Future changes in compound drought events and associated population and GDP exposure in China based on CMIP6

Compound drought events, in which several types of drought occur at the same time, usually causes more harm to human society than just one type of drought event on its own. In this study, skill scoring methods are used to evaluate models, and then several drought indices are calculated to characterize meteorological, agricultural, and hydrological droughts, separately. Finally, the projected future changes in compound drought events, and associated population and GDP exposure to them, are further studied based on CMIP6. The results show that the frequency of compound drought events is likely to increase in northern Northwest China, Southwest China, and South China, but decrease in North and Northeast China. The projected changes in duration and severity are similar to those of frequency, i.e., mainly increasing in a few parts of northern Northwest and South China, but decreasing in Northeast and North China. The population exposure to compound drought events is expected to increase greatly in the area south of the Yangtze River Basin, slightly in Northwest China, and decrease greatly in the northeast of the Yangtze River Basin. Both climate and population have important effects on the change in population exposure. Due to the expected rapid growth in GDP, the exposure of GDP to compound drought events in almost all regions of China is projected to increase in the future, especially in eastern China, and the relative contribution of the GDP effect to the change in GDP exposure will be the largest.

摘要

相较于一种类型的干旱, 几种类型的干旱同时发生的复合型干旱事件对人类社会造成的危害更加严重. 本研究采用CMIP6资料, 研究中国复合型干旱事件及其相关社会经济暴露度的未来变化. 结果表明, 西北北部, 西南和华南地区复合型干旱事件频次, 持续时间和严重程度增加, 而华北和东北地区则减少. 复合型干旱事件的人口暴露度在长江流域南部大幅增加, 在长江流域以北的东部大幅减少, 其中气候和人口均对人口暴露度的变化有重要影响. 由于GDP的快速增长, 中国未来几乎所有地区复合型干旱事件的GDP暴露度增加, 特别是在中国东部, GDP效应对GDP暴露度变化的相对贡献最大.