Flash floods: why are more of them devastating the world’s driest regions?

Author:IMBeR IPO Date:2023-03-29 Hits:57


Flash floods: why are more of them devastating the world's driest regions?

作者:Jie Yin, Yao Gao, Ruishan Chen, Dapeng Yu, Robert Wilby, Nigel Wright, Yong Ge, Jeremy Bricker, Huili Gong & Mingfu Guan



In 2022, around two-thirds of Pakistan was affected by widespread flash flooding, with more than 1,500 people killed and around 33 million made homeless. Almost 2,000 people died in flash floods across Africa, and parts of the United Arab Emirates, Iran, Saudi Arabia, Qatar, Oman and Yemen were inundated with water. On August 18th, a flash flood in Datong town in Qinghai province, China, washed away more than 1,500 homes and killed dozens of people in less than one hour.


Flash floods are a growing threat in the world’s arid or semi-arid regions, causing heavy casualties and economic losses. Our analysis using the Emergency Events Database (EM-DAT; www.emdat.be) shows that, since 2000, such regions experienced less than half (47%) of deadly flash floods globally, yet saw almost three-quarters (74%) of related deaths (see ‘Global flash-flood disasters’). The majority of these floods (87%) and associated deaths (97%) occurred in low- and middle-income countries.


The increased impact of climate change and human activities is making such events more intense and frequent. Climate change has led to a significant “warming-wetting” trend in the arid and semi-arid regions worldwide, with the 5-day maximum level of rainfall about 8% higher in the 2010s than in the 1980s. In parts of Pakistan, the 5-day maximum level of rainfall is 75% greater today than it was before 1900 (see go.nature.com/41awzzj). By our calculation, more people are living in drylands, and cities in such areas are expanding rapidly. Yet only 1% of those people are living in developed countries. And the proportion of the world’s land area classed as arid or semi-arid is projected to increase as the world warms.


Researchers, practitioners and policymakers need to model, assess and mitigate the risk of flash flooding in drylands in a changing environment. Here, we set out six research priorities for doing so.

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Source: EM-DAT, CRED/UC Louvain (www.emdat.be); Analysis by J. Yin et al.