• Decreasing the use of CO₂ emitting technologies (e.g., burning fossil fuels) or replacing CO₂ emitting technologies or processes with low or zero emissions energy technologies or processes (e.g., renewable energy). Examples of emissions reductions technologies include decarbonizing energy services such as heating, cooling, and lighting via electricity generation from renewable energy sources (e.g., solar and wind). Other energy services such as aviation, long-distance transportation, and shipping, as well as the production of materials like steel and cement are more difficult to decarbonize (Davis et al. 2018, DeAngelo et al. 2021). However, research into and development of biofuels, electrofuels (Cabrera and de Sousa 2022), and alternative building materials (Sbahieh et al. 2023) continues. Increasing the capacity of renewable energy is the largest driver of emissions reductions to reach net zero by 2050, followed by energy intensity improvements (increasing efficiency) and electrification of end-uses such as electric vehicles and heat pumps (IEA 2023).
  • The International Energy Agency’s Net Zero Roadmap provides detailed information about decarbonization pathways and needs. This most recent version of the roadmap (2023) includes deep dives into 15 technologies and sectors.
• Decreasing consumption in general has also been shown to reduce CO₂ emissions (Khanna et al. 2021).

• These technologies either emit zero carbon emissions or lower carbon emissions than that of which they are replacing. For instance, utilizing renewable energy instead of gas results in lower net carbon dioxide emissions. By implementing these technologies, CO₂ emissions will decrease, thereby slowing or ceasing increases in global mean surface temperature.

• Varies depending on the particular technology
  • Increasing solar and wind energy generation have limitations based on site suitability and available area.
    • Large land areas are needed for renewable energy – greater than 4 times what is currently in use today (utility-scale solar PV and onshore wind in operation in 2022 estimated to cover <0.2 million km²) by 2030 and greater than 10 times what is currently in use today by 2050 (20 million km²; IEA 2023). About one third of global land is unsuitable for solar and wind energy installations (IEA 2023).

• Typically on the surface and on land, but biofuels or other alternative aviation fuels would be used during air travel (troposphere and stratosphere). Switching to alternative fuels for shipping, or offshore wind farms would occur in the ocean.

• Currently Arctic, regional, and global. Most applications are not specifically targeting the Arctic but rather aimed at keeping the global temperature rise below 1.5 or 2.0 degrees Celsius, as per the Paris Agreement. Some technologies, such as solar or wind, may be less effective in the Arctic due to limited sunlight or extreme cold.

• Varies depending on the technology. Renewable energy that depends on a seasonal energy source (e.g., solar) maybe be more effective in certain months of the year. Other technologies like biofuels would be effective all year.

• Decreasing the use of CO₂ emitting technologies (e.g., burning fossil fuels) or replacing CO₂ emitting technologies or processes with low or zero emissions energy technologies or processes (e.g., renewable energy). Examples of emissions reductions technologies include decarbonizing energy services such as heating, cooling, and lighting via electricity generation from renewable energy sources (e.g., solar and wind). Other energy services such as aviation, long-distance transportation, and shipping, as well as the production of materials like steel and cement are more difficult to decarbonize (Davis et al. 2018, DeAngelo et al. 2021). However, research into and development of biofuels, electrofuels (Cabrera and de Sousa 2022), and alternative building materials (Sbahieh et al. 2023) continues. Increasing the capacity of renewable energy is the largest driver of emissions reductions to reach net zero by 2050, followed by energy intensity improvements (increasing efficiency) and electrification of end-uses such as electric vehicles and heat pumps (IEA 2023).
  • The International Energy Agency’s Net Zero Roadmap provides detailed information about decarbonization pathways and needs. This most recent version of the roadmap (2023) includes deep dives into 15 technologies and sectors.
• Decreasing consumption in general has also been shown to reduce CO₂ emissions (Khanna et al. 2021).

• These technologies either emit zero carbon emissions or lower carbon emissions than that of which they are replacing. For instance, utilizing renewable energy instead of gas results in lower net carbon dioxide emissions. By implementing these technologies, CO₂ emissions will decrease, thereby slowing or ceasing increases in global mean surface temperature.

• Varies depending on the particular technology
  • Increasing solar and wind energy generation have limitations based on site suitability and available area
    • Large land areas are needed for renewable energy – greater than 4 times what is currently in use today (utility-scale solar PV and onshore wind in operation in 2022 estimated to cover <0.2 million km²) by 2030 and greater than 10 times what is currently in use today by 2050 (20 million km²; IEA 2023). About one third of global land is unsuitable for solar and wind energy installations (IEA 2023).

• Typically on the surface and on land, but biofuels or other alternative aviation fuels would be used during air travel (troposphere and stratosphere). Switching to alternative fuels for shipping, or offshore wind farms would occur in the ocean.

• Currently Arctic, regional, and global. Most applications are not specifically targeting the Arctic but rather aimed at keeping the global temperature rise below 1.5 or 2.0 degrees Celsius, as per the Paris Agreement. Some technologies, such as solar or wind, may be less effective in the Arctic due to limited sunlight or extreme cold.

• Varies depending on the technology. Renewable energy that depends on a seasonal energy source (e.g., solar) maybe be more effective in certain months of the year. Other technologies like biofuels would be effective all year.

• Decreasing the use of CO₂ emitting technologies (e.g., burning fossil fuels) or replacing CO₂ emitting technologies or processes with low or zero emissions energy technologies or processes (e.g., renewable energy). Examples of emissions reductions technologies include decarbonizing energy services such as heating, cooling, and lighting via electricity generation from renewable energy sources (e.g., solar and wind). Other energy services such as aviation, long-distance transportation, and shipping, as well as the production of materials like steel and cement are more difficult to decarbonize (Davis et al. 2018, DeAngelo et al. 2021). However, research into and development of biofuels, electrofuels (Cabrera and de Sousa 2022), and alternative building materials (Sbahieh et al. 2023) continues. Increasing the capacity of renewable energy is the largest driver of emissions reductions to reach net zero by 2050, followed by energy intensity improvements (increasing efficiency) and electrification of end-uses such as electric vehicles and heat pumps (IEA 2023).
  • The International Energy Agency’s Net Zero Roadmap provides detailed information about decarbonization pathways and needs. This most recent version of the roadmap (2023) includes deep dives into 15 technologies and sectors.
• Decreasing consumption in general has also been shown to reduce CO₂ emissions (Khanna et al. 2021).

• These technologies either emit zero carbon emissions or lower carbon emissions than that of which they are replacing. For instance, utilizing renewable energy instead of gas results in lower net carbon dioxide emissions. By implementing these technologies, CO₂ emissions will decrease, thereby slowing or ceasing increases in global mean surface temperature.

• Varies depending on the particular technology
  • Increasing solar and wind energy generation have limitations based on site suitability and available area
    • Large land areas are needed for renewable energy – greater than 4 times what is currently in use today (utility-scale solar PV and onshore wind in operation in 2022 estimated to cover <0.2 million km²) by 2030 and greater than 10 times what is currently in use today by 2050 (20 million km²; IEA 2023). About one third of global land is unsuitable for solar and wind energy installations (IEA 2023).

• Typically on the surface and on land, but biofuels or other alternative aviation fuels would be used during air travel (troposphere and stratosphere). Switching to alternative fuels for shipping, or offshore wind farms would occur in the ocean.

• Currently Arctic, regional, and global. Most applications are not specifically targeting the Arctic but rather aimed at keeping the global temperature rise below 1.5 or 2.0 degrees Celsius, as per the Paris Agreement. Some technologies, such as solar or wind, may be less effective in the Arctic due to limited sunlight or extreme cold.

• Varies depending on the technology. Renewable energy that depends on a seasonal energy source (e.g., solar) maybe be more effective in certain months of the year. Other technologies like biofuels would be effective all year.

• Decreasing the use of CO₂ emitting technologies (e.g., burning fossil fuels) or replacing CO₂ emitting technologies or processes with low or zero emissions energy technologies or processes (e.g., renewable energy). Examples of emissions reductions technologies include decarbonizing energy services such as heating, cooling, and lighting via electricity generation from renewable energy sources (e.g., solar and wind). Other energy services such as aviation, long-distance transportation, and shipping, as well as the production of materials like steel and cement are more difficult to decarbonize (Davis et al. 2018, DeAngelo et al. 2021). However, research into and development of biofuels, electrofuels (Cabrera and de Sousa 2022), and alternative building materials (Sbahieh et al. 2023) continues. Increasing the capacity of renewable energy is the largest driver of emissions reductions to reach net zero by 2050, followed by energy intensity improvements (increasing efficiency) and electrification of end-uses such as electric vehicles and heat pumps (IEA 2023).
  • The International Energy Agency’s Net Zero Roadmap provides detailed information about decarbonization pathways and needs. This most recent version of the roadmap (2023) includes deep dives into 15 technologies and sectors.
• Decreasing consumption in general has also been shown to reduce CO₂ emissions (Khanna et al. 2021).

• These technologies either emit zero carbon emissions or lower carbon emissions than that of which they are replacing. For instance, utilizing renewable energy instead of gas results in lower net carbon dioxide emissions. By implementing these technologies, CO₂ emissions will decrease, thereby slowing or ceasing increases in global mean surface temperature.

• Varies depending on the particular technology
  • Increasing solar and wind energy generation have limitations based on site suitability and available area
    • Large land areas are needed for renewable energy – greater than 4 times what is currently in use today (utility-scale solar PV and onshore wind in operation in 2022 estimated to cover <0.2 million km²) by 2030 and greater than 10 times what is currently in use today by 2050 (20 million km²; IEA 2023). About one third of global land is unsuitable for solar and wind energy installations (IEA 2023).

• Typically on the surface and on land, but biofuels or other alternative aviation fuels would be used during air travel (troposphere and stratosphere). Switching to alternative fuels for shipping, or offshore wind farms would occur in the ocean.

• Currently Arctic, regional, and global. Most applications are not specifically targeting the Arctic but rather aimed at keeping the global temperature rise below 1.5 or 2.0 degrees Celsius, as per the Paris Agreement. Some technologies, such as solar or wind, may be less effective in the Arctic due to limited sunlight or extreme cold.

• Varies depending on the technology. Renewable energy that depends on a seasonal energy source (e.g., solar) maybe be more effective in certain months of the year. Other technologies like biofuels would be effective all year.

Impact on

• Variable predictions
  • All emissions reduction scenarios predict ice-free conditions in the Arctic during September by 2050 (reviewed in Jahn et al. 2024), which would decrease albedo in the Arctic region.

• Global
  • Decreases of 0.1°C up to 1.6°C by 2100 as compared to business as usual emissions trajectories
    • Decrease of 0.1°C by 2050 and up to 1.6°C by 2100 (not accounting for extra warming that may occur from unmasking cooling from aerosol pollution) if CO₂ emissions peak in 2030 and carbon neutrality reached 2060-2070 (Xu and Ramanathan 2017 in Zaelke et al. 2023).
    • Decarbonization alone will breach 2.0°C by 2045, even more aggressive mitigation scenarios proposed by the IPCC (Dreyfus et al. 2022). This impact is partly due to unmasking the cooling effect of co-emitted aerosols (Dreyfus et al. 2022).
    • Implementing unconditional Nationally Determined Contributions (NDCs) made under the Paris Agreement would decrease temperatures by approximately 0.5°C compared to current policies continuing, however this corresponds to a mean global temperature of approximately 2.9°C above pre-industrial temperatures (UNEP 2023).
    • The NZE Scenario with rapid emissions cuts in the Net Zero Roadmap by the International Energy Association (2023) keeps overall warming below 1.5°C by 2100 with low overshoot as defined by the IPCC. Note that this scenario also includes methane emissions reductions.
• Arctic region
  • Decreases of 6°C by 2100 compared to trajectory with no emissions reduction and mitigation
    • Compared to no emissions reductions and mitigation, Arctic temperatures would decrease 6°C by 2100 with emissions reductions. However, the mean Arctic temperature would still be 7°C higher compared to baseline temperatures (Williams 2021).
    • Estimate of Arctic region temperature impact by 2050 is decreased of 1-2.5°C compared to no emissions reductions and mitigation (Overland et al. 2013, Overland et al. 2019).

• Global
  • Unknown
    • Most references of radiative forcing change are reported for total GHGs and not due to CO₂ emissions reductions alone.
    • Estimates provided in Dreyfus et al. (2022) are in °C, not in radiative forcing units.
• Arctic region
  • Unknown

• Direct or indirect impact on sea ice?
  • Indirect
• New or old ice?
  • Both
• Impact on sea ice
  • All emissions scenarios predict ice-free conditions in the Arctic in September by 2050 (reviewed in Jahn et al. 2024).
  • If emissions reductions limit warming to < 1.5°C there is <10% chance that the Arctic would not become ice free (Jahn et al. 2024).
  • With emissions reductions consistent with Shared Socioeconomic Pathway (SSP)1-1.9, consistently ice-free conditions would be limited to September (Jahn et al. 2024).
  • As emissions reductions increase and temperatures decrease, sea ice has the ability to come back even if ice-free conditions appear (Jahn et al. 2024).

Scalability

• Depends on technology and region
  • For renewable energy, scalability is limited by site suitability and conflicts with other uses.
  • For renewable energy, advanced economies are on track to achieve contributions to global goals, however, policies and international support are needed to advance progress of developing economies (IEA 2023).

• Depends on technology

• Unknown
  • While many technologies are already technically feasible, permitting, infrastructure development, supply chain issues, and integration of renewable energy sources are current barriers to scalability (IEA 2023).

• Possible, but unlikely. Substantial and rapid emissions reductions are needed with CO₂ emissions peaking by or before 2030 and net zero achieved in the following decades (Xu and Ramanathan 2017, IEA 2023). Projected emissions trajectories imply that warming will exceed 1.5°C (IPCC 2022).

• Likely > 20 years. All emissions scenarios predict ice-free conditions in the Arctic in September by 2050 (reviewed in Jahn et al. 2024). As emissions reductions increase over time and temperatures further decrease, sea ice does have the ability to rebound (Jahn et al. 2024).

Cost

• $4.5 trillion USD/year needed to invest in clean energy by the early 2030s (IEA 2023).
• An overview of emissions reductions options with estimated costs and potentials is available in IPCC ARG Working Group 3 report.
• In addition to the economic cost to decarbonize, there is also a cost associated with the lack of appropriate decarbonization. This is represented by the social cost of carbon (SCC), which estimates the economic damage resulting from emissions per ton of carbon dioxide. A 2022 study by Rennert et al. recommended that the SCC be set to $185/tCO₂. The SCC is currently set at $190/tCO₂ for the United States Government.

• Unknown

Impact on

• Variable predictions
  • All emissions reduction scenarios predict ice-free conditions in the Arctic during September by 2050 (reviewed in Jahn et al. 2024), which would decrease albedo in the Arctic region.

• Global
  • Decreases of 0.1°C up to 1.6°C by 2100 as compared to business as usual emissions trajectories
    • Decrease of 0.1°C by 2050 and up to 1.6°C by 2100 (not accounting for extra warming that may occur from unmasking cooling from aerosol pollution) if CO₂ emissions peak in 2030 and carbon neutrality reached 2060-2070 (Xu and Ramanathan 2017 in Zaelke et al. 2023).
    • Decarbonization alone will breach 2.0°C by 2045, even more aggressive mitigation scenarios proposed by the IPCC (Dreyfus et al. 2022). This impact is partly due to unmasking the cooling effect of co-emitted aerosols (Dreyfus et al. 2022).
    • Implementing unconditional Nationally Determined Contributions (NDCs) made under the Paris Agreement would decrease temperatures by approximately 0.5°C compared to current policies continuing, however this corresponds to a mean global temperature of approximately 2.9°C above pre-industrial temperatures (UNEP 2023).
    • The NZE Scenario with rapid emissions cuts in the Net Zero Roadmap by the International Energy Association (2023) keeps overall warming below 1.5°C by 2100 with low overshoot as defined by the IPCC. Note that this scenario also includes methane emissions reductions.
• Arctic region
  • Decreases of 6°C by 2100 compared to trajectory with no emissions reduction and mitigation
    • Compared to no emissions reductions and mitigation, Arctic temperatures would decrease 6°C by 2100 with emissions reductions. However, the mean Arctic temperature would still be 7°C higher compared to baseline temperatures (Williams 2021).
    • Estimate of Arctic region temperature impact by 2050 is decreased of 1-2.5°C compared to no emissions reductions and mitigation (Overland et al. 2013, Overland et al. 2019).

• Global
  • Unknown
    • Most references of radiative forcing change are reported for total GHGs and not due to CO₂ emissions reductions alone
    • Estimates provided in Dreyfus et al. (2022) are in °C, not in radiative forcing units.
• Arctic region
  • Unknown

• Direct or indirect impact on sea ice?
  • Indirect
• New or old ice?
  • Both
• Impact on sea ice
  • All emissions scenarios predict ice-free conditions in the Arctic in September by 2050 (reviewed in Jahn et al. 2024).
  • If emissions reductions limit warming to < 1.5°C there is <10% chance that the Arctic would not become ice free (Jahn et al. 2024).
  • With emissions reductions consistent with Shared Socioeconomic Pathway (SSP)1-1.9, consistently ice-free conditions would be limited to September (Jahn et al. 2024).
  • As emissions reductions increase and temperatures decrease, sea ice has the ability to come back even if ice-free conditions appear (Jahn et al. 2024).

Scalability

• Depends on technology and region
  • For renewable energy, scalability is limited by site suitability and conflicts with other uses.
  • For renewable energy, advanced economies are on track to achieve contributions to global goals, however, policies and international support are needed to advance progress of developing economies (IEA 2023)

• Depends on technology

• Unknown
  • While many technologies are already technically feasible, permitting, infrastructure development, supply chain issues, and integration of renewable energy sources are current barriers to scalability (IEA 2023).

• Possible, but unlikely. Substantial and rapid emissions reductions are needed with CO₂ emissions peaking by or before 2030 and net zero achieved in the following decades (Xu and Ramanathan 2017, IEA 2023). Projected emissions trajectories imply that warming will exceed 1.5°C (IPCC 2022).

• Likely > 20 years. All emissions scenarios predict ice-free conditions in the Arctic in September by 2050 (reviewed in Jahn et al. 2024). As emissions reductions increase over time and temperatures further decrease, sea ice does have the ability to rebound (Jahn et al. 2024).

Cost

• $4.5 trillion USD/year needed to invest in clean energy by the early 2030s (IEA 2023).
• An overview of emissions reductions options with estimated costs and potentials is available in IPCC ARG Working Group 3 report.
• In addition to the economic cost to decarbonize, there is also a cost associated with the lack of appropriate decarbonization. This is represented by the social cost of carbon (SCC), which estimates the economic damage resulting from emissions per ton of carbon dioxide. A 2022 study by Rennert et al. recommended that the SCC be set to $185/tCO₂. The SCC is currently set at $190/tCO₂ for the United States Government.

• Unknown

Impact on

• Variable predictions
  • All emissions reduction scenarios predict ice-free conditions in the Arctic during September by 2050 (reviewed in Jahn et al. 2024), which would decrease albedo in the Arctic region.

• Global
  • Decreases of 0.1°C up to 1.6°C by 2100 as compared to business as usual emissions trajectories
    • Decrease of 0.1°C by 2050 and up to 1.6°C by 2100 (not accounting for extra warming that may occur from unmasking cooling from aerosol pollution) if CO₂ emissions peak in 2030 and carbon neutrality reached 2060-2070 (Xu and Ramanathan 2017 in Zaelke et al. 2023).
    • Decarbonization alone will breach 2.0°C by 2045, even more aggressive mitigation scenarios proposed by the IPCC (Dreyfus et al. 2022). This impact is partly due to unmasking the cooling effect of co-emitted aerosols (Dreyfus et al. 2022).
    • Implementing unconditional Nationally Determined Contributions (NDCs) made under the Paris Agreement would decrease temperatures by approximately 0.5°C compared to current policies continuing, however this corresponds to a mean global temperature of approximately 2.9°C above pre-industrial temperatures (UNEP 2023).
    • The NZE Scenario with rapid emissions cuts in the Net Zero Roadmap by the International Energy Association (2023) keeps overall warming below 1.5°C by 2100 with low overshoot as defined by the IPCC. Note that this scenario also includes methane emissions reductions.
• Arctic region
  • Decreases of 6°C by 2100 compared to trajectory with no emissions reduction and mitigation
    • Compared to no emissions reductions and mitigation, Arctic temperatures would decrease 6°C by 2100 with emissions reductions. However, the mean Arctic temperature would still be 7°C higher compared to baseline temperatures (Williams 2021).
    • Estimate of Arctic region temperature impact by 2050 is decreased of 1-2.5°C compared to no emissions reductions and mitigation (Overland et al. 2013, Overland et al. 2019).

• Global
  • Unknown
    • Most references of radiative forcing change are reported for total GHGs and not due to CO₂ emissions reductions alone
    • Estimates provided in Dreyfus et al. (2022) are in °C, not in radiative forcing units.
• Arctic region
  • Unknown

• Direct or indirect impact on sea ice?
  • Indirect
• New or old ice?
  • Both
• Impact on sea ice
  • All emissions scenarios predict ice-free conditions in the Arctic in September by 2050 (reviewed in Jahn et al. 2024).
  • If emissions reductions limit warming to < 1.5°C there is <10% chance that the Arctic would not become ice free (Jahn et al. 2024).
  • With emissions reductions consistent with Shared Socioeconomic Pathway (SSP)1-1.9, consistently ice-free conditions would be limited to September (Jahn et al. 2024).
  • As emissions reductions increase and temperatures decrease, sea ice has the ability to come back even if ice-free conditions appear (Jahn et al. 2024).

Scalability

• Depends on technology and region
  • For renewable energy, scalability is limited by site suitability and conflicts with other uses.
  • For renewable energy, advanced economies are on track to achieve contributions to global goals, however, policies and international support are needed to advance progress of developing economies (IEA 2023)

• Depends on technology

• Unknown
  • While many technologies are already technically feasible, permitting, infrastructure development, supply chain issues, and integration of renewable energy sources are current barriers to scalability (IEA 2023).

• Possible, but unlikely. Substantial and rapid emissions reductions are needed with CO₂ emissions peaking by or before 2030 and net zero achieved in the following decades (Xu and Ramanathan 2017, IEA 2023). Projected emissions trajectories imply that warming will exceed 1.5°C (IPCC 2022).

• Likely > 20 years. All emissions scenarios predict ice-free conditions in the Arctic in September by 2050 (reviewed in Jahn et al. 2024). As emissions reductions increase over time and temperatures further decrease, sea ice does have the ability to rebound (Jahn et al. 2024).

Cost

• $4.5 trillion USD/year needed to invest in clean energy by the early 2030s (IEA 2023).
• An overview of emissions reductions options with estimated costs and potentials is available in IPCC ARG Working Group 3 report.
• In addition to the economic cost to decarbonize, there is also a cost associated with the lack of appropriate decarbonization. This is represented by the social cost of carbon (SCC), which estimates the economic damage resulting from emissions per ton of carbon dioxide. A 2022 study by Rennert et al. recommended that the SCC be set to $185/tCO₂. The SCC is currently set at $190/tCO₂ for the United States Government.

• Unknown

Impact on

• Variable predictions
  • All emissions reduction scenarios predict ice-free conditions in the Arctic during September by 2050 (reviewed in Jahn et al. 2024), which would decrease albedo in the Arctic region.

• Global
  • Decreases of 0.1°C up to 1.6°C by 2100 as compared to business as usual emissions trajectories
    • Decrease of 0.1°C by 2050 and up to 1.6°C by 2100 (not accounting for extra warming that may occur from unmasking cooling from aerosol pollution) if CO₂ emissions peak in 2030 and carbon neutrality reached 2060-2070 (Xu and Ramanathan 2017 in Zaelke et al. 2023).
    • Decarbonization alone will breach 2.0°C by 2045, even more aggressive mitigation scenarios proposed by the IPCC (Dreyfus et al. 2022). This impact is partly due to unmasking the cooling effect of co-emitted aerosols (Dreyfus et al. 2022).
    • Implementing unconditional Nationally Determined Contributions (NDCs) made under the Paris Agreement would decrease temperatures by approximately 0.5°C compared to current policies continuing, however this corresponds to a mean global temperature of approximately 2.9°C above pre-industrial temperatures (UNEP 2023).
    • The NZE Scenario with rapid emissions cuts in the Net Zero Roadmap by the International Energy Association (2023) keeps overall warming below 1.5°C by 2100 with low overshoot as defined by the IPCC. Note that this scenario also includes methane emissions reductions.
• Arctic region
  • Decreases of 6°C by 2100
    • Compared to no emissions reductions and mitigation, Arctic temperatures would decrease 6°C by 2100 with emissions reductions. However, the mean Arctic temperature would still be 7°C higher compared to baseline temperatures (Williams 2021).

• Global
  • Unknown
    • Most references of radiative forcing change are reported for total GHGs and not due to CO₂ emissions reductions alone
    • Estimates provided in Dreyfus et al. (2022) are in °C, not in radiative forcing units.
• Arctic region
  • Unknown

• Direct or indirect impact on sea ice?
  • Indirect
• New or old ice?
  • Both
• Impact on sea ice
  • All emissions scenarios predict ice-free conditions in the Arctic in September by 2050 (reviewed in Jahn et al. 2024).
  • If emissions reductions limit warming to < 1.5°C there is <10% chance that the Arctic would not become ice free (Jahn et al. 2024).
  • With emissions reductions consistent with Shared Socioeconomic Pathway (SSP)1-1.9, consistently ice-free conditions would be limited to September (Jahn et al. 2024).
  • As emissions reductions increase and temperatures decrease, sea ice has the ability to come back even if ice-free conditions appear (Jahn et al. 2024).

Scalability

• Depends on technology and region
  • For renewable energy, scalability is limited by site suitability and conflicts with other uses.
  • For renewable energy, advanced economies are on track to achieve contributions to global goals, however, policies and international support are needed to advance progress of developing economies (IEA 2023)

• Depends on technology

• Unknown
  • While many technologies are already technically feasible, permitting, infrastructure development, supply chain issues, and integration of renewable energy sources are current barriers to scalability (IEA 2023).

• Possible, but unlikely. Substantial and rapid emissions reductions are needed with CO₂ emissions peaking by or before 2030 and net zero achieved in the following decades (Xu and Ramanathan 2017, IEA 2023). Projected emissions trajectories imply that warming will exceed 1.5°C (IPCC 2022).

• Likely > 20 years. All emissions scenarios predict ice-free conditions in the Arctic in September by 2050 (reviewed in Jahn et al. 2024). As emissions reductions increase over time and temperatures further decrease, sea ice does have the ability to rebound (Jahn et al. 2024).

Cost

• $4.5 trillion USD/year needed to invest in clean energy by the early 2030s (IEA 2023).
• An overview of emissions reductions options with estimated costs and potentials is available in IPCC ARG Working Group 3 report.
• In addition to the economic cost to decarbonize, there is also a cost associated with the lack of appropriate decarbonization. This is represented by the social cost of carbon (SCC), which estimates the economic damage resulting from emissions per ton of carbon dioxide. A 2022 study by Rennert et al. recommended that the SCC be set to $185/tCO₂. The SCC is currently set at $190/tCO₂ for the United States Government.

• Unknown

Impact on

• Variable predictions
  • All emissions reduction scenarios predict ice-free conditions in the Arctic during September by 2050 (reviewed in Jahn et al. 2024), which would decrease albedo in the Arctic region.

• Global
  • Decreases of 0.1°C up to 1.6°C by 2100
    • Decrease of 0.1°C by 2050 and up to 1.6°C by 2100 (not accounting for extra warming that may occur from unmasking cooling from aerosol pollution) if CO₂ emissions peak in 2030 and carbon neutrality reached 2060-2070 (Xu and Ramanathan 2017 in Zaelke et al. 2023).
    • Decarbonization alone will breach 2.0°C by 2045, even more aggressive mitigation scenarios proposed by the IPCC (Dreyfus et al. 2022). This impact is partly due to unmasking the cooling effect of co-emitted aerosols (Dreyfus et al. 2022).
    • Implementing unconditional Nationally Determined Contributions (NDCs) made under the Paris Agreement would decrease temperatures by approximately 0.5°C compared to current policies continuing, however this corresponds to a mean global temperature of approximately 2.9°C above pre-industrial temperatures (UNEP 2023).
    • The NZE Scenario with rapid emissions cuts in the Net Zero Roadmap by the International Energy Association (2023) keeps overall warming below 1.5°C by 2100 with low overshoot as defined by the IPCC. Note that this scenario also includes methane emissions reductions.
• Arctic region
  • Decreases of 6°C by 2100
    • Compared to no emissions reductions and mitigation, Arctic temperatures would decrease 6°C by 2100 with emissions reductions. However, the mean Arctic temperature would still be 7°C higher compared to baseline temperatures (Williams 2021).

• Global
  • Unknown
    • Most references of radiative forcing change are reported for total GHGs and not due to CO₂ emissions reductions alone
    • Estimates provided in Dreyfus et al. (2022) are in °C, not in radiative forcing units.
• Arctic region
  • Unknown

• Direct or indirect impact on sea ice?
  • Indirect
• New or old ice?
  • Both
• Impact on sea ice
  • All emissions scenarios predict ice-free conditions in the Arctic in September by 2050 (reviewed in Jahn et al. 2024).
  • If emissions reductions limit warming to < 1.5°C there is <10% chance that the Arctic would not become ice free (Jahn et al. 2024).
  • With emissions reductions consistent with Shared Socioeconomic Pathway (SSP)1-1.9, consistently ice-free conditions would be limited to September (Jahn et al. 2024).
  • As emissions reductions increase and temperatures decrease, sea ice has the ability to come back even if ice-free conditions appear (Jahn et al. 2024).

Scalability

• Depends on technology and region
  • For renewable energy, scalability is limited by site suitability and conflicts with other uses.
  • For renewable energy, advanced economies are on track to achieve contributions to global goals, however, policies and international support are needed to advance progress of developing economies (IEA 2023)

• Depends on technology

• Unknown
  • While many technologies are already technically feasible, permitting, infrastructure development, supply chain issues, and integration of renewable energy sources are current barriers to scalability (IEA 2023).

• Possible, but unlikely. Substantial and rapid emissions reductions are needed with CO₂ emissions peaking by or before 2030 and net zero achieved in the following decades (Xu and Ramanathan 2017, IEA 2023). Projected emissions trajectories imply that warming will exceed 1.5°C (IPCC 2022).

• Likely > 20 years. All emissions scenarios predict ice-free conditions in the Arctic in September by 2050 (reviewed in Jahn et al. 2024). As emissions reductions increase over time and temperatures further decrease, sea ice does have the ability to rebound (Jahn et al. 2024).

Cost

• $4.5 trillion USD/year needed to invest in clean energy by the early 2030s (IEA 2023).
• An overview of emissions reductions options with estimated costs and potentials is available in IPCC ARG Working Group 3 report.
• In addition to the economic cost to decarbonize, there is also a cost associated with the lack of appropriate decarbonization. This is represented by the social cost of carbon (SCC), which estimates the economic damage resulting from emissions per ton of carbon dioxide. A 2022 study by Rennert et al. recommended that the SCC be set to $185/tCO₂. The SCC is currently set at $190/tCO₂ for the United States Government.

• Unknown

Impact on

• Variable predictions
  • All emissions reduction scenarios predict ice-free conditions in the Arctic during September by 2050 (reviewed in Jahn et al. 2024), which would decrease albedo in the Arctic region.

• Global
  • Decreases of 0.1°C up to 1.6°C by 2100
    • Decrease of 0.1°C by 2050 and up to 1.6°C by 2100 (not accounting for extra warming that may occur from unmasking cooling from aerosol pollution) if CO₂ emissions peak in 2030 and carbon neutrality reached 2060-2070 (Xu and Ramanathan 2017 in Zaelke et al. 2023).
    • Decarbonization alone will breach 2.0°C by 2045, even more aggressive mitigation scenarios proposed by the IPCC (Dreyfus et al. 2022). This impact is partly due to unmasking the cooling effect of co-emitted aerosols (Dreyfus et al. 2022).
    • Implementing unconditional Nationally Determined Contributions (NDCs) made under the Paris Agreement would decrease temperatures by approximately 0.5°C compared to current policies continuing, however this corresponds to a mean global temperature of approximately 2.9°C above pre-industrial temperatures (UNEP 2023).
    • The NZE Scenario with rapid emissions cuts in the Net Zero Roadmap by the International Energy Association (2023) keeps overall warming below 1.5°C by 2100 with low overshoot as defined by the IPCC. Note that this scenario also includes methane emissions reductions.
• Arctic region
  • Decreases of 6°C by 2100
    • Compared to no emissions reductions and mitigation, Arctic temperatures would decrease 6°C by 2100 with emissions reductions. However, the mean Arctic temperature would still be 7°C higher compared to baseline temperatures (Williams 2021).

• Global
  • Unknown
    • Most references of radiative forcing change are reported for total GHGs and not due to CO₂ emissions reductions alone
    • Estimates provided in Dreyfus et al. (2022) are in °C, not in radiative forcing units.
  • Arctic region
    • Unknown

• Direct or indirect impact on sea ice?
  • Indirect
• New or old ice?
  • Both
• Impact on sea ice
  • All emissions scenarios predict ice-free conditions in the Arctic in September by 2050 (reviewed in Jahn et al. 2024).
  • If emissions reductions limit warming to < 1.5°C there is <10% chance that the Arctic would not become ice free (Jahn et al. 2024).
  • With emissions reductions consistent with Shared Socioeconomic Pathway (SSP)1-1.9, consistently ice-free conditions would be limited to September (Jahn et al. 2024).
  • As emissions reductions increase and temperatures decrease, sea ice has the ability to come back even if ice-free conditions appear (Jahn et al. 2024).

Scalability

• Depends on technology and region
  • For renewable energy, scalability is limited by site suitability and conflicts with other uses.
  • For renewable energy, advanced economies are on track to achieve contributions to global goals, however, policies and international support are needed to advance progress of developing economies (IEA 2023)

• Depends on technology

• Unknown
  • While many technologies are already technically feasible, permitting, infrastructure development, supply chain issues, and integration of renewable energy sources are current barriers to scalability (IEA 2023).

• Possible, but unlikely. Substantial and rapid emissions reductions are needed with CO₂ emissions peaking by or before 2030 and net zero achieved in the following decades (Xu and Ramanathan 2017, IEA 2023). Projected emissions trajectories imply that warming will exceed 1.5°C (IPCC 2022).

• Likely > 20 years. All emissions scenarios predict ice-free conditions in the Arctic in September by 2050 (reviewed in Jahn et al. 2024). As emissions reductions increase over time and temperatures further decrease, sea ice does have the ability to rebound (Jahn et al. 2024).

Cost

• $4.5 trillion USD/year needed to invest in clean energy by the early 2030s (IEA 2023).
• An overview of emissions reductions options with estimated costs and potentials is available in IPCC ARG Working Group 3 report.
• In addition to the economic cost to decarbonize, there is also a cost associated with the lack of appropriate decarbonization. This is represented by the social cost of carbon (SCC), which estimates the economic damage resulting from emissions per ton of carbon dioxide. A 2022 study by Rennert et al. recommended that the SCC be set to $185/tCO₂. The SCC is currently set at $190/tCO₂ for the United States Government.

• Unknown

Impact on

• Variable predictions
  • All emissions reduction scenarios predict ice-free conditions in the Arctic during September by 2050 (reviewed in Jahn et al. 2024), which would decrease albedo in the Arctic region.

• Global
  • Decreases of 0.1°C up to 1.6°C by 2100
    • Decrease of 0.1°C by 2050 and up to 1.6°C by 2100 (not accounting for extra warming that may occur from unmasking cooling from aerosol pollution) if CO₂ emissions peak in 2030 and carbon neutrality reached 2060-2070 (Xu and Ramanathan 2017 in Zaelke et al. 2023).
    • Decarbonization alone will breach 2.0°C by 2045, even more aggressive mitigation scenarios proposed by the IPCC (Dreyfus et al. 2022). This impact is partly due to unmasking the cooling effect of co-emitted aerosols (Dreyfus et al. 2022).
    • Implementing unconditional Nationally Determined Contributions (NDCs) made under the Paris Agreement would decrease temperatures by approximately 0.5°C compared to current policies continuing, however this corresponds to a mean global temperature of approximately 2.9°C above pre-industrial temperatures (UNEP 2023).
    • The NZE Scenario with rapid emissions cuts in the Net Zero Roadmap by the International Energy Association (2023) keeps overall warming below 1.5°C by 2100 with low overshoot as defined by the IPCC. Note that this scenario also includes methane emissions reductions.
• Arctic region
  • Decreases of 6°C by 2100
    • Compared to no emissions reductions and mitigation, Arctic temperatures would decrease 6°C by 2100 with emissions reductions. However, the mean Arctic temperature would still be 7°C higher compared to baseline temperatures (Williams 2021).

• Global
  • Unknown
    • Most references of radiative forcing change are reported for total GHGs and not due to CO₂ emissions reductions alone
    • Estimates provided in Dreyfus et al. (2022) are in °C, not in radiative forcing units.
  • Arctic region
    • Unknown

• Direct or indirect impact on sea ice?
  • Indirect
• New or old ice?
  • Both
• Impact on sea ice
  • All emissions scenarios predict ice-free conditions in the Arctic in September by 2050 (reviewed in Jahn et al. 2024).
  • If emissions reductions limit warming to < 1.5°C there is <10% chance that the Arctic would not become ice free (Jahn et al. 2024).
  • With emissions reductions consistent with Shared Socioeconomic Pathway (SSP)1-1.9, consistently ice-free conditions would be limited to September (Jahn et al. 2024).
  • As emissions reductions increase and temperatures decrease, sea ice has the ability to come back even if ice-free conditions appear (Jahn et al. 2024).

Scalability

• Depends on technology and region
  • For renewable energy, scalability is limited by site suitability and conflicts with other uses.
  • For renewable energy, advanced economies are on track to achieve contributions to global goals, however, policies and international support are needed to advance progress of developing economies (IEA 2023)

• Depends on technology

• Unknown
  • While many technologies are already technically feasible, permitting, infrastructure development, supply chain issues, and integration of renewable energy sources are current barriers to scalability (IEA 2023).

• Possible, but unlikely. Substantial and rapid emissions reductions are needed with CO₂ emissions peaking by or before 2030 and net zero achieved in the following decades (Xu and Ramanathan 2017, IEA 2023). Projected emissions trajectories imply that warming will exceed 1.5°C (IPCC 2022).

• Likely > 20 years. All emissions scenarios predict ice-free conditions in the Arctic in September by 2050 (reviewed in Jahn et al. 2024). As emissions reductions increase over time and temperatures further decrease, sea ice does have the ability to rebound (Jahn et al. 2024).

Cost

• $4.5 trillion USD/year needed to invest in clean energy by the early 2030s (IEA 2023).
• An overview of emissions reductions options with estimated costs and potentials is available in IPCC ARG Working Group 3 report.
• In addition to the economic cost to decarbonize, there is also a cost associated with the lack of appropriate decarbonization. This is represented by the social cost of carbon (SCC), which estimates the economic damage resulting from emissions per ton of carbon dioxide. A 2022 study by Rennert et al. recommended that the SCC be set to $185/tCO₂. The SCC is currently set at $190/tCO₂ for the United States Government.

• Unknown

• Varies depending on technology, but many are 9
• Summary of existing literature and studies
  • Many technologies already exist and are operational (IEA 2023).
  • Only 35% of technologies needed by 2050 to reach net zero are not available on the market (IEA 2023).

• Likely feasible
  • Increasing the use of renewable energy and improving energy efficiency using technologies available today, coupled with cutting methane emissions, would provide >80% of emissions reductions needed by 2030 (IEA 2023). Strong growth in clean energy is required (IEA 2023).

• • Varies depending on technology, but many are 9
  • Summary of existing literature and studies
    • Many technologies already exist and are operational (IEA 2023).
    • Only 35% of technologies needed by 2050 to reach net zero are not available on the market (IEA 2023).

• • Likely feasible
    • Increasing the use of renewable energy and improving energy efficiency using technologies available today, coupled with cutting methane emissions, would provide >80% of emissions reductions needed by 2030 (IEA 2023). Strong growth in clean energy is required (IEA 2023).

• TRL
  • Varies depending on technology, but many are 9
  • Summary of existing literature and studies
    • Many technologies already exist and are operational (IEA 2023).
    • Only 35% of technologies needed by 2050 to reach net zero are not available on the market (IEA 2023).
• Technology feasibility within 10 years
  • Likely feasible
    • Increasing the use of renewable energy and improving energy efficiency using technologies available today, coupled with cutting methane emissions, would provide >80% of emissions reductions needed by 2030 (IEA 2023). Strong growth in clean energy is required (IEA 2023).

Physical and chemical changes

• Co-benefits
  • Improved air quality (UNEP 2023).
  • Some pathways may also reduce CH₄ and N₂O emissions (IPCC 2022).
• Risks
  • Reducing CO₂ emissions will also reduce emissions of aerosols that have a cooling effect. The loss of the cooling effect from offsets will likely offset reductions in temperature from reduced CO₂ emissions until approximately 2050 or potentially accelerate warming for about 10 years or more (Dreyfus et al. 2022).

Impacts on species

• Co-benefits
  • Potential for reduced deforestation (IPCC 2022).
• Risks
  • Potential for limiting animal migrations or movements (e.g. dams in rivers, windmills).

Impacts on ecosystem

• Co-benefits
  • Potential for reduced deforestation (IPCC 2022).
• Risks
  • Reduced biodiversity for projects operating at a large scale that require new infrastructure (IPCC 2022). Habitat fragmentation caused by large-scale infrastructure development.

Impacts on society

• Co-benefits
  • Strengthen economies (NASEM 2021).
  • Promote equity and inclusion (NASEM 2021).
  • Support communities, businesses, and workers (NASEM 2021, UNEP 2023).
  • Energy security (IEA 2023).
  • Improved air quality and subsequent health benefits (UNEP 2023).
  • The more effort placed into decarbonization, the less need there will be for carbon dioxide removal in the long term to limit overshoot (IPCC 2022).
  • Many decarbonization options have synergies with Sustainable Development Goals (see IPCC ARG Working Group 3 report; e.g. creating sustainable cities and communities and supporting good health and wellbeing).
• Risks
  • Supply chain shortages may slow decarbonization efforts or make them more expensive, especially due to demand for critical minerals (IEA 2023).
  • Increasing digitalization that can increase energy efficiency is also associated with increasing electronic waste and negative impacts on labor markets (IPCC 2022).
  • Some decarbonization options pose tradeoffs with current land usage (e.g. dams flooding river valleys).
  • Some decarbonization options pose tradeoffs with Sustainable Development Goals (see IPCC ARG Working Group 3 report; e.g., negative effects on maintaining clean water and sanitation).

Ease of reversibility

• Easy
  • Easily reversible, although significant infrastructure will be required for carbon dioxide emissions reductions.

Risk of termination shock

• No risk

Physical and chemical changes

• Co-benefits
  • Improved air quality (UNEP 2023).
  • Some pathways may also reduce CH₄ and N₂O emissions (IPCC 2022).
• Risks
  • Reducing CO₂ emissions will also reduce emissions of aerosols that have a cooling effect. The loss of the cooling effect from offsets will likely offset reductions in temperature from reduced CO₂ emissions until approximately 2050 or potentially accelerate warming for about 10 years or more (Dreyfus et al. 2022).

Impacts on species

• Co-benefits
  • Potential for reduced deforestation (IPCC 2022).
• Risks
  • Potential for limiting animal migrations or movements (e.g. dams in rivers, windmills).

Impacts on ecosystem

• Co-benefits
  • Potential for reduced deforestation (IPCC 2022).
• Risks
  • Reduced biodiversity for projects operating at a large scale that require new infrastructure (IPCC 2022). Habitat fragmentation caused by large-scale infrastructure development.

Impacts on society

• Co-benefits
  • Strengthen economies (NASEM 2021).
  • Promote equity and inclusion (NASEM 2021).
  • Support communities, businesses, and workers (NASEM 2021, UNEP 2023).
  • Energy security (IEA 2023).
  • Improved air quality and subsequent health benefits (UNEP 2023).
  • The more effort placed into decarbonization, the less need there will be for carbon dioxide removal in the long term to limit overshoot (IPCC 2022).
  • Many decarbonization options have synergies with Sustainable Development Goals (see IPCC ARG Working Group 3 report;g. creating sustainable cities and communities and supporting good health and wellbeing).
• Risks
  • Supply chain shortages may slow decarbonization efforts or make them more expensive, especially due to demand for critical minerals (IEA 2023).
  • Increasing digitalization that can increase energy efficiency is also associated with increasing electronic waste and negative impacts on labor markets (IPCC 2022).
  • Some decarbonization options pose tradeoffs with current land usage (e.g. dams flooding river valleys).
  • Some decarbonization options pose tradeoffs with Sustainable Development Goals (see IPCC ARG Working Group 3 report; e.g., negative effects on maintaining clean water and sanitation).

Ease of reversibility

• Easy
  • Easily reversible, although significant infrastructure will be required for carbon dioxide emissions reductions.

Risk of termination shock

• No risk

Physical and chemical changes

• Co-benefits
  • Improved air quality (UNEP 2023).
  • Some pathways may also reduce CH₄ and N₂O emissions (IPCC 2022).
• Risks
  • Reducing CO₂ emissions will also reduce emissions of aerosols that have a cooling effect. The loss of the cooling effect from offsets will likely offset reductions in temperature from reduced CO₂ emissions until approximately 2050 or potentially accelerate warming for about 10 years or more (Dreyfus et al. 2022).

Impacts on species

• Co-benefits
  • Potential for reduced deforestation (IPCC 2022).
• Risks
  • Potential for limiting animal migrations or movements (e.g. dams in rivers, windmills).

Impacts on ecosystem

• Co-benefits
  • Potential for reduced deforestation (IPCC 2022).
• Risks
  • Reduced biodiversity for projects operating at a large scale that require new infrastructure (IPCC 2022). Habitat fragmentation caused by large-scale infrastructure development.

Impacts on society

• Co-benefits
  • Strengthen economies (NASEM 2021).
  • Promote equity and inclusion (NASEM 2021).
  • Support communities, businesses, and workers (NASEM 2021, UNEP 2023).
  • Energy security (IEA 2023).
  • Improved air quality and subsequent health benefits (UNEP 2023).
  • The more effort placed into decarbonization, the less need there will be for carbon dioxide removal in the long term to limit overshoot (IPCC 2022).
  • Many decarbonization options have synergies with Sustainable Development Goals (see IPCC ARG Working Group 3 report;g. creating sustainable cities and communities and supporting good health and wellbeing).
• Risks
  • Supply chain shortages may slow decarbonization efforts or make them more expensive, especially due to demand for critical minerals (IEA 2023).
  • Increasing digitalization that can increase energy efficiency is also associated with increasing electronic waste and negative impacts on labor markets (IPCC 2022).
  • Some decarbonization options pose tradeoffs with current land usage (e.g. dams flooding river valleys).
  • Some decarbonization options pose tradeoffs with Sustainable Development Goals (see IPCC ARG Working Group 3 report; e.g., negative effects on maintaining clean water and sanitation).

Ease of reversibility

• Easily reversible, although significant infrastructure will be required for carbon dioxide emissions reductions.

Risk of termination shock

• Unlikely

• Co-benefits
  • Improved air quality (UNEP 2023).
  • Some pathways may also reduce CH₄ and N₂O emissions (IPCC 2022).
• Risks
  • Reducing CO₂ emissions will also reduce emissions of aerosols that have a cooling effect. The loss of the cooling effect from offsets will likely offset reductions in temperature from reduced CO₂ emissions until approximately 2050 or potentially accelerate warming for about 10 years or more (Dreyfus et al. 2022).

• Co-benefits
  • Potential for reduced deforestation (IPCC 2022).
• Risks
  • Potential for limiting animal migrations or movements (e.g. dams in rivers, windmills).

• Co-benefits
  • Potential for reduced deforestation (IPCC 2022).
• Risks
  • Reduced biodiversity for projects operating at a large scale that require new infrastructure (IPCC 2022). Habitat fragmentation caused by large-scale infrastructure development.

• Co-benefits
  • Strengthen economies (NASEM 2021).
  • Promote equity and inclusion (NASEM 2021).
  • Support communities, businesses, and workers (NASEM 2021, UNEP 2023).
  • Energy security (IEA 2023).
  • Improved air quality and subsequent health benefits (UNEP 2023).
  • The more effort placed into decarbonization, the less need there will be for carbon dioxide removal in the long term to limit overshoot (IPCC 2022).
  • Many decarbonization options have synergies with Sustainable Development Goals (see IPCC ARG Working Group 3 report;g. creating sustainable cities and communities and supporting good health and wellbeing).
• Risks
  • Supply chain shortages may slow decarbonization efforts or make them more expensive, especially due to demand for critical minerals (IEA 2023).
  • Increasing digitalization that can increase energy efficiency is also associated with increasing electronic waste and negative impacts on labor markets (IPCC 2022).
  • Some decarbonization options pose tradeoffs with current land usage (e.g. dams flooding river valleys).
  • Some decarbonization options pose tradeoffs with Sustainable Development Goals (see IPCC ARG Working Group 3 report; e.g., negative effects on maintaining clean water and sanitation).

• Easily reversible, although significant infrastructure will be required for carbon dioxide emissions reductions.

• Unlikely

• Co-benefits
  • Improved air quality (UNEP 2023).
  • Some pathways may also reduce CH₄ and N₂O emissions (IPCC 2022).
• Risks
  • Reducing CO₂ emissions will also reduce emissions of aerosols that have a cooling effect. The loss of the cooling effect from offsets will likely offset reductions in temperature from reduced CO₂ emissions until approximately 2050 or potentially accelerate warming for about 10 years or more (Dreyfus et al. 2022).

• Co-benefits
  • Potential for reduced deforestation (IPCC 2022).
• Risks
  • Potential for limiting animal migrations or movements (e.g. dams in rivers, windmills).

• Co-benefits
  • Potential for reduced deforestation (IPCC 2022).
• Risks
  • Reduced biodiversity for projects operating at a large scale that require new infrastructure (IPCC 2022). Habitat fragmentation caused by large-scale infrastructure development.

• Co-benefits
  • Strengthen economies (NASEM 2021)
  • Promote equity and inclusion (NASEM 2021)
  • Support communities, businesses, and workers (NASEM 2021, UNEP 2023)
  • Energy security (IEA 2023)
  • Improved air quality and subsequent health benefits (UNEP 2023)
  • The more effort placed into decarbonization, the less need there will be for carbon dioxide removal in the long term to limit overshoot (IPCC 2022).
  • Many decarbonization options have synergies with Sustainable Development Goals (see IPCC ARG Working Group 3 report;g. creating sustainable cities and communities and supporting good health and wellbeing).
• Risks
  • Supply chain shortages may slow decarbonization efforts or make them more expensive, especially due to demand for critical minerals (IEA 2023).
  • Increasing digitalization that can increase energy efficiency is also associated with increasing electronic waste and negative impacts on labor markets (IPCC 2022).
  • Some decarbonization options pose tradeoffs with current land usage (e.g. dams flooding river valleys).
  • Some decarbonization options pose tradeoffs with Sustainable Development Goals (see IPCC ARG Working Group 3 report; e.g., negative effects on maintaining clean water and sanitation).

• Easily reversible, although significant infrastructure will be required for carbon dioxide emissions reductions.

• Unlikely

• Co-benefits
  • Improved air quality (UNEP 2023).
  • Some pathways may also reduce CH₄ and N₂O emissions (IPCC 2022).
• Risks
  • Reducing CO₂ emissions will also reduce emissions of aerosols that have a cooling effect. The loss of the cooling effect from offsets will likely offset reductions in temperature from reduced CO₂ emissions until approximately 2050 or potentially accelerate warming for about 10 years or more (Dreyfus et al. 2022).

• Co-benefits
  • Potential for reduced deforestation (IPCC 2022).
• Risks
  • Potential for limiting animal migrations or movements (e.g. dams in rivers, windmills)

• Co-benefits
  • Potential for reduced deforestation (IPCC 2022).
• Risks
  • Reduced biodiversity for projects operating at a large scale that require new infrastructure (IPCC 2022). Habitat fragmentation caused by large-scale infrastructure development.

• Co-benefits
  • Strengthen economies (NASEM 2021)
  • Promote equity and inclusion (NASEM 2021)
  • Support communities, businesses, and workers (NASEM 2021, UNEP 2023)
  • Energy security (IEA 2023)
  • Improved air quality and subsequent health benefits (UNEP 2023)
  • The more effort placed into decarbonization, the less need there will be for carbon dioxide removal in the long term to limit overshoot (IPCC 2022).
  • Many decarbonization options have synergies with Sustainable Development Goals (see IPCC ARG Working Group 3 report;g. creating sustainable cities and communities and supporting good health and wellbeing).
• Risks
  • Supply chain shortages may slow decarbonization efforts or make them more expensive, especially due to demand for critical minerals (IEA 2023).
  • Increasing digitalization that can increase energy efficiency is also associated with increasing electronic waste and negative impacts on labor markets (IPCC 2022).
  • Some decarbonization options pose tradeoffs with current land usage (e.g. dams flooding river valleys).
  • Some decarbonization options pose tradeoffs with Sustainable Development Goals (see IPCC ARG Working Group 3 report;g. negative effects on maintaining clean water and sanitation).

• Easily reversible, although significant infrastructure will be required for carbon dioxide emissions reductions.

• Unlikely

• Most action on carbon dioxide is occurring at the national level, with non-binding action at the international level.

• Countries have Nationally Determined Contributions (NDCs) made under the international Paris Agreement. NDCs are subsequently evaluated through the Global Stocktake. The first global stocktake took place during COP28. The preambles of the Paris Agreement say that countries should, when taking action to address climate change, consider their human rights obligations.
• As of 2020, 56 countries covering 53% of global emissions have climate laws focused on emissions reductions (IPCC 2022).
• National climate institutions address coordination among groups at various scales, build consensus for action, and inform strategy setting (IPCC 2022). Such action has often been accomplished through independent expert groups and coordinating bodies (IPCC 2022).

• 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
  • Most clean energy investment is happening in advanced economies and China; investment is needed in emerging and developing economies (IEA 2023, IPCC 2022). The majority of clean energy supplied is used by people who live in advanced economies (IEA 2023). To address this disparity the following barriers need to be addressed: 1) access to finance, 2) supportive policy environment, 3) increase in technology diffusion and support for innovation in developing economies.
  • There are distributional consequences to some emissions reduction activities within and between countries that include shifting of income and employment (IPCC 2022). Just transition principles and implementation are necessary for integrating equity principles and are already taking place in many countries and regions (IPCC 2022).
  • Each individual emissions reductions pathway will have specific distributional justice concerns, which will also vary by region and country. For a review focused largely on distributional justice related to the clean energy transition, see Bennear (2022).
• Procedural justice
  • Opportunities for participation in governance of emissions reductions have increased over time. Localized actions can enable participation but can be limited by resource and capacity constraints (IPCC 2022).
  • Each individual emissions reductions pathway will have specific procedural justice concerns, which will also vary by region and country.
• Restorative justice
  • Each individual emissions reductions pathway will have specific restorative justice concerns, which will also vary by region and country.
  • Climate-related litigation by governments, private sector, civil society and individuals has provided some opportunities for restorative justice and has influenced the outcome and ambition of climate governance (IPCC 2022).

• Political support for climate change mitigation and resulting policy changes are influenced by the extent to which a diverse set of communities and groups are engaged (IPCC 2022).
• Many emissions reduction options are generally supported by the public (IPCC 2022).

• Many aspirations for engagement and inclusion of Indigenous peoples in decarbonization policies have not been realized (e.g., Reed et al. 2021). Some plans for wind and solar energy installations as well as mining operations require large amounts of land and threaten Indigenous Peoples’ lands and way of life. In the Arctic, the construction of Europe’s largest onshore wind farm in Norway violated the rights of the Sami people (Associated Press 2024). A recent agreement keeps the wind farm in operation and safeguards reindeer farming rights and provides compensation to the Sami people of Norway (Associated Press 2024).

• Most action on carbon dioxide is occurring at the national level, with non-binding action at the international level.

• Countries have Nationally Determined Contributions (NDCs) made under the international Paris Agreement. NDCs are subsequently evaluated through the Global Stocktake. The first global stocktake took place during COP28. The preambles of the Paris Agreement say that countries should, when taking action to address climate change, consider their human rights obligations.
• As of 2020, 56 countries covering 53% of global emissions have climate laws focused on emissions reductions (IPCC 2022).
• National climate institutions address coordination among groups at various scales, build consensus for action, and inform strategy setting (IPCC 2022). Such action has often been accomplished through independent expert groups and coordinating bodies (IPCC 2022).

• 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
  • Most clean energy investment is happening in advanced economies and China; investment is needed in emerging and developing economies (IEA 2023, IPCC 2022). The majority of clean energy supplied is used by people who live in advanced economies (IEA 2023). To address this disparity the following barriers need to be addressed: 1) access to finance, 2) supportive policy environment, 3) increase in technology diffusion and support for innovation in developing economies.
  • There are distributional consequences to some emissions reduction activities within and between countries that include shifting of income and employment (IPCC 2022). Just transition principles and implementation are necessary for integrating equity principles and are already taking place in many countries and regions (IPCC 2022).
  • Each individual emissions reductions pathway will have specific distributional justice concerns, which will also vary by region and country. For a review focused largely on distributional justice related to the clean energy transition, see Bennear (2022).
• Procedural justice
  • Opportunities for participation in governance of emissions reductions have increased over time. Localized actions can enable participation but can be limited by resource and capacity constraints (IPCC 2022).
  • Each individual emissions reductions pathway will have specific procedural justice concerns, which will also vary by region and country.
• Restorative justice
  • Each individual emissions reductions pathway will have specific restorative justice concerns, which will also vary by region and country.
  • Climate-related litigation by governments, private sector, civil society and individuals has provided some opportunities for restorative justice and has influenced the outcome and ambition of climate governance (IPCC 2022).

• Political support for climate change mitigation and resulting policy changes are influenced by the extent to which a diverse set of communities and groups are engaged (IPCC 2022).
• Many emissions reduction options are generally supported by the public (IPCC 2022).

• Many aspirations for engagement and inclusion of Indigenous peoples in decarbonization policies have not been realized (e.g., Reed et al. 2021). Some plans for wind and solar energy installations as well as mining operations require large amounts of land and threaten Indigenous Peoples’ lands and way of life. In the Arctic, the construction of Europe’s largest onshore wind farm in Norway violated the rights of the Sami people (Associated Press 2024). A recent agreement keeps the wind farm in operation and safeguards reindeer farming rights and provides compensation to the Sami people of Norway (Associated Press 2024).

• Most action on carbon dioxide is occurring at the national level, with non-binding action at the international level.

• Countries have Nationally Determined Contributions (NDCs) made under the international Paris Agreement. NDCs are subsequently evaluated through the Global Stocktake. The first global stocktake took place during COP28. The preambles of the Paris Agreement say that countries should, when taking action to address climate change, consider their human rights obligations.
• As of 2020, 56 countries covering 53% of global emissions have climate laws focused on emissions reductions (IPCC 2022).
• National climate institutions address coordination among groups at various scales, build consensus for action, and inform strategy setting (IPCC 2022). Such action has often been accomplished through independent expert groups and coordinating bodies (IPCC 2022).

• Distributive justice
  • Most clean energy investment is happening in advanced economies and China; investment is needed in emerging and developing economies (IEA 2023, IPCC 2022). The majority of clean energy supplied is used by people who live in advanced economies (IEA 2023). To address this disparity the following barriers need to be addressed: 1) access to finance, 2) supportive policy environment, 3) increase in technology diffusion and support for innovation in developing economies.
  • There are distributional consequences to some emissions reduction activities within and between countries that include shifting of income and employment (IPCC 2022). Just transition principles and implementation are necessary for integrating equity principles and are already taking place in many countries and regions (IPCC 2022).
  • Each individual emissions reductions pathway will have specific distributional justice concerns, which will also vary by region and country. For a review focused largely on distributional justice related to the clean energy transition, see Bennear (2022).
• Procedural justice
  • Opportunities for participation in governance of emissions reductions have increased over time. Localized actions can enable participation but can be limited by resource and capacity constraints (IPCC 2022).
  • Each individual emissions reductions pathway will have specific procedural justice concerns, which will also vary by region and country.
• Restorative justice
  • Each individual emissions reductions pathway will have specific restorative justice concerns, which will also vary by region and country.
  • Climate-related litigation by governments, private sector, civil society and individuals has provided some opportunities for restorative justice and has influenced the outcome and ambition of climate governance (IPCC 2022).

• Political support for climate change mitigation and resulting policy changes are influenced by the extent to which a diverse set of communities and groups are engaged (IPCC 2022).
• Many emissions reduction options are generally supported by the public (IPCC 2022).

• Many aspirations for engagement and inclusion of Indigenous peoples in decarbonization policies have not been realized (e.g., Reed et al. 2021). Some plans for wind and solar energy installations as well as mining operations require large amounts of land and threaten Indigenous Peoples’ lands and way of life. In the Arctic, the construction of Europe’s largest onshore wind farm in Norway violated the rights of the Sami people (Associated Press 2024). A recent agreement keeps the wind farm in operation and safeguards reindeer farming rights and provides compensation to the Sami people of Norway (Associated Press 2024).