The assessment of hazard changes of high temperature can provide decision basis for regional high temperature risk management and disaster reduction measures. Based on the daily maximum temperature data from 1961 to 2020 and the future climate predictions provided by the 12 climate models in the SSP2-4.5 scenario in the CMIP6 from 2031 to 2099, three indicators were calculated and used to assess the hazard of high temperature, including the number of high temperature days, maximum temperature, and average high temperature intensity. We used the kernel density estimation to calculate the values of the three indicators under four return periods (5, 10, 20, 50 years) of historical and future climate scenarios, and then evaluated the hazard changes of high temperature. The results show that: (1) Under the SSP2.4- 5 scenario, the number of high temperature days in China presented four risk centers, including the central part of the arid (semi-arid) area of Northwest China, the intersection area of North China and Central China, the central part of Southwest China, and the southern part of South China. The number of high temperature days gradually decreased outward from these four centers. The spatial distribution of the maximum temperature in the north China was greater than that in the south China, and this distribution in the east China was greater than that in the west China. The distribution of average high temperature intensity showed a decreasing trend from the southern part of North China, the western part of the arid (semi-arid) region of the Northwest China, and the western part of the eastern region to other regions in China except the Qinghai-Tibet Plateau; (2) Under the scenario of SSP2.4-5, with the increase of the return period, the three high temperature indicators in China all showed an increasing trend. The area affected by high temperature expanded, and the values of the three high temperature indicators increased significantly; (3) The changes of the three high temperature indicators showed obvious spatial aggregation. The hotspot areas jointly displayed by the three indicators were: the northern and southern parts of the Southwest China, the central part of the arid (semi-arid) area of the Northwest China, and a small part of the northern and central parts of China, which were most likely to have high- temperature disasters. The change of high temperature days and maximum temperature indicated that high temperature disasters in the western part of the eastern region may also be large. The cold spot areas shown by the three indicators were: the southeast of the Qinghai- Tibet Plateau, the western part of the arid (semi- arid) northwestern region, the western part of the Tibetan Plateau, and the southeast coastal areas of China. There was little risk of high temperature in these areas. © 2022, Science Press. All right reserved.
