Projected increases in population exposure of daily climate extremes in eastern China by 2050

Climate extremes pose severe threats to human health, economic stability and environmental sustainability, especially in densely populated areas. It is generally believed that global warming drives increase in frequency, intensity and duration of climate extremes, and socioeconomic exposure plays a dominant role in climate impacts. In order to promote climate risk governance at regional level, the historical and projected trends in the population exposure to climate extremes are quantified in eastern China using downscaled climate simulations and population growth scenarios. The frequency of temperature extremes (tx35days) is projected to more than double by 2050 in nearly half of prefecture-level cities in eastern China, leading to an 81.8% increment of total exposure under SSP2-4.5 scenario. The increasing trend is also detectable in the frequency of precipitation extremes (r20mm) in eastern China, and the exposure increment is projected to be 22.9% by 2050, with a near equivalent contributions of both climate change and population growth. Spatially, temperature exposure mainly grows in southern Hebei, western Shandong and inland Guangdong provinces, while precipitation exposure raises principally in southeast coastal areas of China. Based on the historical baseline and projected amplification of population exposure, we identify some hotspot cities such as Guangzhou, Shanghai, Dongguan and Hangzhou that response to climate change dramatically and confront greater potential risk of climate extremes in the coming future.