Increasing Population and Cropland Exposure to Human-Induced Sequential Heatwave-Downpour Events

Abstract

Compound sequential heatwave-downpour (SHD) events, characterized by abrupt shifts from heatwaves to heavy rainfall, pose serious threats to health, infrastructure, and agriculture. However, the anthropogenic influence on the increasing trend of SHD events is poorly understood, and projections also exhibit large uncertainties. Our study revealed that the affected area of SHD events has grown notably across the Northern Hemisphere. The anthropogenic influences account for approximately 82.2% of the increase in affected areas of SHD events, with greenhouse gas emissions contributing the most. The constrained projection found that the exposure of population and cropland will increase nearly 8-fold under a high-emission scenario in the long term (2081–2100), compared to the current climate baseline (1991–2020). Notably, climate change, rather than population or land use change, is identified as the dominant driver of this increased exposure. Our finding highlights that reducing greenhouse gas emissions can mitigate the impacts of SHD on populations and croplands.