Escalating risks of anomalously hot–dry growing seasons in arid Northwest China under human influence

The anomalous hydrothermal conditions during growing seasons, i.e. less precipitation and high temperature, could induce an unstable water resource supply and pose great threats to regional agro-pastoral production, particularly in water-scarce drylands. Owing to the biases in the simulations of global climate models, quantifying the anthropogenic influences on such high-impact hot–dry extremes and future risks in the arid and semi-arid areas remains challenging. Based on CN05.1 observations and statistically downscaled simulations from the Coupled Model Intercomparison Project Phase 6, we conducted a comprehensive attribution and projection on the 2022- and 2023-like growing-season hot–dry extremes in Northwest China (NWC). Observations reveal that NWC experienced a fourfold increase in the occurrence of anomalously hot–dry growing seasons during 1991–2023 relative to that in 1961–1990. Attribution indicates that anthropogenic forcings have doubled/tripled the likelihood of 2022/2023-like hot–dry growing seasons in NWC largely due to human-induced warming. NWC is expected to experience increasingly hot growing seasons but with slight precipitation changes in the 21st century under the intermediate greenhouse gas emission (SSP2-4.5) scenario. The likelihood of 2022/2023-like hot–dry growing seasons in NWC will be more than 1–5 times that in the present-day (1991–2020), which is still dominated by rising temperature. To alleviate the stress of hot–dry growing seasons on agro-pastoral systems, we underscore the urgency of developing effective adaptation and mitigation strategies for water resource management in water-limited drylands.