Characteristics of Climate Change in Xizang Plateau from 1980 to 2023 and Its Impact on Agriculture

Based on the observation data of temperature, precipitation and sunshine hours of 38 meteorological stations in Xizang from 1980 to 2023, the spatial-temporal variation characteristics of key climatic elements were analyzed by using linear regression, five-year moving average, Mann-Kendall (M-K) mutation test and other methods. The results show that: (1) In the past 44 years, the average annual temperature in Xizang has risen very significantly at a rate of 0.379 ℃/10 a, with a sudden climate change in 2000 and a significant warming turning point in 1997. Spatially, the warming rate in the northwest high-altitude areas (Naqu, Ali) is higher than that in the southeast, and the crop suitable areas are expanding towards higher altitudes. (2) The annual precipitation showed a weak increasing trend (4.032 mm/10 a) and underwent a sudden change in 1985. After 2009, the precipitation showed a decreasing trend. The spatial variability of precipitation is significant, with the southeast (Linzhi) reaching 2.8 times that of the northwest (Ali). In terms of seasons, it shows a "warm wet cold dry" pattern of increasing humidity in spring and summer, and drying in autumn and winter, with a trend of precipitation concentration (the contribution rate from May to September increases to 59%), and extreme precipitation events occur frequently. (3) The sunshine hours significantly decreased by 21.2 hours per 10 years, and underwent a sudden change in 2016. The spatial distribution and precipitation changed in reverse, with a significant difference between the“ less rain and more sunshine” in the arid northwest region and the“ more rain and less sunshine” in the humid southeast region. There is a slight increase in winter season and a significant decrease in summer season. Climate change has had a two-way effect on Xizang’s agriculture: warming significantly prolonged the growth season, expanded high-altitude habitat, and slightly improved the light and heat efficiency of winter facilities. However, the differentiation and concentration of precipitation space have intensified the risks of floods in the southeast and droughts in the northwest. The decrease in sunshine may affect photosynthetic efficiency and significantly increase the frequency, scope, and threat of extreme events of pests and diseases. The increase in winter sunshine is conducive to the development of facility agriculture and can provide theoretical and scientific basis for optimizing regional agricultural layout, disaster prevention, and sustainable development.