Warming-and-wetting trend over the China's drylands: Observational evidence and future projection

A recent "warming-and-wetting" trend over China's drylands has raised widespread attention in the scientific community. Based on the observations and model projections of temperature and precipitation, this study shows that the warming and regional wetting trend in China's drylands is becoming stronger. Over the past 60 years, the temperature in China's drylands has increased at a rate of 0.34 degrees C/10a, much higher than that in China (0.29 degrees C/10a) and globally (0.22 degrees C/10a). The wetting trend has been primarily apparent in the western part since the 1980s, particularly in the mountainous areas. In the northeast edge of the Qinghai-Tibet Plateau, the wetting rate exceeded 30 mm/10a. The possible cause of the increase of precipitation in China's drylands may be the higher convective precipitation, also concentrating in the mountainous areas. Model projections show weak and strong warming in the future under the RCP2.6 and RCP8.5 scenarios, respectively. Precipitation will increase slightly in the mid-21st century and then decrease slowly until the end of the 21st century under the RCP2.6 scenario. In comparison, under the RCP8.5 scenario, it will increase by 15-25% at the end of the 21st century.