The spatial distribution characteristics of a comprehensive drought risk index in southwestern China and underlying causes

Drought is a serious problem in southwestern China, where drought risk exceeds the national average. Climate change is likely to exacerbate the problem, thereby endangering China’s food security. In this paper, we used the analytic hierarchy process and meteorological, geographic, soil, and remote-sensing data to develop a drought risk assessment model based on the drought hazard, environmental vulnerability, sensitivity and exposure of the values at risk, and capacity to prevent or mitigate the problem. Using the model, we assessed the drought risk (defined using a comprehensive drought risk index, R) and its spatial distribution in southwestern China and revealed complex zonality. The eastern part of the study area had an extremely high risk, and risk was generally greater in the north than in the south, and increased from southwest to northeast. The comprehensive risk (R) was lowest in Yunnan province. It was highest in Sichuan Province and Chongqing Municipality. The contribution of the risk factors to R was highest for the capacity for prevention and mitigation, followed by the drought hazard, sensitivity and exposure, and environmental vulnerability.