Risks of Precipitation Extremes over Southeast Asia: Does 1.5 °C or 2 °C Global Warming Make a Difference?

Guided by the target of the Paris Agreement of 2015, it is fundamental to identify regional climate responses to global warming of different magnitudes for Southeast Asia (SEA), a tropical region where human society is particularly vulnerable to climate change. Projected changes in indices characterizing precipitation extremes of the 1.5 °C and 2 °C global warming levels (GWLs) exceeding pre-industrial conditions are analyzed, comparing the reference period (1976-2005) with an ensemble of CORDEX simulations. The results show that projected changes in precipitation extreme indices are significantly amplified over the Indochina Peninsula and the Maritime Continent at both GWLs. The increases of precipitation extremes are essentially affected by enhanced convective precipitation. The number of wet and extremely wet days is increasing more abruptly than both the total and daily average precipitation of all wet days, emphasizing the critical risks linked with extreme precipitation. Additionally, significant changes can also be observed between the GWLs of 1.5 °C and 2 °C, especially over the Maritime Continent, suggesting the high sensitivity of precipitation extremes to the additional 0.5 °C GWL increase. The present study reveals the potential influence of both 1.5 °C and 2 °C GWLs on regional precipitation over SEA, highlights the importance of restricting mean global warming to 1.5 °C above pre-industrial conditions and provides essential information on manageable climate adaptation and mitigation strategies for the developing countries in SEA.