1.5℃ and 2.0℃ of global warming intensifies the hydrological extremes in China

Abstract

Global warming has been shown to have a profound impact on hydrological process, especially on hydrological extremes. To avoid the potential risk of extreme hazards, it is essential to project changes in hydroclimatic extremes under the 1.5℃ and 2.0℃ targets of the Paris Agreement, especially in China, which is geographically, climatologically, economically, and socially complex. Here, this study projects future changes in hydroclimatic extremes in China under 1.5℃ and 2.0℃ warming targets based on a distributed hydrological model driven by an ensemble of downscaled general circulation models. The study shows that global warming of 1.5℃ and 2.0℃ would perceptibly affect the spatial patterns of extreme rainfall and extreme heat in China. The intensification of events such as extreme rainfall, meteorological drought, and extreme heat would intensify the hydrological extremes, including floods and hydrological droughts. The risk of future extreme floods and hydrological droughts will increase simultaneously, with a 34.6% (38.0%) probability of acceleration (more severe floods and droughts) in a 1.5℃ (2.0℃) warming world. Correspondingly, global warming tends to exacerbate the water cycle, with a 92.5% (94.2%) probability that at least one extreme event will exhibit intensification characteristics in the 1.5℃ (2.0℃) warming scenario. The acceleration of the water cycle and the intensification of the hydrological extremes may have adverse impacts on the balanced development of China's ecological and economic society.