Attribution of the Extreme 2022 Summer Drought along the Yangtze River Valley in China Based on Detection and Attribution System of Chinese Academy of Sciences

The Yangtze River valley was hit by drought in 2022 summer unprecedented since 1961, with record low precipitation and high temperature. It was caused by a combination of enhanced NWPSH and SAH. We used GAMIL3.0 to conduct two large-ensemble simulations for the climate with all external forcing and for a hypothetical natural climate without human influence, to assess the role of human influence on the intensity and probability of 2022-like extreme drought along the YRV. The analysis indicated that human influences tend to amplify the summer WNPSH and SAH in 2022, consequently increasing the intensity and likelihood of extreme drought. Human forcing contributed to a 7.9% (7.8%-24.1%) reduction in precipitation and 0.8°C (0.1°-1.5°C) warming in Tas along the YRV and increased the likelihood of this event from 0.07% (0.05%-4.5%) to 4.8% (3.3%-6.1%) for Pr deficit, and from 0.005% (0.002%-0.07%) to 6.3% (4.9%-9.8%) for Tas, respectively. Thus, the risk has increased by 65 (1-90) times for Pr and 1300 (90-3000) times for Tas in 2022 due to human influence. The higher risk of extreme drought along the YRV due to human influence poses serious challenges for decision-makers and the society in the energy-food-water-ecology nexus to better adapt to increasing drought in the future.