Severe floods significantly reduce global rice yields.

Rice serves as a staple food for over half of the world's population. Although the reduction of rice yields by droughts is well known, when flooding fully submerges rice plants for over 1 week, crops cannot survive. Considering rice growth stages, using a flood dynamics model and difference-in-differences, we assessed the causal impact of rice crop submergence on yield losses from 1980 to 2015. Globally, these floods reduce annual rice yield by 4.3%, with China's East Coast experiencing 14% losses. Since 2000, yield losses have increased due to more frequent extreme floods, a trend anticipated to continue. Our findings highlight the need for flood-resistant rice cultivars to mitigate risks and support global food security, and implement adaptation strategies against both flood and drought rice yield losses.