Hazards of extreme events in China under different global warming targets

Changes in the frequency and intensity of extreme events affect the risk pattern of risk-bearing bodies and the effectiveness of response measures. Based on future climate scenario data, in this study, we identify global warming periods of 1.5 degrees C and 2 degrees C above pre-industrial levels, and the temporal and spatial patterns of temperature and precipitation in China during the same period, propose a methodology for risk assessment and integrated analysis of extreme events, build a database of extreme events and their hazards in China in the context of climate change, and assess the hazards caused by extreme events (i.e., heatwaves, floods, and droughts) in China under different warming periods. Under the RCP4.5 and RCP8.5 scenarios, global temperatures increase by 1.5 degrees C and 2 degrees C above pre-industrial levels by 2029 and 2026 and by 2050 and 2040, respectively. The warming would be fast in the north and slow in the south, the warming of the Qinghai-Tibet Plateau would accelerate, and the precipitation would increase in the north and decrease in the south, but the trend of the precipitation reduction in the south would be more significant under the RCP8.5 scenario. For 2 degrees C of warming, the hazard index of severe heatwaves in the North China Plain, parts of South China, and the western part of Inner Mongolia would double that of 1.5 degrees C warming. Regional differences in extreme precipitation would increase, especially under the RCP8.5 scenario, the hazard index of severe floods in parts of East China would be about twice that of 1.5 degrees C warming. Under the joint influence of rising temperature and changing precipitation, the drought situation would be alleviated under the RCP4.5 scenario, but it is intensified under the RCP8.5 scenario. For 2 degrees C of warming, the hazard index of severe droughts in some areas would reach three times that of 1.5 degrees C warming. For the integrated hazard of the three types of extreme events, the areas of high and medium hazards would expand, while the areas of low hazard would decrease. For 2 degrees C of warming, the areas of high and medium hazards would be more than half the total area.