Strong contribution of SO2 emissions reductions from China to global warming intensification since 2010

The rate of global warming has seemingly increased since around 2010, relative to the previous 30-year period, leading up to the recent strong records in global surface temperature anomalies set in 2023 and 2024. Concurrently, Chinese emissions of SO₂ have dropped dramatically as a consequence of strong national air quality policies. This has, in turn, led to marked reductions in atmospheric sulphate aerosol loadings over, and downwind from, the Chinese mainland, as well as strong improvements in air quality. To date, the contribution of Chinese emissions reductions to the intensification of global warming, through unmasking of greenhouse gas driven climate change, has however not been quantified.

Here, we use simulations from the Regional Aerosol Model Intercomparison Project (RAMIP) to investigate the climate response to strong reductions in Chinese SO₂ emissions, closely analogous to real-world changes since 2010. We use 10-member ensembles of fully coupled simulations from ten CMIP6 era Global Climate Models, to quantify the global and regional, seasonally resolved influences on temperature and precipitation in a total of 100 ensemble members.

Overall, we find a warming due to recent reductions in SO₂ emissions from China of 0.07 ± 0.05 ºC. Assuming that this has happened since 2010 leads to a warming rate of 0.05 ºC / decade. Recent observations of global surface temperature anomalies indicate a warming rate increase of 0.07 ºC / decade, when filtered for the effects of interannual variability in sea surface temperature patterns. Hence, our results indicate a strong contribution of aerosol emissions reductions to this elevated warming rate. This conclusion is supported by the geographical pattern of elevated warming, as well as correspondence between modelled and observed top-of-atmosphere radiative imbalance changes.