Earlier carbon neutrality more effectively limits heat exposure of urban populations in developing continents

Abstract Achieving carbon neutrality by the 2050s, as proposed in the Paris Agreement, is imperative for mitigating climate risks and fostering a sustainable future. Here, by examining the multi-model projections under the Coupled Model Intercomparison Project Phase 6 shared socioeconomic pathway scenarios, we show that achieving carbon neutrality by the 2050s shared socioeconomic pathway (SSP) 1-1.9 can reduce global population exposure (PE) to hot temperature extremes—defined as person-days exceeding the 30 year return value of annual maximum daily maximum temperature—by 98%, compared to the scenario of continued regional rivalry in carbon emissions (SSP3-7.0). It is also up to 7% more effective than achieving carbon neutrality by the 2070s (SSP1-2.6), with this additional benefit driven primarily by significant reductions in urban PE, 4–9 times greater than those in rural PE. The effects of earlier carbon neutrality are particularly greater in developing continents, such as Africa, Asia, and South America, than in developed continents, thereby helping to reduce the regional inequality in climate risks. This result underscores the urgency of pursuing earlier carbon neutrality to reduce climate risks, especially in developing continents.