This study is led by Yitong Zhang and Zengchao Hao from the College of Water Sciences, Beijing Normal University. Research on the hot drought variability generally paid attention to a specific timescale relevant to its impacts, leaving a comprehensive understanding of changes across timescales lacking. This study identified regional and global changes in hot droughts at different timescales, including observed changes and attribution to human influence, as well as projected changes, based on the ERA5 reanalysis product and model simulations from the Coupled Model Intercomparison Project Phase 6 (CMIP6).
An increase in the frequency and spatial extent of hot droughts for weekly, monthly, seasonal, and annual scales was observed in historical periods. A pronounced shift in the trend of spatial extent became evident after the 1990s. At the regional scale, increased changes in the frequency and upward trends of spatial extents were observed across most of the 26 IPCC SREX regions. Comparisons of changes in the frequency and spatial extent from ERA5, CMIP6 all-forcing (ALL), and CMIP6 natural forcing (NAT) simulations from 1951 to 2014 indicated that anthropogenic factors played a significant role in driving the observed increases in hot droughts. Increased frequency and spatial extent of hot droughts across multiple timescales were projected under the SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios in the future period 2015–2100. A higher frequency of hot droughts was projected at northern South America, southern Africa, and Europe, across different timescales for the future period 2037–2100, with certain high latitude regions displaying decreased frequency at the annual timescale.
This study revealed the emerging pattern that warmer and drier weeks, months, seasons, and years are likely to become the norm in a changing climate. In tandem with improved efforts on impact and risk assessments of hot droughts, this study provides useful information for the implementation of tailored adaptation measures to mitigate the negative impacts of hot droughts across timescales.
See the article:
Zhang Y, Hao Z, Chen Y, Pang Y, Singh V P. 2025. Increases in global hot droughts across multiple timescales. Science China Earth Sciences, 68(10):3189–3199, https://doi.org/10.1007/s11430-024-1680-4
Journal
Science China Earth Sciences