Intensifying floods are emerging as a major and rapidly growing threat to global rice production, placing food security for billions of people at serious risk. New research from Stanford University shows that prolonged flooding is wiping out millions of tonnes of rice every year, with the damage accelerating as climate change fuels heavier rainfall across key agricultural regions.
Published in the journal Science Advances the study finds that global rice yields declined by an average of 4.3 per cent annually between 1980 and 2015, translating to nearly 18 million tonnes of lost grain each year. Since 2000, the pace of losses has increased as extreme flood events have become more frequent and intense.
Flooding emerges as an overlooked threat to rice production
Rice has long been associated with water-intensive farming, leading to a widespread assumption that flooding poses little risk to the crop. However, scientists say this belief is dangerously misleading. While shallow water supports rice growth in its early stages, extended or deep flooding can quickly overwhelm and kill the plants.
The research confirms that droughts remain highly destructive, reducing annual rice yields by an average of 8.1 per cent over the 35-year study period. But it also highlights flooding as a parallel and underappreciated hazard that is now causing comparable damage in many rice-growing regions.
Steven Gorelick, senior author of the study and professor of Earth system science at Stanford University, said the impacts of flooding on rice have received far less attention than drought. He noted that the study not only maps where rice yields have already suffered due to floods, but also identifies areas where future losses are most likely.
A critical threshold that turns floods deadly for rice
The researchers identified a clear tipping point at which flooding becomes fatal for rice crops. When rice plants remain fully submerged for seven consecutive days during the growing season, most do not survive.
Lead author Zhi Li, now a faculty member at the University of Colorado Boulder, explained that defining these “rice-killing floods” allowed scientists to quantify their destructive impact for the first time. By focusing on this threshold, the team was able to link specific flood events directly to yield losses across the globe.
To reach their conclusions, the researchers combined global rice yield records, historical drought and flood data dating back to 1950, flood dynamics modelling, soil moisture simulations and information on rice growth stages across major river basins.
Climate change intensifying rainfall extremes
The analysis shows that extreme rainfall events are becoming stronger and more damaging. In many of the world’s key rice-growing regions, the most intense week of rainfall is expected to bring around 13 per cent more precipitation in coming decades compared to the historical average between 1980 and 2015.
Scientists warn that climate change is likely to intensify this trend, increasing the frequency and severity of rice-killing floods unless emissions are sharply reduced.
High-risk regions identified in the study include India’s Sabarmati Basin, which experiences some of the longest flood durations lethal to rice, as well as North Korea, Indonesia, China, the Philippines and Nepal. The greatest total production losses have been recorded in North Korea, eastern China and West Bengal in India.
Exceptions offer insight into resilience
Not all regions respond to flooding in the same way. In India’s Pennar Basin, for example, flooding has been linked to higher rice yields rather than losses. Researchers suggest that the region’s hot and dry climate allows floodwaters to evaporate quickly, preventing prolonged submergence that would otherwise damage crops.
These exceptions, scientists say, highlight the importance of local climate conditions in determining how rice responds to extreme weather.
Flood-resistant rice could reduce future losses
The study points to flood-tolerant rice varieties as one of the most promising tools for reducing crop losses in vulnerable regions. Expanding their use, especially in flood-prone basins, could help farmers adapt to increasingly volatile weather patterns.
However, researchers stress that breeding and deploying resilient crops must go hand in hand with broader climate adaptation strategies. Rapid shifts between drought and flooding, a pattern becoming more common under climate change, can cause nearly double the damage seen from either stress alone.
A growing challenge for global food security
Rice feeds more than half of the world’s population, making its vulnerability to climate extremes a global concern. The findings underscore how climate change is reshaping agricultural risks in complex and compounding ways.
“How rice responds to multiple climate stresses, both individually and in sequence, remains a major challenge,” the authors noted. Without urgent action to address climate change and strengthen agricultural resilience, the world’s most important staple crop may face increasingly frequent and severe losses.