Preprints
https://doi.org/10.5194/egusphere-2025-4289
https://doi.org/10.5194/egusphere-2025-4289
01 Oct 2025
 | 01 Oct 2025
Status: this preprint is open for discussion and under review for Hydrology and Earth System Sciences (HESS).

Global escalation of more frequent and intense compound heatwave-extreme precipitation events

Haoyu Jin, Ke Zhang, Moyang Liu, Xuan Yu, Xu Yang, Lijun Chao, Pengfei Zhang, and Guoyan Liu

Abstract. Compound heatwave-extreme precipitation (CHWEP) events, the rapid succession of heatwaves and extreme precipitation, pose growing compound and cascading risks. However, global-scale comparisons of their spatiotemporal evolution against single extremes remain limited. This study systematically examines the changes in CHWEP and corresponding single extremes from 1980 to 2100 using climate observations and projections under SSP (Shared Socioeconomic Pathway) 2–4.5 and SSP5-8.5 scenarios. We find that CHWEP exhibit higher frequency, stronger precipitation, and longer heatwave duration in mid-to-high latitudes, while tropical CHWEP feature more intense heatwaves than single heatwave events. These spatial contrasts persist in future projections. Under both scenarios, CHWEP and single extreme metrics intensify globally by 2056–2100, with post-heatwave precipitation exceeding that of single precipitation extremes, particularly under SSP5-8.5, highlighting sensitivity to greenhouse forcing. Critically, the co-occurrence is non-random, indicating an emerging physical linkage. In the tropics, the likelihood of extreme rainfall following heatwaves increases markedly. Our findings demonstrate that CHWEPs are evolving into a distinct, intensifying hazard class, necessitating their integration into climate resilience, early warning, and adaptation frameworks.

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Haoyu Jin, Ke Zhang, Moyang Liu, Xuan Yu, Xu Yang, Lijun Chao, Pengfei Zhang, and Guoyan Liu

Status: open (until 12 Nov 2025)

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Haoyu Jin, Ke Zhang, Moyang Liu, Xuan Yu, Xu Yang, Lijun Chao, Pengfei Zhang, and Guoyan Liu
Haoyu Jin, Ke Zhang, Moyang Liu, Xuan Yu, Xu Yang, Lijun Chao, Pengfei Zhang, and Guoyan Liu
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Latest update: 01 Oct 2025
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Short summary
Heatwaves and heavy rainfall are dangerous on their own. But when they occur in quick succession, extreme heat followed by intense rain, they can create even greater risks. Our findings show that compound heatwave-extreme precipitation events are becoming a distinct and worsening type of climate hazard. They can no longer be treated as isolated events. To build resilience, early warning systems, disaster planning, and adaptation strategies must now account for these compound risks.
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