Additional Intensification of Seasonal Heat and Flooding Extreme Over China in a 2°C Warmer World Compared to 1.5°C

Abstract

The Paris Agreement commits to stabilizing global mean surface warming to below 2°C (above preindustrial levels) and strives to limit it to 1.5°C to mitigate the risks of anthropogenic climate change. This study explores the impacts of stabilized 1.5°C and 2°C warming in the late 21st century on seasonal climate extremes over China by using a set of coupled Earth system model simulations explicitly targeting these warming levels. Our results show that global warming levels of 1.5°C and 2°C will lead to increases in surface air temperature (precipitation) averaged over China of 1.3°C and 1.9°C (11.6% and 13.3%), respectively, compared to 1976–2005. Climate extremes over China will become more frequent in a warmer world. Relative to the 1976–2005, the frequency of events similar to the 2013 extreme hot summer in eastern China and extreme flooding during the summer of 2010 in southeastern China will increase by 16 or 33 times and 2 or 3 times, respectively, given a global temperature increase of 1.5°C or 2°C. In particular, events similar to the 2013 extreme hot summer will occur almost yearly in a 2°C warmer world. The likelihood of an event similar to the 2014 extreme hot spring in northeastern China will increase to 8% or 20% in a 1.5°C or 2°C warmer world, whereas such events were rare during 1976–2005. Given these dangerous consequences, we conclude that there are discernible benefits for China to contribute to the global decarbonization effort to limit global warming to below 1.5°C rather than 2°C.