By J. Garthwaite, Stanford U., Dec. 11, 2025
https://scitechdaily.com/rice-fields-are-drowning-and-the-damage-is-accelerating-worldwide/
https://scitechdaily.com/rice-fields-are-drowning-and-the-damage-is-accelerating-worldwide/
Intensifying floods are rapidly undermining global rice production, putting food security at risk for billions.
Credit: Shutterstock
New research shows that severe flooding is becoming a major and growing threat to global rice production, wiping out millions of tons of grain each year.
Scientists found that even a single week of total submergence can kill most rice plants, a risk that is increasing as extreme rainfall intensifies in key river basins.
Rising Flood Risks for Global Rice Production
Severe flooding has sharply reduced rice harvests worldwide in recent decades, posing serious risks to the billions of people who rely on the grain as a primary food source. Research from Stanford University, published recently in Science Advances, estimates that global rice yields declined by approximately 4.3 percent per year between 1980 and 2015, corresponding to about 18 million tons of lost rice annually.
The study reports that the pace of damage has increased since 2000 as extreme flooding has become more common in many of the world’s major rice-producing regions. The researchers note that climate change is expected to further intensify these destructive events in the years ahead.
Severe flooding has sharply reduced rice harvests worldwide in recent decades, posing serious risks to the billions of people who rely on the grain as a primary food source. Research from Stanford University, published recently in Science Advances, estimates that global rice yields declined by approximately 4.3 percent per year between 1980 and 2015, corresponding to about 18 million tons of lost rice annually.
The study reports that the pace of damage has increased since 2000 as extreme flooding has become more common in many of the world’s major rice-producing regions. The researchers note that climate change is expected to further intensify these destructive events in the years ahead.
Floods and Droughts Create Compounding Threats
Rice producers have long recognized how drought reduces yields. The new analysis confirms this pattern, finding that droughts cut annual rice production by an average of 8.1 percent over the 35-year study period. At the same time, the work calls attention to a different hazard that has received far less scrutiny. While rice grows well in shallow water early in its development, extended or deep flooding can quickly overwhelm the plants.
“While the scientific community has focused on damage to rice yield due to droughts, the impacts of floods have not received enough attention,” said Steven Gorelick, the study’s senior co-author and a professor of Earth system science in the Stanford Doerr School of Sustainability. “Our research documents not only areas where rice yields have suffered due to past flooding, but also where we can anticipate and prepare for this threat in the future.”
Rice producers have long recognized how drought reduces yields. The new analysis confirms this pattern, finding that droughts cut annual rice production by an average of 8.1 percent over the 35-year study period. At the same time, the work calls attention to a different hazard that has received far less scrutiny. While rice grows well in shallow water early in its development, extended or deep flooding can quickly overwhelm the plants.
“While the scientific community has focused on damage to rice yield due to droughts, the impacts of floods have not received enough attention,” said Steven Gorelick, the study’s senior co-author and a professor of Earth system science in the Stanford Doerr School of Sustainability. “Our research documents not only areas where rice yields have suffered due to past flooding, but also where we can anticipate and prepare for this threat in the future.”
Defining the Threshold for ‘Rice-Killing Floods’
Lead study author Zhi Li, who completed the research as a postdoctoral fellow in Gorelick’s lab and is now on the faculty at the University of Colorado Boulder, explained that the team identified a clear threshold that determines when flooding becomes deadly for rice.
A full week of complete submergence during the growing period is the tipping point. “When crops are fully submerged for at least seven days, most rice plants die,” Li said. “By defining ‘rice-killing floods,’ we were able to quantify for the first time how these specific floods are consistently destroying one of the most important staple foods for more than half of the global population.”
To estimate the effects of past droughts and floods on production, the researchers combined information about rice growth stages, annual global yield data, a worldwide database of drought and flood events since 1950, a flood dynamics model, and simulations of soil moisture across major rice-growing basins. Their analysis indicates that in the coming decades, the most intense week of rainfall in these regions may result in approximately 13 percent more precipitation than the historical average for 1980 to 2015.
Lead study author Zhi Li, who completed the research as a postdoctoral fellow in Gorelick’s lab and is now on the faculty at the University of Colorado Boulder, explained that the team identified a clear threshold that determines when flooding becomes deadly for rice.
A full week of complete submergence during the growing period is the tipping point. “When crops are fully submerged for at least seven days, most rice plants die,” Li said. “By defining ‘rice-killing floods,’ we were able to quantify for the first time how these specific floods are consistently destroying one of the most important staple foods for more than half of the global population.”
To estimate the effects of past droughts and floods on production, the researchers combined information about rice growth stages, annual global yield data, a worldwide database of drought and flood events since 1950, a flood dynamics model, and simulations of soil moisture across major rice-growing basins. Their analysis indicates that in the coming decades, the most intense week of rainfall in these regions may result in approximately 13 percent more precipitation than the historical average for 1980 to 2015.
Flood-Resistant Rice Varieties Offer a Path Forward
Expanding the use of flood-resistant rice varieties could help reduce losses, particularly in areas that face the greatest danger from prolonged flooding. The study highlights several high-risk regions, including India’s Sabarmati Basin, which experiences some of the longest rice-killing floods, as well as North Korea, Indonesia, China, the Philippines, and Nepal, where damage from these events has increased most sharply. The largest total losses have occurred in North Korea, East China, and India’s West Bengal.
There are also exceptions. In India’s Pennar Basin, for example, flooding appears to boost rice yields. The authors suggest that the hot, arid climate in this region may help floodwater evaporate quickly enough to prevent long-term damage.
Expanding the use of flood-resistant rice varieties could help reduce losses, particularly in areas that face the greatest danger from prolonged flooding. The study highlights several high-risk regions, including India’s Sabarmati Basin, which experiences some of the longest rice-killing floods, as well as North Korea, Indonesia, China, the Philippines, and Nepal, where damage from these events has increased most sharply. The largest total losses have occurred in North Korea, East China, and India’s West Bengal.
There are also exceptions. In India’s Pennar Basin, for example, flooding appears to boost rice yields. The authors suggest that the hot, arid climate in this region may help floodwater evaporate quickly enough to prevent long-term damage.
Understanding Combined Climate Stresses
For Gorelick and Li, the findings reinforce the need to explore how rice responds to multiple climate stresses, both individually and in succession. Previous research has shown that rapid shifts from drought to flooding and back again can cause nearly twice the yield loss seen from drought or flooding alone. According to the authors, “How these combined effects can be mitigated remains a major challenge.”
For Gorelick and Li, the findings reinforce the need to explore how rice responds to multiple climate stresses, both individually and in succession. Previous research has shown that rapid shifts from drought to flooding and back again can cause nearly twice the yield loss seen from drought or flooding alone. According to the authors, “How these combined effects can be mitigated remains a major challenge.”
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