Warm-wetting and/or warm-drying tendency over Xinjiang, China?

Drylands, characterized by fragile ecosystems and severe water shortages, are highly responsive to climatic changes. Recent studies have observed a general wetting trend in Xinjiang, a region covering over one-sixth of China territory and known for its arid climate. However, the spatiotemporal variability of wetting and drying tendencies and their underlying drivers remain poorly understood. Here we utilize the Eulerian moisture tracking model in conjunction with emergent constraining projections to assess trends in moisture dynamics across Xinjiang. Our analysis reveals a prevailing warm-wetting tendency over the past 40 years. We find that moisture influx into Xinjiang predominantly originated from the North Atlantic, traveling through Europe and West Asia, with external sources contributing approximately 89.1 % of the region’s total water vapor. The increased moisture input has driven the observed wetting trend. Constraining projections indicate future increases in precipitation, evaporation, and temperature in Xinjiang, with the rate of change being more pronounced under the SSP585 scenario. Spatially, northern Xinjiang and its mountainous regions exhibit a significant warm-wetting trend, while southern Xinjiang shows a tendency towards warm-drying. Restricting global temperature rises to 1.5 °C above pre-industrial levels, as opposed to 2 °C, could mitigate extreme drying and wetting conditions in the region. These findings underscore the partially wetting trend in drylands and highlight the critical need for stringent climate action to limit global warming to 1.5 °C for effective climate change mitigation.