Global Increases in Compound Flood‐Hot Extreme Hazards Under Climate Warming. Issue 8 (23rd April 2022)

• Record Type: Journal Article
• Authors: Gu, Lei; Chen, Jie; Yin, Jiabo; Slater, Louise J.; Wang, Hui‐Min; Guo, Qiang; Feng, Maoyuan; Qin, Hui; Zhao, Tongtiegang
• Is Part Of: Geophysical research letters. Volume 49:Issue 8(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-04-23
• Subjects: Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2022GL097726
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Under global warming, a novel category of extreme events has become increasingly apparent, where flood and hot extremes occur in rapid succession, causing significant damages to infrastructure and ecosystems. However, these bivariate compound flood‐hot extreme (CFH) hazards have not been comprehensively examined at the global scale, and their evolution under climate warming remains unstudied. Here, we present the first global picture of projected changes in CFH hazards by using a cascade modeling chain of CMIP6 models, satellite and reanalysis data sets, bias correction, and hydrological models. We find an increasing percentage of floods will be accompanied by hot extremes under climate change; the joint return periods of CFHs are projected to decrease globally, particularly in the tropics. These decreasing joint return periods are largely driven by changes in hot extremes and indicate a likely increase of CFH hazards, and ultimately highlight the urgent need to conduct adaptation planning for future risks. Plain Language Summary: Climate change alters the Earth's energy budget and accelerates the hydrological cycle, bringing new hazards such as temporally compounding flood and hot extremes. Rapid transitions from devastating floods to deadly heat, or vice versa, which used to be rare, are already occurring under the present climate and bring new threats to infrastructure and the public. However, these bivariate CFH hazards have been poorly understood at the global scale, and their future evolution in the context of climate change has not yet been assessed. Here, we provide the first systematic assessment of projected changes and attributions in the multivariate hazards of global flood‐hot extremes. We find that the fraction of flooding accompanied by hot extremes could rise markedly under global warming. Changes in hot extremes dominate the exacerbation of global CFH hazards, especially in tropical climate zones. Our study identifies the tropics as the new global hotspot of flood‐hot extreme events in a warming future, and reveals an increasing global risk of unexpected sequential wet‐hot extremes, highlighting the need to better prepare adaptation and mitigation solutions. Key Points: We present the first global assessment of projected changes in compound river flood‐hot extremes Future flood‐hot extremes are mainly driven by changes in hot extremes Substantial increases in compound flood‐hot extremes are projected in tropical regions