Effects of anthropogenic climate change on the drought characteristics in China: From frequency, duration, intensity, and affected area

The combination of natural forcing and anthropogenic activities affects the global climate system, increasing the frequency of extreme drought events. Drought events with multi-characteristics will have incalculable impacts on ecology, human life, and socioeconomics. However, the quantitative impacts of climate change caused by anthropogenic forcing on the droughts over China remains unclear. In this study, ensemble mean data of seven global climate models from Coupled Model Intercomparison Project Phase 6 models (CMIP6) under both natural and anthropogenic forcing experiment and only natural forcing experiment (abbreviated as “ALL” and “NAT”, respectively) were used. The drought characteristics are identified by applying the Standardized Precipitation Evapotranspiration Index (SPEI) and run theory. The quantitative impacts of anthropogenic climate change (ACC) on drought frequency, duration, intensity, affected area over China in the past 54 years (1961–2014) were investigated by comparing the drought characteristics between “NAT” and “ALL”. On the whole region, ACC presented anabatic effects on drought such as increasing the frequency, enhancing the intensity, and prolonging the duration. It also increased the area affected by moderate and extreme drought events. ACC was averagely about 1.47 times more determinative of whether a drought event occurs. However, the effect of ACC on drought characteristics did not show spatial consistency: drought in Southwest China was showing a significant aggravation trend influenced by ACC, while droughts in Northwest China were presenting a mitigation tendency. These associated findings emphasize the regional features of drought affected by ACC, and could help policy makers to develop mitigation measures.