Abstract/Summary

With the rapid progression of global climate warming, the southern China is facing severe challenges related to extreme precipitation. Based on the multi-model ensembles of CMIP6 simulations, the future changes in extreme precipitation in the southern China at various global warming levels (GWLs) under the SSP2-4.5, SSP3-7.0, and SSP5-8.5 are investigated and the likelihood of rare events like those occurred during April–June 2022 is assessed. As global surface temperatures rise, the southern China is expected to experience more frequent and intense extreme precipitation events compared to those in the recent climate. The changes in magnitudes of precipitation extremes and the likelihood of rare events primarily depend on the GWLs, but they are not very sensitive to the scenarios. Under SSP5-8.5 at 1.5 °C, 2 °C, 3 °C and 4 °C GWLs, the probability of Rx30day similar to the 2022 event increases by 3.64, 3.87, 8.68, and 15.46 times relative to the current climate, respectively. We further evaluated the thermodynamic and dynamic mechanisms driving seasonal mean precipitation changes using the moisture budget equation. The results indicate that changes in moisture flux convergence are mainly caused by thermodynamic effects, while dynamic effects play a negative role. Compared to SSP2-4.5 and SSP5-8.5, the increase in seasonal precipitation under SSP3-7.0 tends to be weaker, related to increased aerosol changes under SSP3-7.0. These findings reveal a strong sensitivity of changes in extreme precipitation in the southern China to GWLs, but less sensitivity to emission scenarios at the same GWLs, providing useful information for climate change mitigation policy in this region.