Future changes in extreme precipitation from 1.0 °C more warming in the Tienshan Mountains, Central Asia

Abstract

The Tienshan Mountains is the main water source and ecological barrier in the central portion of the Silk Road Economic Belt, a new economic development zone with the Asia-Pacific Economic Circle to the east and the European Economic Circle to the west. Production-living-ecological activities in the arid Central Asia region are heavily dependent on water resources mainly recharged from melt and alpine precipitation. Hence, reliable projections of changes in extreme precipitation under global warming are particularly important for the utilization and management of water resources. Based on the downscaled and bias-corrected state-of-art global climate models from the Coupled Model Intercomparison Project Phase 6 (CMIP6), we investigate changes in extreme precipitation over the Tienshan Mountains, Central Asia (TMCA) under different levels of global warming (1.5 °C, 2.0 °C, 3.0 °C, and 4.0 °C). We specifically assess the robustness of changes and the benefits of limiting warming to 2.0 °C as opposed to 3.0 °C. Compared with the reference period (1976–2005), a robust change in extreme precipitation across the TMCA is expected for all warming levels. And the fraction of land faced a robust change also increases with warming levels. Furthermore, there would be a substantial rise in extreme impacts in the TMCA when shifting from increases of 2.0 °C to 3.0 °C. In a scenario involving a 1.0 °C rise (i.e., from 2.0 °C to 3.0 °C), nearly 85.70 % and 60.19 % of the land in the TMCA will be affected by a robust increase in annual total wet-day precipitation (PRCPTOT) and number of light rain days (R5mm), respectively. In the same scenario, areas affected by robust changes in duration indices (consecutive dry days [CDD] and consecutive wet days [CWD]) will likely be less than 11.59 %. Limiting warming to 2.0 °C instead of 3.0 °C can avoid a marked increased impacts of about 62.84 %∼153.77 % of the change in frequency, intensity, and duration of extreme precipitation.