Increased Population Exposure to Heat and Wet Extremes Moving From Chinese to Global 1.5 or 2.0°C Warming.

The Paris Agreement proposed two global warming levels relative to the preindustrial period, with the ideal objective of 1.5°C warming and an upper boundary of 2.0 °C. However, the years when the temperature will first reach 1.5 or 2.0°C vary in different regions. Therefore, climate extremes and their population exposure are still not clear at regional or global warming levels. This study investigated climate extremes in China at different Chinese and global warming with 16 CMIP6 models under the middle SSP245 scenario. In China, the year when 1.5°C warming is projected to occur is 2020 and 2035 for 2.0°C warming. These values are more than 10 years earlier than the corresponding global warming levels of 2030 and 2049. Population exposure to percentile‐based heat extremes at global 1.5°C warming is projected to greatly increase relative to those when 1.5°C warming occurs in China due to increases in climate extremes, and exposure to absolute heat extreme indices is projected to decrease from Chinese to global 2.0°C warming under the joint impacts of increases in extremes and population decreases. Furthermore, from Chinese to global 1.5°C warming, about 344 million people will experience increased exposure to heat, wet and dry extremes, and around 468 and 371 million people will be affected by increased exposure to heat–wet and heat–dry extremes, respectively. Thus, a more adaptive strategy should be proposed to cope with the future possible natural hazards caused by heat–wet and heat–dry extremes. Plain Language Summary: In general, heat extremes are projected to increase in a warmer climate. However, changes in surface air temperature will vary among different regions at regional and global warming levels which might impact future climate extremes and their population exposure. The heat extremes, heavy precipitation amount and consecutive days with no precipitation, and population exposure to these extremes were investigated at global and Chinese 1.5 or 2.0°C warming levels. The years when 1.5 and 2.0°C warming will occur in China are more than 10 years earlier than those of global warming levels, respectively. About 344 million people will be involved in increased exposure to above three types of extremes moving from Chinese to global 1.5°C warming. Thus, more adaptive strategies should be established to cope with the possible increased risks in the future. Key Points: Warming by 1.5 and 2.0°C will occur more than 10 years earlier in China compared with global warming levelsPopulation exposure to percentile‐based heat extremes in China is projected to greatly increase from Chinese to global 1.5°C warmingAbout 400 million people will experience increased exposure to heat–wet and heat–dry extremes from Chinese to global 1.5°C warming [ABSTRACT FROM AUTHOR]