Threat of low-frequency high-intensity floods to global cropland and crop yields

Abstract

Flood hazards pose a significant threat to agricultural production. Agricultural adaptations tend to be prevalent and systematic in high-frequency flood (HFF) areas but neglected in low-frequency flood (LFF) areas. Here, using satellite imagery, we map global spatial distributions of LFF and HFF at 250 m resolution for 3,427 flood events between 2000 and 2021. We show that LFF affected a larger proportion of cropland area (4.7%) than HFF (1.2%), and HFF occurred in smaller regions with less intensity. Cropland expansion between 2000 and 2019 increased the area affected by LFF (3.1 × 104 km2) more than that affected by HFF (1.3 × 104 km2). Moreover, the mean yield losses of wheat and rice from LFF were greater than those from HFF, owing to the higher precipitation anomalies, soil moisture anomalies and greater crop flooding during their growing seasons. Our findings highlight the urgency of this issue and identify priority areas to prevent these neglected low-frequency but high-impact floods, providing valuable information for developing flood-adapted policy. Mitigation efforts to protect agricultural productivity against flooding focus on areas with high-frequency floods. However, agricultural regions with low-frequency floods experience a larger proportion of flood impacts, highlighting the urgency of prioritizing mitigation efforts in these regions.