Considering the interplay between sectoral co-emissions of warmers, coolers, and their lifespans can improve the design of climate change mitigation policies

Anthropogenic greenhouse gas emissions are typically a mix of warmers/coolers and short-lived/long-lived species. This suite of emissions should be taken into account to drive better outcomes. We quantify 33 emitted species since 1750 from seven economic sectors and their impact on present-day warming. We then assess how today’s sectoral emissions impact future temperatures. Sectors that predominantly emit short-lived warmers drive half of today’s warming (~ 0.6°C). However, their current-year emissions have a lesser impact on 100-year temperature projections due to proportionally lower longer-lived species. Sectoral emissions dominated by longer-lived warmers impact temperature for centuries – an impact which accumulates over time. However, shorter-lived climate coolers from these sectors mask ~ 50% of their present-day warming (~ 33% overall). This means actions necessary to reduce long-lived warming may temporarily increase near-term temperatures. Successfully limiting both near- and long-term warming requires considering this interplay and accelerating climate ambitions to offset any decline in coolers.