A canonical response of precipitation characteristics to global warming from CMIP5 models

Abstract

In this study, we find from analyses of projections of 14 CMIP5 models a robust, canonical global response in rainfall characteristics to a warming climate. Under a scenario of 1% increase per year of CO2 emission, the model ensemble projects globally more heavy precipitation (+7 - 2.4%K -1), less moderate precipitation (-2.5 - 0.6%K-1), more light precipitation (+1.8 - 1.3%K-1), and increased length of dry (no-rain) periods (+4.7 - 2.1%K-1). Regionally, a majority of the models project a consistent response with more heavy precipitation over climatologically wet regions of the deep tropics, especially the equatorial Pacific Ocean and the Asian monsoon regions, and more dry periods over the land areas of the subtropics and the tropical marginal convective zones. Our results suggest that increased CO2 emissions induce a global adjustment in circulation and moisture availability manifested in basic changes in global precipitation characteristics, including increasing risks of severe floods and droughts in preferred geographic locations worldwide. Key Points A canonical rainfall response is found in CMIP-5 models increased floods and droughts under global warming are connected Changing rainfall types are more sensitive than total rainfall ©2013. American Geophysical Union. All Rights Reserved.