Mitigating climate disruption in time: A self-consistent approach for avoiding both near-term and long-term global...

Area of Science:

• Climate Science
• Atmospheric Chemistry
• Environmental Policy

Background:

• Human-induced climate change necessitates urgent mitigation strategies for near-term (<2050) and long-term (>2050) warming.
• Fossil fuel (FF) phaseout by 2050 is a key decarbonization strategy, but its impact on non-CO2 greenhouse gases and aerosols requires clarification.

Purpose of the Study:

• To clarify the role of non-CO2 greenhouse gases and aerosols in climate mitigation.
• To assess the net effect of decarbonization strategies and their interaction with other climate forcers.
• To evaluate the efficacy of combined mitigation approaches for both near-term and long-term climate goals.

Main Methods:

• Utilized Intergovernmental Panel on Climate Change (IPCC) radiative forcing data.
• Analyzed historical radiative forcing from CO2 and non-CO2 forcers from FF and land-use changes.
• Modeled the impacts of decarbonization alone versus combined with non-CO2 mitigation strategies.

Main Results:

• Decarbonization alone, while crucial for long-term cooling, may cause near-term warming due to unmasked aerosol cooling effects, potentially exceeding 2°C before 2050.
• Mitigation targeting short-lived climate pollutants and nitrous oxide (N2O) alongside decarbonization slows warming earlier and avoids the 2°C threshold.
• Combined strategies can achieve net cooling by 2030 and halve the warming rate from 2030-2050, with methane contributing significantly.

Conclusions:

• A comprehensive approach combining CO2 reduction with targeted non-CO2 mitigation is essential.
• Addressing both near-term and long-term climate disruption requires a multifaceted strategy beyond solely decarbonization.
• Non-CO2 mitigation offers substantial co-benefits for near-term climate action and achieving long-term temperature goals.