Fast action on short-lived climate pollutants and nature-based solutions to help countries meet carbon neutrality goals

Scientific studies show that fast actions to reduce near-term warming are essential to slowing self-reinforcing climate feedbacks and avoiding irreversible tipping points. Yet cutting CO2 emissions only marginally impacts near-term warming. This study identifies two of the most effective mitigation strategies to limit near-term warming beyond CO2 mitigation, namely reducing short-lived climate pollutants (SLCPs) and promoting targeted nature-based solutions (NbS), and comprehensively reviews the latest scientific progress in these fields. Studies show that quickly reducing SLCP emissions, particularly hydrofluorocarbons (HFCs), methane, and black carbon, from all relevant sectors can avoid up to 0.6 degrees C of warming by 2050. Additionally, promoting targeted NbS that protect and enhance natural carbon sinks, including in forests, wetlands, grasslands, and agricultural lands, can avoid emissions of 23.8 Gt of CO(2)e per year in 2030, without jeopardizing food security and biodiversity. Based on the scientific evidence, we provided a series of policy recommendations on SLCPs and NbS, including: 1) implementing the Kigali Amendment to reduce HFC emissions; 2) deploying cost-effective, sector-based measures to reduce methane and black carbon emissions; and 3) implementing targeted NbS to protect and enhance existing carbon sinks and shifting away from forest-burning bioenergy. These fast-acting strategies on SLCPs and NbS will play a key role in securing the most avoided warming in the near-term and help countries meet their mid-century carbon neutrality goals. Finally, we proposed future research topics, including: improving measurement and monitoring systems and techniques for SLCP emissions; developing and improving assessments of marginal abatement costs for SLCP mitigation in different sectors; better quantifying the avoided warming potential from protecting different types of natural carbon sinks by 2030, 2050, and over longer periods; and identifying whether there are any biomass types for energy sources that are consistent with the United Nations Environment Assembly's 2022 resolution adopting a definition of NbS. Further research in these areas could help address barriers to adoption and assist countries with better integrating the most effective SLCP and NbS strategies into their climate policies.