2-2°C (Cvijanovic et al. 2015, Mengis et al. 2016). Deployment in the Southern Hemisphere decreased temperatures in the Arctic by 0-1°C (Gabriel et al. 2017).

• Global
  • Decreased radiative forcing of 0.9-1.5 W/m² (Crook et al. 2016, Gabriel et al. 2017)
    • Increasing albedo of ship wakes in existing shipping lanes decreased radiative forcing by 0.9 ± 6 W/m² globally and 1.8 ± 0.9 W/m² in the Northern Hemisphere; if wake lifetime were increased to 3 months, reduction could reach 3 W/m² (Crook et al. 2016).
    • Model of albedo set to 0.15 in subtropical gyres in the Southern Hemisphere gave global decrease in radiative forcing of 1.5 W/m².
• Arctic region
  • Reductions in solar energy absorption by 65-82 W/m² in summer (Mengis et al. 2016).
    • Modeling study of Arctic Ocean reports decreases in radiative forcing with albedo modification of 65 W/m² for RCP4.5 and 82 W/m² for RCP8.5.

• Direct or indirect impact on sea ice?
  • Indirect impact on sea ice via reductions in radiative forcing and temperature.
• New or old ice?
  • Temperature reductions could enhance production of new ice and prevent melting of existing ice.
• Impact on sea ice
  • Increase in sea ice extent 40-53% and delayed summer sea ice decline by 25-60 yr
    • Modeling study of surface albedo alteration by Cvijanovic et al. 2015 in Arctic showed that sea ice extent will stabilize at 40% of preindustrial value, compared to 3% without albedo modifications.
    • Modeling study of ocean albedo modification by Mengis et al. 2016 delays Arctic sea ice decline by 25-60 years depending on emissions scenario. 53% of summer sea ice area is maintained with ocean albedo modification compared to 27% without ocean albedo modification (compared to 2005-2015). Ice thickness increases as well with ocean albedo modification in these simulations.

Scalability

• Unknown
  • Could be scalable first with implementation on ships (e.g., Crook et al. 2016), but that relies on developing appropriate infrastructure. This field could benefit from technologies developed to reduce drag of ships.

• Unknown
  • Microbubble concentrates of approximately 80,000–100,000 ppmv produced by commercial hydrosol generators have the potential to double the albedo even when diluted by a factor of 10³–10⁴ (Seitz 2011).
  • Reflective foams tested by Aziz et al. 2014 had lifetimes of 3 months without wave action.

• Unknown, will require:
  • Development of a non-toxic, inert surfactant with no impact on living organisms that increases ocean albedo.
  • Development of deployment device.

• • Unknown

• • Unknown

Cost

• Unknown
  • Estimated cost of surfactants to stabilize microbubbles is <$10/kg, or <$100 km⁻¹ (Seitz 2011).
  • Additional costs would be incurred in deployment, likely by ships.

• Unknown
  • A study by Ortega and Evans (2019) looked at energy required to maintain foams in the open ocean and proposed using energy derived from wave, wind, solar, or ship lubrication compressor power. They also suggested matching surfactant additions with infrastructure on ships.

Impact on

• Global low latitude studies increased from 0.05-0.1 to 0.15 (Gabriel et al. 2017); Arctic studies increased from 0.3-0.4 to 0.8 (Mengis et al. 2016).
  • Modeling study looked at increasing albedo to 0.15 over three subtropical ocean gyres in Southern Hemisphere (could not find estimate of total foamed area; Gabriel et al. 2017). Calm seas have albedo 0.05-0.1, bubbles of ocean whitecaps albedo 0.22 (Moore et al. 2000 cited in Seitz 2011).
  • Modeling study of Arctic Ocean looked at surface albedo of 0.8, model’s default value for sea ice, whenever sea ice concentration dropped below 50% in Arctic grid cells (Mengis et al. 2016). Additional study in the Arctic region adjusted ocean albedo to 0.7-0.9 across simulations (Cvjanovic et al. 2015).

• Global
  • Estimates of global average surface temperature decreases from 0.0-2.7°C, dependent on the area of deployment (Seitz 2011, Cvijanovic et al. 2015, Crook et al. 2016, Mengis et al. 2016, Gabriel et al. 2017). Arctic specific deployments have little potential to decrease global temperature (Cvijanovic et al. 2015, Mengis et al. 2016).
    • Model of global deployment over all seawater increasing albedo by 0.05 yielded estimate of a decrease in temperature of 7°C (Seitz 2011). Some areas saw cooling over 5°C.
    • A later model focused on deployment in subtropical gyres in the Southern Hemisphere with albedo set to 0.15 gave global mean surface temperature decrease of 0.53°C over 2030-2069 (Gabriel et al. 2017).
    • Increasing albedo by 0.2 in ship wakes of existing shipping lanes in model yields 0.5°C reduction in global mean temperature (Crook et al. 2016).
    • Targeted modeling studies of deployment in the Arctic Ocean estimated no change or a slight reduction in global mean temperature (Cvijanovic et al. 2015, Mengis et al. 2016).
• Arctic region
  • Modeling studies with targeted Arctic Ocean deployments report temperature decreases in the Arctic of 1.2-2°C (Cvijanovic et al. 2015, Mengis et al. 2016). Deployment in the Southern Hemisphere decreased temperatures in the Arctic by 0-1 °C (Gabriel et al. 2017).

• Global
  • Decreased radiative forcing of 0.9 – 1.5 W/m² (Crook et al. 2016, Gabriel et al. 2017)
    • Increasing albedo of ship wakes in existing shipping lanes decreased radiative forcing by 0.9 ± 6 W/m² globally and 1.8 ± 0.9 W/m² in the Northern Hemisphere; if wake lifetime were increased to 3 months, reduction could reach 3 W/m² (Crook et al. 2016).
    • Model of albedo set to 0.15 in subtropical gyres in the Southern Hemisphere gave global decrease in radiative forcing of 1.5 W/m².
• Arctic region
  • Reductions in solar energy absorption by 65-82 W/m² in summer (Mengis et al. 2016).
    • Modeling study of Arctic Ocean reports decreases in radiative forcing with albedo modification of 65 W/m² for RCP4.5 and 82 W/m² for RCP 8.5.

• Direct or indirect impact on sea ice?
  • Indirect impact on sea ice via reductions in radiative forcing and temperature.
• New or old ice?
  • Temperature reductions could enhance production of new ice and prevent melting of existing ice.
• Impact on sea ice
  • Increase in sea ice extent 40-53% and delayed summer sea ice decline by 25-60 yr
    • Modeling study of surface albedo alteration by Cvijanovic et al. 2015 in Arctic showed that sea ice extent will stabilize at 40% of preindustrial value, compared to 3% without albedo modifications.
    • Modeling study of ocean albedo modification by Mengis et al. 2016 delays Arctic sea ice decline by 25-60 years depending on emissions scenario. 53% of summer sea ice area is maintained with ocean albedo modification compared to 27% without ocean albedo modification (compared to 2005-2015). Ice thickness increases as well with ocean albedo modification in these simulations.

Scalability

• Unknown
  • Could be scalable first with implementation on ships (e.g., Crook et al. 2016), but that relies on developing appropriate infrastructure. This field could benefit from technologies developed to reduce drag of ships.

• Unknown
  • Microbubble concentrates of ∼80,000–100,000 ppmv produced by commercial hydrosol generators have the potential to double the albedo even when diluted by a factor of 10³–10⁴ (Seitz 2011).
  • Reflective foams tested by Aziz et al. 2014 had lifetimes of 3 months without wave action.

• Unknown, will require:
  • Development of a non-toxic, inert surfactant with no impact on living organisms that increases ocean albedo.
  • Development of deployment device.

• • Unknown

• • Unknown

Cost

• Unknown
  • Estimated cost of surfactants to stabilize microbubbles is <$10/kg, or <$100 km⁻¹ (Seitz 2011).
  • Additional costs would be incurred in deployment, likely by ships.

• Unknown
  • A study by Ortega and Evans (2019) looked at energy required to maintain foams in the open ocean and proposed using energy derived from wave, wind, solar, or ship lubrication compressor power. They also suggested matching surfactant additions with infrastructure on ships.

Impact on

• Global low latitude studies increased from 0.05-0.1 to 0.15 (Gabriel et al. 2017); Arctic studies increased from 0.3-0.4 to 0.8 (Mengis et al. 2016)
  • Modeling study looked at increasing albedo to 0.15 over three subtropical ocean gyres in Southern Hemisphere (could not find estimate of total foamed area; Gabriel et al. 2017). Calm seas have albedo 0.05-0.1, bubbles of ocean whitecaps albedo 0.22 (Moore et al. 2000 cited in Seitz 2011).
  • Modeling study of Arctic Ocean looked at surface albedo of 0.8, model’s default value for sea ice, whenever sea ice concentration dropped below 50% in Arctic grid cells (Mengis et al. 2016). Additional study in the Arctic region adjusted ocean albedo to 0.7-0.9 across simulations (Cvjanovic et al. 2015).

• Global
  • Estimates of global average surface temperature decreases from 0.0-2.7°C, dependent on the area of deployment (Seitz 2011, Cvijanovic et al. 2015, Crook et al. 2016, Mengis et al. 2016, Gabriel et al. 2017). Arctic specific deployments have little potential to decrease global temperature (Cvijanovic et al. 2015, Mengis et al. 2016).
    • Model of global deployment over all seawater increasing albedo by 0.05 yielded estimate of a decrease in temperature of 7°C (Seitz 2011). Some areas saw cooling over 5°C.
    • A later model focused on deployment in subtropical gyres in the Southern Hemisphere with albedo set to 0.15 gave global mean surface temperature decrease of 0.53°C over 2030-2069 (Gabriel et al. 2017).
    • Increasing albedo by 0.2 in ship wakes of existing shipping lanes in model yields 0.5°C reduction in global mean temperature (Crook et al. 2016).
    • Targeted modeling studies of deployment in the Arctic Ocean estimated no change or a slight reduction in global mean temperature (Cvijanovic et al. 2015, Mengis et al. 2016).
• Arctic region
  • Modeling studies with targeted Arctic Ocean deployments report temperature decreases in the Arctic of 1.2-2°C (Cvijanovic et al. 2015, Mengis et al. 2016). Deployment in the Southern Hemisphere decreased temperatures in the Arctic by 0-1 °C (Gabriel et al. 2017).

• Global
  • Decreased radiative forcing of 0.9 – 1.5 W/m² (Crook et al. 2016, Gabriel et al. 2017)
    • Increasing albedo of ship wakes in existing shipping lanes decreased radiative forcing by 0.9 ± 6 W/m² globally and 1.8 ± 0.9 W/m² in the Northern Hemisphere; if wake lifetime were increased to 3 months, reduction could reach 3 W/m² (Crook et al. 2016).
    • Model of albedo set to 0.15 in subtropical gyres in the Southern Hemisphere gave global decrease in radiative forcing of 1.5 W/m².
• Arctic region
  • Reductions in solar energy absorption by 65-82 W/m² in summer (Mengis et al. 2016).
    • Modeling study of Arctic Ocean reports decreases in radiative forcing with albedo modification of 65 W/m² for RCP4.5 and 82 W/m² for RCP 8.5.

• Direct or indirect impact on sea ice?
  • Indirect impact on sea ice via reductions in radiative forcing and temperature
• New or old ice?
  • Temperature reductions could enhance production of new ice and prevent melting of existing ice
• Impact on sea ice
  • Increase in sea ice extent 40-53% and delayed summer sea ice decline by 25-60 yr
    • Modeling study of surface albedo alteration by Cvijanovic et al. 2015 in Arctic showed that sea ice extent will stabilize at 40% of preindustrial value, compared to 3% without albedo modifications.
    • Modeling study of ocean albedo modification by Mengis et al. 2016 delays Arctic sea ice decline by 25-60 years depending on emissions scenario. 53% of summer sea ice area is maintained with ocean albedo modification compared to 27% without ocean albedo modification (compared to 2005-2015). Ice thickness increases as well with ocean albedo modification in these simulations.

Scalability

• Unknown
  • Could be scalable first with implementation on ships (e.g., Crook et al. 2016), but that relies on developing appropriate infrastructure. This field could benefit from technologies developed to reduce drag of ships.

• Unknown
  • Microbubble concentrates of ∼80,000–100,000 ppmv produced by commercial hydrosol generators have the potential to double the albedo even when diluted by a factor of 10³–10⁴ (Seitz 2011).
  • Reflective foams tested by Aziz et al. 2014 had lifetimes of 3 months without wave action.

• Unknown, will require:
  • Development of a non-toxic, inert surfactant with no impact on living organisms that increases ocean albedo
  • Development of deployment device

• • Unknown

• • Unknown

Cost

• Unknown
  • Estimated cost of surfactants to stabilize microbubbles is <$10/kg, or <$100 km⁻¹ (Seitz 2011).
  • Additional costs would be incurred in deployment, likely by ships.

• Unknown
  • A study by Ortega and Evans (2019) looked at energy required to maintain foams in the open ocean and proposed using energy derived from wave, wind, solar, or ship lubrication compressor power. They also suggested matching surfactant additions with infrastructure on ships.

Impact on

• Global low latitude studies increased from 0.05-0.1 to 0.15 (Gabriel et al. 2017); Arctic studies increased from 0.3-0.4 to 0.8 (Mengis et al. 2016)
  • Modeling study looked at increasing albedo to 0.15 over three subtropical ocean gyres in Southern Hemisphere (could not find estimate of total foamed area; Gabriel et al. 2017). Calm seas have albedo 0.05-0.1, bubbles of ocean whitecaps albedo 0.22 (Moore et al. 2000 cited in Seitz 2011).
  • Modeling study of Arctic Ocean looked at surface albedo of 0.8, model’s default value for sea ice, whenever sea ice concentration dropped below 50% in Arctic grid cells (Mengis et al. 2016). Additional study in the Arctic region adjusted ocean albedo to 0.7-0.9 across simulations (Cvjanovic et al. 2015).

• Global
  • Estimates of global average surface temperature decreases from 0.0-2.7°C, dependent on the area of deployment (Seitz 2011, Cvijanovic et al. 2015, Crook et al. 2016, Mengis et al. 2016, Gabriel et al. 2017). Arctic specific deployments have little potential to decrease global temperature (Cvijanovic et al. 2015, Mengis et al. 2016).
    • Model of global deployment over all seawater increasing albedo by 0.05 yielded estimate of a decrease in temperature of 7°C (Seitz 2011). Some areas saw cooling over 5°C.
    • A later model focused on deployment in subtropical gyres in the Southern Hemisphere with albedo set to 0.15 gave global mean surface temperature decrease of 0.53°C over 2030-2069 (Gabriel et al. 2017).
    • Increasing albedo by 0.2 in ship wakes of existing shipping lanes in model yields 0.5°C reduction in global mean temperature (Crook et al. 2016).
    • Targeted modeling studies of deployment in the Arctic Ocean estimated no change or a slight reduction in global mean temperature (Cvijanovic et al. 2015, Mengis et al. 2016).
• Arctic region
  • Modeling studies with targeted Arctic Ocean deployments report temperature decreases in the Arctic of 1.2-2°C (Cvijanovic et al. 2015, Mengis et al. 2016). Deployment in the Southern Hemisphere decreased temperatures in the Arctic by 0-1 °C (Gabriel et al. 2017).

• Global
  • Decreased radiative forcing of 0.9 – 1.5 W/m² (Crook et al. 2016, Gabriel et al. 2017)
    • Increasing albedo of ship wakes in existing shipping lanes decreased radiative forcing by 0.9 ±6 W/m² globally and 1.8 ± 0.9 W/m² in the Northern Hemisphere; if wake lifetime were increased to 3 months, reduction could reach 3 W/m² (Crook et al. 2016).
    • Model of albedo set to 0.15 in subtropical gyres in the Southern Hemisphere gave global decrease in radiative forcing of 1.5 W/m².
• Arctic region
  • Reductions in solar energy absorption by 65-82 W/m² in summer (Mengis et al. 2016).
    • Modeling study of Arctic Ocean reports decreases in radiative forcing with albedo modification of 65 W/m² for RCP4.5 and 82 W/m² for RCP 8.5.

• Direct or indirect impact on sea ice?
  • Indirect impact on sea ice via reductions in radiative forcing and temperature
• New or old ice?
  • Temperature reductions could enhance production of new ice and prevent melting of existing ice
• Impact on sea ice
  • Increase in sea ice extent 40-53% and delayed summer sea ice decline by 25-60 yr
    • Modeling study of surface albedo alteration by Cvijanovic et al. 2015 in Arctic showed that sea ice extent will stabilize at 40% of preindustrial value, compared to 3% without albedo modifications.
    • Modeling study of ocean albedo modification by Mengis et al. 2016 delays Arctic sea ice decline by 25-60 years depending on emissions scenario. 53% of summer sea ice area is maintained with ocean albedo modification compared to 27% without ocean albedo modification (compared to 2005-2015). Ice thickness increases as well with ocean albedo modification in these simulations.

Scalability

• Unknown
  • Could be scalable first with implementation on ships (e.g., Crook et al. 2016), but that relies on developing appropriate infrastructure. This field could benefit from technologies developed to reduce drag of ships.

• Unknown
  • Microbubble concentrates of ∼80,000–100,000 ppmv produced by commercial hydrosol generators have the potential to double the albedo even when diluted by a factor of 10³–10⁴ (Seitz 2011).
  • Reflective foams tested by Aziz et al. 2014 had lifetimes of 3 months without wave action.

• Unknown, will require:
  • Development of a non-toxic, inert surfactant with no impact on living organisms that increases ocean albedo
  • Development of deployment device

• • Unknown

• • Unknown

Cost

• Unknown
  • Estimated cost of surfactants to stabilize microbubbles is <$10/kg, or <$100 km⁻¹ (Seitz 2011).
  • Additional costs would be incurred in deployment, likely by ships.

• Unknown
  • A study by Ortega and Evans (2019) looked at energy required to maintain foams in the open ocean and proposed using energy derived from wave, wind, solar, or ship lubrication compressor power. They also suggested matching surfactant additions with infrastructure on ships.

Impact on

• Global low latitude studies increased from 0.05-0.1 to 0.15 (Gabriel et al. 2017); Arctic studies increased from 0.3-0.4 to 0.8 (Mengis et al. 2016)
  • Modeling study looked at increasing albedo to 0.15 over three subtropical ocean gyres in Southern Hemisphere (could not find estimate of total foamed area; Gabriel et al. 2017). Calm seas have albedo 0.05-0.1, bubbles of ocean whitecaps albedo 0.22 (Moore et al. 2000 cited in Seitz 2011).
  • Modeling study of Arctic Ocean looked at surface albedo of 0.8, model’s default value for sea ice, whenever sea ice concentration dropped below 50% in Arctic grid cells (Mengis et al. 2016). Additional study in the Arctic region adjusted ocean albedo to 0.7-0.9 across simulations (Cvjanovic et al. 2015).

• Global
  • Estimates of global average surface temperature decreases from 0.0-2.7°C, dependent on the area of deployment (Seitz 2011, Cvijanovic et al. 2015, Crook et al. 2016, Mengis et al. 2016, Gabriel et al. 2017). Arctic specific deployments have little potential to decrease global temperature (Cvijanovic et al. 2015, Mengis et al. 2016).
    • Model of global deployment over all seawater increasing albedo by 0.05 yielded estimate of a decrease in temperature of 7°C (Seitz 2011). Some areas saw cooling over 5°C.
    • A later model focused on deployment in subtropical gyres in the Southern Hemisphere with albedo set to 0.15 gave global mean surface temperature decrease of 0.53°C over 2030-2069 (Gabriel et al. 2017).
    • Increasing albedo by 0.2 in ship wakes of existing shipping lanes in model yields 0.5°C reduction in global mean temperature (Crook et al. 2016).
    • Targeted modeling studies of deployment in the Arctic Ocean estimated no change or a slight reduction in global mean temperature (Cvijanovic et al. 2015, Mengis et al. 2016).
• Arctic region
  • Modeling studies with targeted Arctic Ocean deployments report temperature decreases in the Arctic of 1.2-2°C (Cvijanovic et al. 2015, Mengis et al. 2016). Deployment in the Southern Hemisphere decreased temperatures in the Arctic by 0-1 °C (Gabriel et al. 2017).

• Global
  • Decreased radiative forcing of 0.9 – 1.5 W/m² (Crook et al. 2016, Gabriel et al. 2017)
    • Increasing albedo of ship wakes in existing shipping lanes decreased radiative forcing by 0.9 ±6 W/m² globally and 1.8 ± 0.9 W/m² in the Northern Hemisphere; if wake lifetime were increased to 3 months, reduction could reach 3 W/m² (Crook et al. 2016).
    • Model of albedo set to 0.15 in subtropical gyres in the Southern Hemisphere gave global decrease in radiative forcing of 1.5 W/m².
• Arctic region
  • Reductions in solar energy absorption by 65-82 W/m² in summer (Mengis et al. 2016).
    • Modeling study of Arctic Ocean reports decreases in radiative forcing with albedo modification of 65 W/m² for RCP4.5 and 82 W/m² for RCP 8.5.

• Direct or indirect impact on sea ice?
  • Indirect impact on sea ice via reductions in radiative forcing and temperature
• New or old ice?
  • Temperature reductions could enhance production of new ice and prevent melting of existing ice
• Impact on sea ice
  • Increase in sea ice extent 40-53% and delayed summer sea ice decline by 25-60 yr
    • Modeling study of surface albedo alteration by Cvijanovic et al. 2015 in Arctic showed that sea ice extent will stabilize at 40% of preindustrial value, compared to 3% without albedo modifications.
    • Modeling study of ocean albedo modification by Mengis et al. 2016 delays Arctic sea ice decline by 25-60 years depending on emissions scenario. 53% of summer sea ice area is maintained with ocean albedo modification compared to 27% without ocean albedo modification (compared to 2005-2015). Ice thickness increases as well with ocean albedo modification in these simulations.

Scalability

• Unknown
  • Could be scalable first with implementation on ships (e.g., Crook et al. 2016), but that relies on developing appropriate infrastructure. This field could benefit from technologies developed to reduce drag of ships.

• Unknown
  • Microbubble concentrates of ∼80,000–100,000 ppmv produced by commercial hydrosol generators have the potential to double the albedo even when diluted by a factor of 10³–10⁴ (Seitz 2011).
  • Reflective foams tested by Aziz et al. 2014 had lifetimes of 3 months without wave action.

• Unknown, will require:
  • Development of a non-toxic, inert surfactant with no impact on living organisms that increases ocean albedo
  • Development of deployment device

• • Unknown

• • Unknown

Cost

• Unknown
  • Estimated cost of surfactants to stabilize microbubbles is <$10/kg, or <$100 km⁻¹ (Seitz 2011).
  • Additional costs would be incurred in deployment, likely by ships.

• Unknown
  • A study by Ortega and Evans (2019) looked at energy required to maintain foams in the open ocean and proposed using energy derived from wave, wind, solar, or ship lubrication compressor power. They also suggested matching surfactant additions with infrastructure on ships.

Impact on

• Global low latitude studies increased from 0.05-0.1 to 0.15 (Gabriel et al. 2017); Arctic studies increased from 0.3-0.4 to 0.8 (Mengis et al. 2016)
  • Modeling study looked at increasing albedo to 0.15 over three subtropical ocean gyres in Southern Hemisphere (could not find estimate of total foamed area; Gabriel et al. 2017). Calm seas have albedo 0.05-0.1, bubbles of ocean whitecaps albedo 0.22 (Moore et al. 2000 cited in Seitz 2011).
  • Modeling study of Arctic Ocean looked at surface albedo of 0.8, model’s default value for sea ice, whenever sea ice concentration dropped below 50% in Arctic grid cells (Mengis et al. 2016). Additional study in the Arctic region adjusted ocean albedo to 0.7-0.9 across simulations (Cvjanovic et al. 2015).

• Global
  • Estimates of global average surface temperature decreases from 0.0-2.7°C, dependent on the area of deployment (Seitz 2011, Cvijanovic et al. 2015, Crook et al. 2016, Mengis et al. 2016, Gabriel et al. 2017). Arctic specific deployments have little potential to decrease global temperature (Cvijanovic et al. 2015, Mengis et al. 2016).
    • Model of global deployment over all seawater increasing albedo by 0.05 yielded estimate of a decrease in temperature of 7°C (Seitz 2011). Some areas saw cooling over 5°C.
    • A later model focused on deployment in subtropical gyres in the Southern Hemisphere with albedo set to 0.15 gave global mean surface temperature decrease of 0.53°C over 2030-2069 (Gabriel et al. 2017).
    • Increasing albedo by 0.2 in ship wakes of existing shipping lanes in model yields 0.5°C reduction in global mean temperature (Crook et al. 2016).
    • Targeted modeling studies of deployment in the Arctic Ocean estimated no change or a slight reduction in global mean temperature (Cvijanovic et al. 2015, Mengis et al. 2016).
• Arctic region
  • Modeling studies with targeted Arctic Ocean deployments report temperature decreases in the Arctic of 1.2-2°C (Cvijanovic et al. 2015, Mengis et al. 2016). Deployment in the Southern Hemisphere decreased temperatures in the Arctic by 0-1 °C (Gabriel et al. 2017).

• Global
  • Decreased radiative forcing of 0.9 – 1.5 W/m² (Crook et al. 2016, Gabriel et al. 2017)
    • Increasing albedo of ship wakes in existing shipping lanes decreased radiative forcing by 0.9 ±6 W/m² globally and 1.8 ± 0.9 W/m² in the Northern Hemisphere; if wake lifetime were increased to 3 months, reduction could reach 3 W/m² (Crook et al. 2016).
    • Model of albedo set to 0.15 in subtropical gyres in the Southern Hemisphere gave global decrease in radiative forcing of 1.5 W/m².
• Arctic region
  • Reductions in solar energy absorption by 65-82 W/m² in summer (Mengis et al. 2016).
    • Modeling study of Arctic Ocean reports decreases in radiative forcing with albedo modification of 65 W/m² for RCP4.5 and 82 W/m² for RCP 8.5.

• Direct or indirect impact on sea ice?
  • Indirect impact on sea ice via reductions in radiative forcing and temperature
• New or old ice?
  • Temperature reductions could enhance production of new ice and prevent melting of existing ice
• Impact on sea ice
  • Increase in sea ice extent 40-53% and delayed summer sea ice decline by 25-60 yr
    • Modeling study of surface albedo alteration by Cvijanovic et al. 2015 in Arctic showed that sea ice extent will stabilize at 40% of preindustrial value, compared to 3% without albedo modifications.
    • Modeling study of ocean albedo modification by Mengis et al. 2016 delays Arctic sea ice decline by 25-60 years depending on emissions scenario. 53% of summer sea ice area is maintained with ocean albedo modification compared to 27% without ocean albedo modification (compared to 2005-2015). Ice thickness increases as well with ocean albedo modification in these simulations.

Scalability

• Unknown
  • Could be scalable first with implementation on ships (e.g., Crook et al. 2016), but that relies on developing appropriate infrastructure. This field could benefit from technologies developed to reduce drag of ships.

• Unknown
  • Microbubble concentrates of ∼80,000–100,000 ppmv produced by commercial hydrosol generators have the potential to double the albedo even when diluted by a factor of 103–10⁴ (Seitz 2011).
  • Reflective foams tested by Aziz et al. 2014 had lifetimes of 3 months without wave action.

• Unknown, will require:
  • Development of a non-toxic, inert surfactant with no impact on living organisms that increases ocean albedo
  • Development of deployment device

• • Unknown

• • Unknown

Cost

• Unknown
  • Estimated cost of surfactants to stabilize microbubbles is <$10/kg, or <$100 km⁻¹ (Seitz 2011).
  • Additional costs would be incurred in deployment, likely by ships.

• Unknown
  • A study by Ortega and Evans (2019) looked at energy required to maintain foams in the open ocean and proposed using energy derived from wave, wind, solar, or ship lubrication compressor power. They also suggested matching surfactant additions with infrastructure on ships.

Impact on

• Global low latitude studies increased from 0.05-0.1 to 0.15 (Gabriel et al. 2017); Arctic studies increased from 0.3-0.4 to 0.8 (Mengis et al. 2016)
  • Modeling study looked at increasing albedo to 0.15 over three subtropical ocean gyres in Southern Hemisphere (could not find estimate of total foamed area; Gabriel et al. 2017). Calm seas have albedo 0.05-0.1, bubbles of ocean whitecaps albedo 0.22 (Moore et al. 2000 cited in Seitz 2011).
  • Modeling study of Arctic Ocean looked at surface albedo of 0.8, model’s default value for sea ice, whenever sea ice concentration dropped below 50% in Arctic grid cells (Mengis et al. 2016). Additional study in the Arctic region adjusted ocean albedo to 0.7-0.9 across simulations (Cvjanovic et al. 2015).

• Global
  • Estimates of global average surface temperature decreases from 0.0-2.7°C, dependent on the area of deployment (Seitz 2011, Cvijanovic et al. 2015, Crook et al. 2016, Mengis et al. 2016, Gabriel et al. 2017). Arctic specific deployments have little potential to decrease global temperature (Cvijanovic et al. 2015, Mengis et al. 2016).
    • Model of global deployment over all seawater increasing albedo by 0.05 yielded estimate of a decrease in temperature of 7°C (Seitz 2011). Some areas saw cooling over 5°C.
    • A later model focused on deployment in subtropical gyres in the Southern Hemisphere with albedo set to 0.15 gave global mean surface temperature decrease of 0.53°C over 2030-2069 (Gabriel et al. 2017).
    • Increasing albedo by 0.2 in ship wakes of existing shipping lanes in model yields 0.5°C reduction in global mean temperature (Crook et al. 2016).
    • Targeted modeling studies of deployment in the Arctic Ocean estimated no change or a slight reduction in global mean temperature (Cvijanovic et al. 2015, Mengis et al. 2016).
• Arctic region
  • Modeling studies with targeted Arctic Ocean deployments report temperature decreases in the Arctic of 1.2-2°C (Cvijanovic et al. 2015, Mengis et al. 2016). Deployment in the Southern Hemisphere decreased temperatures in the Arctic by 0-1 °C (Gabriel et al. 2017).

• Global
  • Decreased radiative forcing of 0.9 – 1.5 W/m² (Crook et al. 2016, Gabriel et al. 2017)
    • Increasing albedo of ship wakes in existing shipping lanes decreased radiative forcing by 0.9 ±6 W/m² globally and 1.8 ± 0.9 W/m² in the Northern Hemisphere; if wake lifetime were increased to 3 months, reduction could reach 3 W/m² (Crook et al. 2016).
    • Model of albedo set to 0.15 in subtropical gyres in the Southern Hemisphere gave global decrease in radiative forcing of 1.5 W/m².
• Arctic region
  • Reductions in solar energy absorption by 65-82 W/m² in summer (Mengis et al. 2016).
    • Modeling study of Arctic Ocean reports decreases in radiative forcing with albedo modification of 65 W/m² for RCP4.5 and 82 W/m² for RCP 8.5.

• Direct or indirect impact on sea ice?
  • Indirect impact on sea ice via reductions in radiative forcing and temperature
• New or old ice?
  • Temperature reductions could enhance production of new ice and prevent melting of existing ice
• Impact on sea ice
  • Increase in sea ice extent 40-53% and delayed summer sea ice decline by 25-60 yr
    • Modeling study of surface albedo alteration by Cvijanovic et al. 2015 in Arctic showed that sea ice extent will stabilize at 40% of preindustrial value, compared to 3% without albedo modifications.
    • Modeling study of ocean albedo modification by Mengis et al. 2016 delays Arctic sea ice decline by 25-60 years depending on emissions scenario. 53% of summer sea ice area is maintained with ocean albedo modification compared to 27% without ocean albedo modification (compared to 2005-2015). Ice thickness increases as well with ocean albedo modification in these simulations.

Scalability

• Unknown
  • Could be scalable first with implementation on ships (e.g., Crook et al. 2016), but that relies on developing appropriate infrastructure. This field could benefit from technologies developed to reduce drag of ships.

• Unknown
  • Microbubble concentrates of ∼80,000–100,000 ppmv produced by commercial hydrosol generators have the potential to double the albedo even when diluted by a factor of 10³–10⁴ (Seitz 2011).
  • Reflective foams tested by Aziz et al. 2014 had lifetimes of 3 months without wave action.

• Unknown, will require:
  • Development of a non-toxic, inert surfactant with no impact on living organisms that increases ocean albedo
  • Development of deployment device

• • Unknown

• • Unknown

Cost

• Unknown
  • Estimated cost of surfactants to stabilize microbubbles is <$10/kg, or <$100 km⁻¹ (Seitz 2011).
  • Additional costs would be incurred in deployment, likely by ships.

• Unknown
  • A study by Ortega and Evans (2019) looked at energy required to maintain foams in the open ocean and proposed using energy derived from wave, wind, solar, or ship lubrication compressor power. They also suggested matching surfactant additions with infrastructure on ships.

Impact on

• Global low latitude studies increased from 0.05-0.1 to 0.15 (Gabriel et al. 2017); Arctic studies increased from 0.3-0.4 to 0.8 (Mengis et al. 2016)
  • Modeling study looked at increasing albedo to 0.15 over three subtropical ocean gyres in Southern Hemisphere (could not find estimate of total foamed area; Gabriel et al. 2017). Calm seas have albedo 0.05-0.1, bubbles of ocean whitecaps albedo 0.22 (Moore et al. 2000 cited in Seitz 2011).
  • Modeling study of Arctic Ocean looked at surface albedo of 0.8, model’s default value for sea ice, whenever sea ice concentration dropped below 50% in Arctic grid cells (Mengis et al. 2016). Additional study in the Arctic region adjusted ocean albedo to 0.7-0.9 across simulations (Cvjanovic et al. 2015).

• Global
  • Estimates of global average surface temperature decreases from 0.0-2.7°C, dependent on the area of deployment (Seitz 2011, Cvijanovic et al. 2015, Crook et al. 2016, Mengis et al. 2016, Gabriel et al. 2017). Arctic specific deployments have little potential to decrease global temperature (Cvijanovic et al. 2015, Mengis et al. 2016).
    • Model of global deployment over all seawater increasing albedo by 0.05 yielded estimate of a decrease in temperature of 7°C (Seitz 2011). Some areas saw cooling over 5°C.
    • A later model focused on deployment in subtropical gyres in the Southern Hemisphere with albedo set to 0.15 gave global mean surface temperature decrease of 0.53°C over 2030-2069 (Gabriel et al. 2017).
    • Increasing albedo by 0.2 in ship wakes of existing shipping lanes in model yields 0.5°C reduction in global mean temperature (Crook et al. 2016).
    • Targeted modeling studies of deployment in the Arctic Ocean estimated no change or a slight reduction in global mean temperature (Cvijanovic et al. 2015, Mengis et al. 2016).
• Arctic region
  • Modeling studies with targeted Arctic Ocean deployments report temperature decreases in the Arctic of 1.2-2°C (Cvijanovic et al. 2015, Mengis et al. 2016). Deployment in the Southern Hemisphere decreased temperatures in the Arctic by 0-1 °C (Gabriel et al. 2017).

• Global
  • Decreased radiative forcing of 0.9 – 1.5 W/m² (Crook et al. 2016, Gabriel et al. 2017)
    • Increasing albedo of ship wakes in existing shipping lanes decreased radiative forcing by 0.9 ±6 W/m² globally and 1.8 ± 0.9 W/m² in the Northern Hemisphere; if wake lifetime were increased to 3 months, reduction could reach 3 W/m² (Crook et al. 2016).
    • Model of albedo set to 0.15 in subtropical gyres in the Southern Hemisphere gave global decrease in radiative forcing of 1.5 W/m².
• Arctic region
  • Reductions in solar energy absorption by 65-82 W/m² in summer (Mengis et al. 2016).
    • Modeling study of Arctic Ocean reports decreases in radiative forcing with albedo modification of 65 W/m² for RCP4.5 and 82 W/m² for RCP 8.5.

• Direct or indirect impact on sea ice?
  • Indirect impact on sea ice via reductions in radiative forcing and temperature
• New or old ice?
  • Temperature reductions could enhance production of new ice and prevent melting of existing ice
• Impact on sea ice
  • Increase in sea ice extent 40-53% and delayed summer sea ice decline by 25-60 yr
    • Modeling study of surface albedo alteration by Cvijanovic et al. 2015 in Arctic showed that sea ice extent will stabilize at 40% of preindustrial value, compared to 3% without albedo modifications.
    • Modeling study of ocean albedo modification by Mengis et al. 2016 delays Arctic sea ice decline by 25-60 years depending on emissions scenario. 53% of summer sea ice area is maintained with ocean albedo modification compared to 27% without ocean albedo modification (compared to 2005-2015). Ice thickness increases as well with ocean albedo modification in these simulations.

Scalability

• Unknown
  • Could be scalable first with implementation on ships (e.g., Crook et al. 2016), but that relies on developing appropriate infrastructure. This field could benefit from technologies developed to reduce drag of ships.

• Unknown
  • Microbubble concentrates of ∼80,000–100,000 ppmv produced by commercial hydrosol generators have the potential to double the albedo even when diluted by a factor of 10³–10⁴ (Seitz 2011).
  • Reflective foams tested by Aziz et al. 2014 had lifetimes of 3 months without wave action.

• Unknown, will require:
  • Development of a non-toxic, inert surfactant with no impact on living organisms that increases ocean albedo
  • Development of deployment device

• • Unknown

• • Unknown

Cost

• Unknown
  • Estimated cost of surfactants to stabilize microbubbles is <$10/kg, or <$100 km⁻¹ (Seitz 2011).
  • Additional costs would be incurred in deployment, likely by ships.

• Unknown
  • A study by Ortega and Evans (2019) looked at energy required to maintain foams in the open ocean and proposed using energy derived from wave, wind, solar, or ship lubrication compressor power. They also suggested matching surfactant additions with infrastructure on ships.

Impact on

• Global low latitude studies increased from 0.05-0.1 to 0.15 (Gabriel et al. 2017); Arctic studies increased from 0.3-0.4 to 0.8 (Mengis et al. 2016)
  • Modeling study looked at increasing albedo to 0.15 over three subtropical ocean gyres in Southern Hemisphere (could not find estimate of total foamed area; Gabriel et al. 2017). Calm seas have albedo 0.05-0.1, bubbles of ocean whitecaps albedo 0.22 (Moore et al. 2000 cited in Seitz 2011).
  • Modeling study of Arctic Ocean looked at surface albedo of 0.8, model’s default value for sea ice, whenever sea ice concentration dropped below 50% in Arctic grid cells (Mengis et al. 2016). Additional study in the Arctic region adjusted ocean albedo to 0.7-0.9 across simulations (Cvjanovic et al. 2015).

• Global
  • Estimates of global average surface temperature decreases from 0.0-2.7°C, dependent on the area of deployment (Seitz 2011, Cvijanovic et al. 2015, Crook et al. 2016, Mengis et al. 2016, Gabriel et al. 2017). Arctic specific deployments have little potential to decrease global temperature (Cvijanovic et al. 2015, Mengis et al. 2016).
    • Model of global deployment over all seawater increasing albedo by 0.05 yielded estimate of a decrease in temperature of 7°C (Seitz 2011). Some areas saw cooling over 5°C.
    • A later model focused on deployment in subtropical gyres in the Southern Hemisphere with albedo set to 0.15 gave global mean surface temperature decrease of 0.53°C (Gabriel et al. 2017).
    • Increasing albedo by 0.2 in ship wakes of existing shipping lanes in model yields 0.5°C reduction in global mean temperature (Crook et al. 2016).
    • Targeted modeling studies of deployment in the Arctic Ocean estimated no change or a slight reduction in global mean temperature (Cvijanovic et al. 2015, Mengis et al. 2016).
• Arctic region
  • Modeling studies with targeted Arctic Ocean deployments report temperature decreases in the Arctic of 1.2-2°C (Cvijanovic et al. 2015, Mengis et al. 2016). Deployment in the Southern Hemisphere decreased temperatures in the Arctic by 0-1 °C (Gabriel et al. 2017).

• Global
  • Decreased radiative forcing of 0.9 – 1.5 W/m² (Crook et al. 2016, Gabriel et al. 2017)
    • Increasing albedo of ship wakes in existing shipping lanes decreased radiative forcing by 0.9 ±6 W/m² globally and 1.8 ± 0.9 W/m² in the Northern Hemisphere; if wake lifetime were increased to 3 months, reduction could reach 3 W/m² (Crook et al. 2016).
    • Model of albedo set to 0.15 in subtropical gyres in the Southern Hemisphere gave global decrease in radiative forcing of 1.5 W/m².
• Arctic region
  • Reductions in solar energy absorption by 65-82 W/m² in summer (Mengis et al. 2016).
    • Modeling study of Arctic Ocean reports decreases in radiative forcing with albedo modification of 65 W/m² for RCP4.5 and 82 W/m² for RCP 8.5.

• Direct or indirect impact on sea ice?
  • Indirect impact on sea ice via reductions in radiative forcing and temperature
• New or old ice?
  • Temperature reductions could enhance production of new ice and prevent melting of existing ice
• Impact on sea ice
  • Increase in sea ice extent 40-53% and delayed summer sea ice decline by 25-60 yr
    • Modeling study of surface albedo alteration by Cvijanovic et al. 2015 in Arctic showed that sea ice extent will stabilize at 40% of preindustrial value, compared to 3% without albedo modifications.
    • Modeling study of ocean albedo modification by Mengis et al. 2016 delays Arctic sea ice decline by 25-60 years depending on emissions scenario. 53% of summer sea ice area is maintained with ocean albedo modification compared to 27% without ocean albedo modification (compared to 2005-2015). Ice thickness increases as well with ocean albedo modification in these simulations.

Scalability

• Unknown
  • Could be scalable first with implementation on ships (e.g., Crook et al. 2016), but that relies on developing appropriate infrastructure. This field could benefit from technologies developed to reduce drag of ships.

• Unknown
  • Microbubble concentrates of ∼80,000–100,000 ppmv produced by commercial hydrosol generators have the potential to double the albedo even when diluted by a factor of 10³–10⁴ (Seitz 2011).
  • Reflective foams tested by Aziz et al. 2014 had lifetimes of 3 months without wave action.

• Unknown, will require:
  • Development of a non-toxic, inert surfactant with no impact on living organisms that increases ocean albedo
  • Development of deployment device

• • Unknown

• • Unknown

Cost

• Unknown
  • Estimated cost of surfactants to stabilize microbubbles is <$10/kg, or <$100 km⁻¹ (Seitz 2011).
  • Additional costs would be incurred in deployment, likely by ships.

• Unknown
  • A study by Ortega and Evans (2019) looked at energy required to maintain foams in the open ocean and proposed using energy derived from wave, wind, solar, or ship lubrication compressor power. They also suggested matching surfactant additions with infrastructure on ships.

Impact on

• Global low latitude studies increased from 0.05-0.1 to 0.15 (Gabriel et al. 2017); Arctic studies increased from 0.3-0.4 to 0.8 (Mengis et al. 2016)
  • Modeling study looked at increasing albedo to 0.15 over three subtropical ocean gyres in Southern Hemisphere (could not find estimate of total foamed area; Gabriel et al. 2017). Calm seas have albedo 0.05-0.1, bubbles of ocean whitecaps albedo 0.22 (Moore et al. 2000 cited in Seitz 2011).
  • Modeling study of Arctic Ocean looked at surface albedo of 0.8, model’s default value for sea ice, whenever sea ice concentration dropped below 50% in Arctic grid cells (Mengis et al. 2016). Additional study in the Arctic region adjusted ocean albedo to 0.7-0.9 across simulations (Cvjanovic et al. 2015).

• Global
  • Estimates of global average surface temperature decreases from 0.0-2.7°C, dependent on the area of deployment (Seitz 2011, Cvijanovic et al. 2015, Crook et al. 2016, Mengis et al. 2016, Gabriel et al. 2017). Arctic specific deployments have little potential to decrease global temperature (Cvijanovic et al. 2015, Mengis et al. 2016).
    • Model of global deployment over all seawater increasing albedo by 0.05 yielded estimate of a decrease in temperature of 7°C (Seitz 2011). Some areas saw cooling over 5°C.
    • A later model focused on deployment in subtropical gyres in the Southern Hemisphere with albedo set to 0.15 gave global mean surface temperature decrease of 0.53°C (Gabriel et al. 2017).
    • Increasing albedo by 0.2 in ship wakes of existing shipping lanes in model yields 0.5°C reduction in global mean temperature (Crook et al. 2016).
    • Targeted modeling studies of deployment in the Arctic Ocean estimated no change or a slight reduction in global mean temperature (Cvijanovic et al. 2015, Mengis et al. 2016).
• Arctic region
  • Modeling studies with targeted Arctic Ocean deployments report temperature decreases in the Arctic of 1.2-2°C (Cvijanovic et al. 2015, Mengis et al. 2016). Deployment in the Southern Hemisphere decreased temperatures in the Arctic by 0-1 °C (Gabriel et al. 2017).

• Global
  • Decreased radiative forcing of 0.9 – 1.5 W/m² (Crook et al. 2016, Gabriel et al. 2017)
    • Increasing albedo of ship wakes in existing shipping lanes decreased radiative forcing by 0.9 ±6 W/m² globally and 1.8 ± 0.9 W/m² in the Northern Hemisphere; if wake lifetime were increased to 3 months, reduction could reach 3 W/m² (Crook et al. 2016).
    • Model of albedo set to 0.15 in subtropical gyres in the Southern Hemisphere gave global decrease in radiative forcing of 1.5 W/m².
• Arctic region
  • Reductions in solar energy absorption by 65-82 W/m² in summer (Mengis et al. 2016).
    • Modeling study of Arctic Ocean reports decreases in radiative forcing with albedo modification of 65 W/m² for RCP4.5 and 82 W/m² for RCP 8.5.

• Direct or indirect impact on sea ice?
  • Indirect impact on sea ice via reductions in radiative forcing and temperature
• New or old ice?
  • Temperature reductions could enhance production of new ice and prevent melting of existing ice
• Impact on sea ice
  • Increase in sea ice extent 40-53% and delayed summer sea ice decline by 25-60 yr
    • Modeling study of surface albedo alteration by Cvijanovic et al. 2015 in Arctic showed that sea ice extent will stabilize at 40% of preindustrial value, compared to 3% without albedo modifications.
    • Modeling study of ocean albedo modification by Mengis et al. 2016 delays Arctic sea ice decline by 25-60 years depending on emissions scenario. 53% of summer sea ice area is maintained with ocean albedo modification compared to 27% without ocean albedo modification (compared to 2005-2015). Ice thickness increases as well with ocean albedo modification in these simulations.

Scalability

• Unknown
  • Could be scalable first with implementation on ships (e.g., Crook et al. 2016), but that relies on developing appropriate infrastructure. This field could benefit from technologies developed to reduce drag of ships.

• Unknown
  • Microbubble concentrates of ∼80,000–100,000 ppmv produced by commercial hydrosol generators have the potential to double the albedo even when diluted by a factor of 10³–10⁴ (Seitz 2011).
  • Reflective foams tested by Aziz et al. 2014 had lifetimes of 3 months without wave action.

• Unknown, will require:
  • Development of a non-toxic, inert surfactant with no impact on living organisms that increases ocean albedo
  • Development of deployment device

• • Unknown

• • Unknown

Cost

• Unknown
  • Estimated cost of surfactants to stabilize microbubbles is <$10/kg, or <$100 km⁻¹ (Seitz 2011).
  • Additional costs would be incurred in deployment, likely by ships.

• Unknown
  • A study by Ortega and Evans (2019) looked at energy required to maintain foams in the open ocean and proposed using energy derived from wave, wind, solar, or ship lubrication compressor power. They also suggested matching surfactant additions with infrastructure on ships.

Impact on

• Global low latitude studies increased from 0.05-0.1 to 0.15 (Gabriel et al. 2017); Arctic studies increased from 0.3-0.4 to 0.8 (Mengis et al. 2016)
  • Modeling study looked at increasing albedo to 0.15 over three subtropical ocean gyres in Southern Hemisphere (could not find estimate of total foamed area; Gabriel et al. 2017). Calm seas have albedo 0.05-0.1, bubbles of ocean whitecaps albedo 0.22 (Moore et al. 2000 cited in Seitz 2011)
  • Modeling study of Arctic Ocean looked at surface albedo of 0.8, model’s default value for sea ice, whenever sea ice concentration dropped below 50% in Arctic grid cells (Mengis et al. 2016). Additional study in the Arctic region adjusted ocean albedo to 0.7-0.9 across simulations (Cvjanovic et al. 2015).

• Global
  • Estimates of global average surface temperature decreases from 0.0-2.7°C, dependent on the area of deployment (Seitz 2011, Cvijanovic et al. 2015, Crook et al. 2016, Mengis et al. 2016, Gabriel et al. 2017). Arctic specific deployments have little potential to decrease global temperature (Cvijanovic et al. 2015, Mengis et al. 2016).
    • Model of global deployment over all seawater increasing albedo by 0.05 yielded estimate of a decrease in temperature of 7°C (Seitz 2011). Some areas saw cooling over 5°C.
    • A later model focused on deployment in subtropical gyres in the Southern Hemisphere with albedo set to 0.15 gave global mean surface temperature decrease of 0.53°C (Gabriel et al. 2017).
    • Increasing albedo by 0.2 in ship wakes of existing shipping lanes in model yields 0.5°C reduction in global mean temperature (Crook et al. 2016).
    • Targeted modeling studies of deployment in the Arctic Ocean estimated no change or a slight reduction in global mean temperature (Cvijanovic et al. 2015, Mengis et al. 2016).
• Arctic region
  • Modeling studies with targeted Arctic Ocean deployments report temperature decreases in the Arctic of 1.2-2°C (Cvijanovic et al. 2015, Mengis et al. 2016). Deployment in the Southern Hemisphere decreased temperatures in the Arctic by 0-1 °C (Gabriel et al. 2017).

• Global
  • Decreased radiative forcing of 0.9 – 1.5 W/m² (Crook et al. 2016, Gabriel et al. 2017)
    • Increasing albedo of ship wakes in existing shipping lanes decreased radiative forcing by 0.9 ±6 W/m² globally and 1.8 ± 0.9 W/m² in the Northern Hemisphere; if wake lifetime were increased to 3 months, reduction could reach 3 W/m² (Crook et al. 2016).
    • Model of albedo set to 0.15 in subtropical gyres in the Southern Hemisphere gave global decrease in radiative forcing of 1.5 W/m².
• Arctic region
  • Reductions in solar energy absorption by 65-82 W/m² in summer (Mengis et al. 2016).
    • Modeling study of Arctic Ocean reports decreases in radiative forcing with albedo modification of 65 W/m² for RCP4.5 and 82 W/m² for RCP 8.5.

• Direct or indirect impact on sea ice?
  • Indirect impact on sea ice via reductions in radiative forcing and temperature
• New or old ice?
  • Temperature reductions could enhance production of new ice and prevent melting of existing ice
• Impact on sea ice
  • Increase in sea ice extent 40-53% and delayed summer sea ice decline by 25-60 yr
    • Modeling study of surface albedo alteration by Cvijanovic et al. 2015 in Arctic showed that sea ice extent will stabilize at 40% of preindustrial value, compared to 3% without albedo modifications.
    • Modeling study of ocean albedo modification by Mengis et al. 2016 delays Arctic sea ice decline by 25-60 years depending on emissions scenario. 53% of summer sea ice area is maintained with ocean albedo modification compared to 27% without ocean albedo modification (compared to 2005-2015). Ice thickness increases as well with ocean albedo modification in these simulations.

Scalability

• Unknown
  • Could be scalable first with implementation on ships (e.g., Crook et al. 2016), but that relies on developing appropriate infrastructure. This field could benefit from technologies developed to reduce drag of ships.

• Unknown
  • Microbubble concentrates of ∼80,000–100,000 ppmv produced by commercial hydrosol generators have the potential to double the albedo even when diluted by a factor of 10³–10⁴ (Seitz 2011).
  • Reflective foams tested by Aziz et al. 2014 had lifetimes of 3 months without wave action.

• Unknown, will require:
  • Development of a non-toxic, inert surfactant with no impact on living organisms that increases ocean albedo
  • Development of deployment device

• • Unknown

• • Unknown

Cost

• Unknown
  • Estimated cost of surfactants to stabilize microbubbles is <$10/kg, or <$100 km⁻¹ (Seitz 2011).
  • Additional costs would be incurred in deployment, likely by ships.

• Unknown
  • A study by Ortega and Evans (2019) looked at energy required to maintain foams in the open ocean and proposed using energy derived from wave, wind, solar, or ship lubrication compressor power. They also suggested matching surfactant additions with infrastructure on ships.

• 2 – theoretical and modeling studies, some testing of foams in laboratory setting
  • Summary of existing literature and studies:
    • Theoretical exploration in Seitz 2011 with modeling case study.
    • Some laboratory studies on microbubbles described by Seitz 2011.
    • Modeling study of subtropics in Southern Hemisphere by Gabriel et al. 2017.
    • Foam developed and tested in laboratory but not outside (Aziz et al. 2014).
      • One foam tested, iota carrageenan, is derived from seaweed.
      • Foams tested in Aziz et al. 2014 had measured reflectance of 0.65-0.75.
    • Modeling studies of albedo modification in ice free Arctic Ocean (Cvijanovic et al. 2015, Mengis et al. 2016).
    • Engineering required for foaming discussed in Evans et al. 2010.

• Unknown, to date no field testing.

• • 2 – theoretical and modeling studies, some testing of foams in laboratory setting
    • Summary of existing literature and studies:
      • Theoretical exploration in Seitz 2011 with modeling case study
      • Some laboratory studies on microbubbles described by Seitz 2011
      • Modeling study of subtropics in Southern Hemisphere by Gabriel et al. 2017
      • Foam developed and tested in laboratory but not outside (Aziz et al. 2014)
        • One foam tested, iota carrageenan, is derived from seaweed
        • Foams tested in Aziz et al. 2014 had measured reflectance of 0.65-0.75
      • Modeling studies of albedo modification in ice free Arctic Ocean (Cvijanovic et al. 2015, Mengis et al. 2016)
      • Engineering required for foaming discussed in Evans et al. 2010

• • Unknown, to date no field testing.

• TRL
  • 2 – theoretical and modeling studies, some testing of foams in laboratory setting
    • Summary of existing literature and studies:
      • Theoretical exploration in Seitz 2011 with modeling case study
      • Some laboratory studies on microbubbles described by Seitz 2011
      • Modeling study of subtropics in Southern Hemisphere by Gabriel et al. 2017
      • Foam developed and tested in laboratory but not outside (Aziz et al. 2014)
        • One foam tested, iota carrageenan, is derived from seaweed
        • Foams tested in Aziz et al. 2014 had measured reflectance of 0.65-0.75
      • Modeling studies of albedo modification in ice free Arctic Ocean (Cvijanovic et al. 2015, Mengis et al. 2016)
      • Engineering required for foaming discussed in Evans et al. 2010
• Technical feasibility within 10 yrs
  • Unknown, to date no field testing.

Physical and chemical changes

• Co-benefits
  • Potential for delayed permafrost thaw (Mengis et al. 2016).
  • Potential for increased rainfall over land (Gabriel et al. 2017).
    • Could complement SAI because SAI may weaken hydrological cycle.
  • Bubbles in ocean may launch seasalt aerosols that would also increase reflectivity of clouds (Evans et al. 2010, Crook et al. 2016).
  • A cooler ocean could make the ocean a more effective CO₂ sink (Robock 2011).
  • No risk to the ozone in the stratosphere, as compared with Stratospheric Aerosol Injection (Gabriel et al. 2017).
• Risks
  • Potential to impact ocean biogeochemistry with unknown consequences (Seitz 2011).
  • Potential to change impact vertical mixing in the ocean and alter ocean circulation (Robock 2011).
  • Bubbles and foam may change light availability (Robock 2011).
  • Unknown impacts on ocean circulation and evaporation which would impact atmospheric heating and circulation (Robock 2011).
  • Surfactants inhibit gas exchange at the ocean surface (Engel et al. 2017).
  • Subsurface warming in the Arctic from ocean albedo modification could potentially increase the risk of melting methane hydrates (Mengis et al. 2016).

Impacts on species

• Co-benefits
  • Unknown
• Risks
  • Unknown effects on phytoplankton (Seitz 2011). Links have been shown between phytoplankton exudates at the sea surface and cloud formation in the Arctic (Engel et al. 2017), suggesting that impacts of films on phytoplankton could have far-reaching effects.
  • Possible toxic effects on organisms if surfactants are used (Robock 2011).

Impacts on ecosystems

• Co-benefits
  • Unknown
• Risks
  • Unknown impacts on phytoplankton and primary production (Robock 2011, Seitz 2011). Deployment in low productivity waters may decrease risks (Gabriel et al. 2017).

Impacts on society

• Co-benefits
  • Unknown
  • Potential opportunity to leverage technologies increasing fuel efficiency of ships contributing to decarbonization.
• Risks
  • If surfactants are toxic and impact organisms, there could be toxic effects when consumed by humans.

Ease of reversibility

• Medium
  • Production of microbubbles could be terminated within days (Seitz 2011). However, if a surfactant were used, time would be needed to clean up the surfactant if that were even possible.

Risk of termination shock

• Medium
  • Modeling study shows return to background temperatures when bubbles are stopped in about 5 years (Gabriel et al. 2017).
  • Sea ice extent quickly reversed to match the sea ice extent of the default simulation in modeling study of the Arctic Ocean (Mengis et al. 2016).
  • If foams are deployed with surfactants to increase the lifetime of foams, the return to lower albedo will depend on the lifetime of the foam. Foam lifetimes of tested foams are up to months long (Aziz et al. 2014).

Physical and chemical changes

• Co-benefits
  • Potential for delayed permafrost thaw (Mengis et al. 2016).
  • Potential for increased rainfall over land (Gabriel et al. 2017).
    • Could complement SAI because SAI may weaken hydrological cycle.
  • Bubbles in ocean may launch seasalt aerosols that would also increase reflectivity of clouds (Evans et al. 2010, Crook et al. 2016).
  • A cooler ocean could make the ocean a more effective CO₂ sink (Robock 2011).
  • No risk to the ozone in the stratosphere, as compared with Stratospheric Aerosol Injection (Gabriel et al. 2017).
• Risks
  • Potential to impact ocean biogeochemistry with unknown consequences (Seitz 2011).
  • Potential to change impact vertical mixing in the ocean and alter ocean circulation (Robock 2011).
  • Bubbles and foam may change light availability (Robock 2011).
  • Unknown impacts on ocean circulation and evaporation which would impact atmospheric heating and circulation (Robock 2011).
  • Surfactants inhibit gas exchange at the ocean surface (Engel et al. 2017).
  • Subsurface warming in the Arctic from ocean albedo modification could potentially increase the risk of melting methane hydrates (Mengis et al. 2016).

Impacts on species

• Co-benefits
  • Unknown
• Risks
  • Unknown effects on phytoplankton (Seitz 2011). Links have been shown between phytoplankton exudates at the sea surface and cloud formation in the Arctic (Engel et al. 2017), suggesting that impacts of films on phytoplankton could have far-reaching effects.
  • Possible toxic effects on organisms if surfactants are used (Robock 2011).

Impacts on ecosystems

• Co-benefits
  • Unknown
• Risks
  • Unknown impacts on phytoplankton and primary production (Robock 2011, Seitz 2011). Deployment in low productivity waters may decrease risks (Gabriel et al. 2017).

Impacts on society

• Co-benefits
  • Unknown
  • Potential opportunity to leverage technologies increasing fuel efficiency of ships contributing to decarbonization.
• Risks
  • If surfactants are toxic and impact organisms, there could be toxic effects when consumed by humans.

Ease of reversibility

• Production of microbubbles could be terminated within days (Seitz 2011). However, if a surfactant were used, time would be needed to clean up the surfactant if that were even possible.

Risk of termination shock

• Modeling study shows return to background temperatures when bubbles are stopped in about 5 years (Gabriel et al. 2017).
• Sea ice extent quickly reversed to match the sea ice extent of the default simulation in modeling study of the Arctic Ocean (Mengis et al. 2016).
• If foams are deployed with surfactants to increase the lifetime of foams, the return to lower albedo will depend on the lifetime of the foam. Foam lifetimes of tested foams are up to months long (Aziz et al. 2014).

• Co-benefits
  • Potential for delayed permafrost thaw (Mengis et al. 2016).
  • Potential for increased rainfall over land (Gabriel et al. 2017).
    • Could complement SAI because SAI may weaken hydrological cycle.
  • Bubbles in ocean may launch seasalt aerosols that would also increase reflectivity of clouds (Evans et al. 2010, Crook et al. 2016).
  • A cooler ocean could make the ocean a more effective CO₂ sink (Robock 2011).
  • No risk to the ozone in the stratosphere, as compared with Stratospheric Aerosol Injection (Gabriel et al. 2017).
• Risks
  • Potential to impact ocean biogeochemistry with unknown consequences (Seitz 2011).
  • Potential to change impact vertical mixing in the ocean and alter ocean circulation (Robock 2011).
  • Bubbles and foam may change light availability (Robock 2011).
  • Unknown impacts on ocean circulation and evaporation which would impact atmospheric heating and circulation (Robock 2011).
  • Surfactants inhibit gas exchange at the ocean surface (Engel et al. 2017).
  • Subsurface warming in the Arctic from ocean albedo modification could potentially increase the risk of melting methane hydrates (Mengis et al. 2016).

• Co-benefits
  • Unknown
• Risks
  • Unknown effects on phytoplankton (Seitz 2011). Links have been shown between phytoplankton exudates at the sea surface and cloud formation in the Arctic (Engel et al. 2017), suggesting that impacts of films on phytoplankton could have far-reaching effects.
  • Possible toxic effects on organisms if surfactants are used (Robock 2011).

• Co-benefits
  • Unknown
• Risks
  • Unknown impacts on phytoplankton and primary production (Robock 2011, Seitz 2011). Deployment in low productivity waters may decrease risks (Gabriel et al. 2017).

• Co-benefits
  • Unknown
  • Potential opportunity to leverage technologies increasing fuel efficiency of ships contributing to decarbonization.
• Risks
  • If surfactants are toxic and impact organisms, there could be toxic effects when consumed by humans.

• Production of microbubbles could be terminated within days (Seitz 2011). However, if a surfactant were used, time would be needed to clean up the surfactant if that were even possible.

• Modeling study shows return to background temperatures when bubbles are stopped in about 5 years (Gabriel et al. 2017).
• Sea ice extent quickly reversed to match the sea ice extent of the default simulation in modeling study of the Arctic Ocean (Mengis et al. 2016).
• If foams are deployed with surfactants to increase the lifetime of foams, the return to lower albedo will depend on the lifetime of the foam. Foam lifetimes of tested foams are up to months long (Aziz et al. 2014).

• Co-benefits
  • Potential for delayed permafrost thaw (Mengis et al. 2016)
  • Potential for increased rainfall over land (Gabriel et al. 2017)
    • Could complement SAI because SAI may weaken hydrological cycle
  • Bubbles in ocean may launch seasalt aerosols that would also increase reflectivity of clouds (Evans et al. 2010, Crook et al. 2016)
  • A cooler ocean could make the ocean a more effective CO₂ sink (Robock 2011).
  • No risk to the ozone in the stratosphere, as compared with Stratospheric Aerosol Injection (Gabriel et al. 2017).
• Risks
  • Potential to impact ocean biogeochemistry with unknown consequences (Seitz 2011).
  • Potential to change impact vertical mixing in the ocean and alter ocean circulation (Robock 2011).
  • Bubbles and foam may change light availability (Robock 2011)
  • Unknown impacts on ocean circulation and evaporation which would impact atmospheric heating and circulation (Robock 2011)
  • Surfactants inhibit gas exchange at the ocean surface (Engel et al. 2017)
  • Subsurface warming in the Arctic from ocean albedo modification could potentially increase the risk of melting methane hydrates (Mengis et al. 2016).

• Co-benefits
  • Unknown
• Risks
  • Unknown effects on phytoplankton (Seitz 2011). Links have been shown between phytoplankton exudates at the sea surface and cloud formation in the Arctic (Engel et al. 2017), suggesting that impacts of films on phytoplankton could have far-reaching effects.
  • Possible toxic effects on organisms if surfactants are used (Robock 2011)

• Co-benefits
  • Unknown
• Risks
  • Unknown impacts on phytoplankton and primary production (Robock 2011, Seitz 2011). Deployment in low productivity waters may decrease risks (Gabriel et al. 2017).

• Co-benefits
  • Unknown
  • Potential opportunity to leverage technologies increasing fuel efficiency of ships contributing to decarbonization.
• Risks
  • If surfactants are toxic and impact organisms, there could be toxic effects when consumed by humans

• Production of microbubbles could be terminated within days (Seitz 2011). However, if a surfactant were used, time would be needed to clean up the surfactant if that were even possible.

• Modeling study shows return to background temperatures when bubbles are stopped in about 5 years (Gabriel et al. 2017).
• Sea ice extent quickly reversed to match the sea ice extent of the default simulation in modeling study of the Arctic Ocean (Mengis et al. 2016)
• If foams are deployed with surfactants to increase the lifetime of foams, the return to lower albedo will depend on the lifetime of the foam. Foam lifetimes of tested foams are up to months long (Aziz et al. 2014).

• Co-benefits
  • Potential for delayed permafrost thaw (Mengis et al. 2016)
  • Potential for increased rainfall over land (Gabriel et al. 2017)
    • Could complement SAI because SAI may weaken hydrological cycle
  • Bubbles in ocean may launch seasalt aerosols that would also increase reflectivity of clouds (Evans et al. 2010, Crook et al. 2016)
  • A cooler ocean could make the ocean a more effective CO₂ sink (Robock 2011).
  • No risk to the ozone in the stratosphere, as compared with Stratospheric Aerosol Injection (Gabriel et al. 2017).
• Risks
  • Potential to impact ocean biogeochemistry with unknown consequences (Seitz 2011).
  • Potential to change impact vertical mixing in the ocean and alter ocean circulation (Robock 2011).
  • Bubbles and foam may change light availability (Robock 2011)
  • Unknown impacts on ocean circulation and evaporation which would impact atmospheric heating and circulation (Robock 2011)
  • Surfactants inhibit gas exchange at the ocean surface (Engel et al. 2017)
  • Subsurface warming in the Arctic from ocean albedo modification could potentially increase the risk of melting methane hydrates (Mengis et al. 2016).

• Co-benefits
  • Unknown
• Risks
  • Unknown effects on phytoplankton (Seitz 2011). Links have been shown between phytoplankton exudates at the sea surface and cloud formation in the Artic (Engel et al. 2017), suggesting that impacts of films on phytoplankton could have far-reaching effects.
  • Possible toxic effects on organisms if surfactants are used (Robock 2011)

• Co-benefits
  • Unknown
• Risks
  • Unknown impacts on phytoplankton and primary production (Robock 2011, Seitz 2011). Deployment in low productivity waters may decrease risks (Gabriel et al. 2017).

• Co-benefits
  • Unknown
  • Potential opportunity to leverage technologies increasing fuel efficiency of ships contributing to decarbonization.
• Risks
  • If surfactants are toxic and impact organisms, there could be toxic effects when consumed by humans

• Production of microbubbles could be terminated within days (Seitz 2011). However, if a surfactant were used, time would be needed to clean up the surfactant if that were even possible.

• Modeling study shows return to background temperatures when bubbles are stopped in about 5 years (Gabriel et al. 2017).
• Sea ice extent quickly reversed to match the sea ice extent of the default simulation in modeling study of the Arctic Ocean (Mengis et al. 2016)
• If foams are deployed with surfactants to increase the lifetime of foams, the return to lower albedo will depend on the lifetime of the foam. Foam lifetimes of tested foams are up to months long (Aziz et al. 2014).

• Applicable to all approaches within Surface Albedo Modification:
  • Application of any approach in national waters (within territorial waters or a state’s exclusive economic zone (EEZ)) would be governed by those states. Small-scale field studies would likely be within national jurisdiction. However, even if applied with national jurisdiction there may be potential for transboundary effects due to dispersal of materials. Any application on the high seas would be within international jurisdiction. See “Existing governance” for other available information on relevant governance structures.
• Specific to Sea Foams or Films:
  • No additional information.

• Applicable to all approaches within Surface Albedo Modification:
  • 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).
  • For an Arctic-specific application, 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).
  • These approaches may be subject to regulation by the London Protocol as a type of solar radiation modification (C2G 2021 Evidence Brief CAT Arctic). Article 6 prohibits the placement of matter into the sea for marine geoengineering activities and to date has been used to regulate ocean iron fertilization.  The London Protocol only applies to the currently 55 parties to the Protocol, which includes Arctic coastal states except the United States and Russia.
  • 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). However, the current geopolitical landscape and lack of participation from Russia makes consensus difficult.
• Specific to Sea Foams or Films:
  • It is not clear yet as to whether sea foam or films would be considered a harmful substance and will depend on the surfactants or other material chosen.

• 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 Surface Albedo Modification:
    • 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 Sea Foams or Films:
    • No additional information.
• Procedural justice
  • Applicable to all approaches within Surface Albedo Modification:
    • 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 Sea Foams or Films:
    • No additional information.
• Restorative justice
  • Applicable to all approaches within Surface Albedo Modification:
    • It is unknown if there have been restorative justice actions for any Surface Albedo Modification approaches. 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 Sea Foams or Films:
    • No additional information.

• Unknown

• Applicable to all approaches within Surface Albedo Modification:
  • 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 Sea Foams or Films:
  • No additional information.

• Applicable to all approaches within Surface Albedo Modification:
  • Application of any approach in national waters (within territorial waters or a state’s exclusive economic zone (EEZ)) would be governed by those states. Small-scale field studies would likely be within national jurisdiction. However, even if applied with national jurisdiction there may be potential for transboundary effects due to dispersal of materials. Any application on the high seas would be within international jurisdiction. See “Existing governance” for other available information on relevant governance structures.
• Specific to Sea Foams or Films:
  • No additional information.

• Applicable to all approaches within Surface Albedo Modification:
  • 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).
  • For an Arctic-specific application, 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).
  • These approaches may be subject to regulation by the London Protocol as a type of solar radiation modification (C2G 2021 Evidence Brief CAT Arctic). Article 6 prohibits the placement of matter into the sea for marine geoengineering activities and to date has been used to regulate ocean iron fertilization.  The London Protocol only applies to the currently 55 parties to the Protocol, which includes Arctic coastal states except the United States and Russia.
  • 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). However, the current geopolitical landscape and lack of participation from Russia makes consensus difficult.
• Specific to Sea Foams or Films:
  • It is not clear yet as to whether sea foam or films would be considered a harmful substance and will depend on the surfactants or other material chosen.

• 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 Surface Albedo Modification:
    • 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 Sea Foams or Films:
    • No additional information.
• Procedural justice
  • Applicable to all approaches within Surface Albedo Modification:
    • 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 Sea Foams or Films:
    • No additional information.
• Restorative justice
  • Applicable to all approaches within Surface Albedo Modification:
    • It is unknown if there have been restorative justice actions for any Surface Albedo Modification approaches. 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 Sea Foams or Films:
    • No additional information.

• Unknown

• Applicable to all approaches within Surface Albedo Modification:
  • 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 Sea Foams or Films:
  • No additional information.

• Applicable to all approaches within Surface Albedo Modification:
  • Application of any approach in national waters (within territorial waters or a state’s exclusive economic zone (EEZ)) would be governed by those states. Small-scale field studies would likely be within national jurisdiction. However, even if applied with national jurisdiction there may be potential for transboundary effects due to dispersal of materials. Any application on the high seas would be within international jurisdiction. See “Existing governance” for other available information on relevant governance structures.
• Specific to Sea Foams or Films:
  • No additional information.

• Applicable to all approaches within Surface Albedo Modification:
  • 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).
  • For an Arctic-specific application, 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).
  • These approaches may be subject to regulation by the London Protocol as a type of solar radiation modification (C2G 2021 Evidence Brief CAT Arctic). Article 6 prohibits the placement of matter into the sea for marine geoengineering activities and to date has been used to regulate ocean iron fertilization.  The London Protocol only applies to the currently 55 parties to the Protocol, which includes Arctic coastal states except the United States and Russia.
  • 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). However, the current geopolitical landscape and lack of participation from Russia makes consensus difficult.
• Specific to Sea Foams or Films:
  • It is not clear yet as to whether sea foam or films would be considered a harmful substance and will depend on the surfactants or other material chosen.

• Distributive justice
  • Applicable to all approaches within Surface Albedo Modification:
    • 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 Sea Foams or Films:
    • No additional information.
• Procedural justice
  • Applicable to all approaches within Surface Albedo Modification:
    • 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 Sea Foams or Films:
    • No additional information.
• Restorative justice
  • Applicable to all approaches within Surface Albedo Modification:
    • It is unknown if there have been restorative justice actions for any Surface Albedo Modification approaches. 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 Sea Foams or Films:
    • No additional information.

• Unknown

• Applicable to all approaches within Surface Albedo Modification:
  • 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 Sea Foams or Films:
  • No additional information.

• Applicable to all approaches within Surface Albedo Modification:
  • Application of any approach in national waters (within territorial waters or a state’s exclusive economic zone (EEZ)) would be governed by those states. Small-scale field studies would likely be within national jurisdiction. However, even if applied with national jurisdiction there may be potential for transboundary effects due to dispersal of materials. Any application on the high seas would be within international jurisdiction. See “Existing governance” for other available information on relevant governance structures.
• Specific to Sea Foams or Films:
  • No additional information.

• Applicable to all approaches within Surface Albedo Modification:
  • 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).
  • For an Arctic-specific application, 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).
  • These approaches may be subject to regulation by the London Protocol as a type of solar radiation modification (C2G 2021 Evidence Brief CAT Arctic). Article 6 prohibits the placement of matter into the sea for marine geoengineering activities and to date has been used to regulate ocean iron fertilization.  The London Protocol only applies to the currently 55 parties to the Protocol, which includes Arctic coastal states except the United States and Russia.
  • 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). However, the current geopolitical landscape and lack of participation from Russia makes consensus difficult.
• Specific to Sea Foams or Films:
  • It is not clear yet as to whether sea foam or films would be considered a harmful substance and will depend on the surfactants or other material chosen.

• Distributive justice
  • Applicable to all approaches within Surface Albedo Modification:
    • 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 Sea Foams or Films:
    • No additional information.
• Procedural justice
  • Applicable to all approaches within Surface Albedo Modification:
    • 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 Sea Foams or Films:
    • No additional information.
• Restorative justice
  • Applicable to all approaches within Surface Albedo Modification:
    • It is unknown if there have been restorative justice actions for any Surface Albedo Modification approaches. 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 Sea Foams or Films:
    • No additional information.

• Unknown

• Applicable to all approaches within Surface Albedo Modification:
  • 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 Sea Foams or Films:
  • No additional information.

• Applicable to all approaches within Surface Albedo Modification:
  • Application of any approach in national waters (within territorial waters or a state’s exclusive economic zone (EEZ)) would be governed by those states. Small-scale field studies would likely be within national jurisdiction. However, even if applied with national jurisdiction there may be potential for transboundary effects due to dispersal of materials. Any application on the high seas would be within international jurisdiction. See “Existing governance” for other available information on relevant governance structures.
• Specific to Sea Foams or Films:
  • No additional information.

• Applicable to all approaches within Surface Albedo Modification:
  • 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).
  • For an Arctic-specific application, 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).
  • These approaches may be subject to regulation by the London Protocol as a type of solar radiation modification (C2G 2021 Evidence Brief CAT Arctic). Article 6 prohibits the placement of matter into the sea for marine geoengineering activities and to date has been used to regulate ocean iron fertilization.  The London Protocol only applies to the currently 55 parties to the Protocol, which includes Arctic coastal states except the United States and Russia.
  • 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). However, the current geopolitical landscape and lack of participation from Russia makes consensus difficult.
• Specific to Sea Foams or Films:
  • It is not clear yet as to whether sea foam or films would be considered a harmful substance and will depend on the surfactants or other material chosen.

• Distributive justice
  • Applicable to all approaches within Surface Albedo Modification:
    • 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 Sea Foams or Films:
    • No additional information.
• Procedural justice
  • Applicable to all approaches within Surface Albedo Modification:
    • 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 Sea Foams or Films:
    • No additional information.
• Restorative justice
  • Applicable to all approaches within Surface Albedo Modification:
    • It is unknown if there have been restorative justice actions for any Surface Albedo Modification approaches. 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 Sea Foams or Films:
    • No additional information.

• Unknown

• Applicable to all approaches within Surface Albedo Modification:
  • 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 Sea Foams or Films:
  • No additional information.