Thermodynamically enhanced precipitation extremes due to counterbalancing influences of anthropogenic greenhouse gases and aerosols

Responses of precipitation extremes to forcings by anthropogenic greenhouse gases (GHGs) and aerosol (AER) emissions could significantly impact society and ecosystems. Although human influences on changes in precipitation extremes are detectable, how precipitation extremes have responded to human-induced climate change remains unclear. Here we apply a robust physical scaling diagnostic on reanalysis-based and simulated precipitation extremes to disentangle global and regional changes in historical precipitation extremes to thermodynamic and dynamic contributions from anthropogenic GHGs and AER forcings. The results show that, despite large spatiotemporal uncertainties of dynamic contributions to regional changes in precipitation extremes, thermodynamic effects of anthropogenic GHGs (AER) significantly increase (decrease) the intensity of precipitation extremes. Since GHG positive effects are higher than AER negative effects, the counterbalancing effects enhance global precipitation extremes from 1960 to 2014. Increasing precipitation extremes are expected to be exacerbated in the future, given that GHG warming will continue to increase while AER cooling will decrease in the coming decades. Precipitation extremes could impact our society and ecosystems. This study investigates the historical intensification of extreme precipitation and the mechanisms by disentangling the contributions of different forcings.