Attribution of the Extreme Drought Event over the Yangtze River Valley in China

Global warming has led to the intensification and increased frequency of drought events. Determining the extent to which these events are influenced by human activities is critical for developing effective strategies to address climate change. However, detecting human impacts and providing robust attribution results remain key challenges in drought research. In the summer of 2022, the Yangtze River Valley of China experienced an unprecedented extreme drought, marked by record-high surface temperatures and record-low precipitation over the past 60 years. This event caused substantial socio-economic and ecological disruptions. To assess the role of anthropogenic climate change in the intensity and frequency of such events, this study established an attribution framework based on GAMIL3.0. This study evaluated anomalies in surface temperature, precipitation, and large-scale circulation patterns during the summer of 2022. Results indicate that human activities have intensified the Western North Pacific Subtropical High and South Asian High, increasing their strength and frequency and thereby amplifying the intensity and likelihood of extreme drought events in the Yangtze River Valley. Anthropogenic forcing contributed to an additional 0.8°C rise in surface temperature (95% confidence interval: 0.1–1.5°C) and a 7.9% reduction in precipitation (-24.1% to 7.8%) during the 2022 summer. The anthropogenic forcing increased the probability of surface temperature anomalies associated with such an extreme drought event like 2022 by 1300 times (range: 87–3,001) and precipitation anomalies by 65 times (range: 1–90). This study highlights the urgent need to strengthen adaptive capacities to mitigate the impacts of extreme drought in the Yangtze River Valley.