A new University of Michigan-led study finds that farmers in India have adapted to warming temperatures by intensifying the withdrawal of groundwater used for irrigation. If the trend continues, the rate of groundwater loss could triple by 2080, further threatening India's food and water security.
Reduced water availability in India due to groundwater depletion and climate change could threaten the livelihoods of more than one-third of the country's 1.4 billion residents and has global implications. India recently overtook China to become the world's most populous nation and is the second-largest global producer of common cereal grains including rice and wheat.
"We find that farmers are already increasing irrigation use in response to warming temperatures, an adaptation strategy that has not been accounted for in previous projections of groundwater depletion in India," said study senior author Meha Jain, assistant professor at U-M's School for Environment and Sustainability. "This is of concern, given that India is the world's largest consumer of groundwater and is a critical resource for the regional and global food supply."
The lead author is Nishan Bhattarai of the Department of Geography and Environmental Sustainability at the University of Oklahoma, formerly a postdoctoral researcher in Jain's U-M lab. The study analyzed historical data on groundwater levels, climate and crop water stress to look for recent changes in withdrawal rates due to warming. The researchers also used temperature and precipitation projections from 10 climate models to estimate future rates of groundwater loss across India.
The new study takes into account the fact that warmer temperatures may increase water demand from stressed crops, which in turn may lead to increased irrigation by farmers. "Using our model estimates, we project that under a business-as-usual scenario, warming temperatures may triple groundwater depletion rates in the future and expand groundwater depletion hotspots to include south and central India. Without policies and interventions to conserve groundwater, we find that warming temperatures will likely amplify India's already existing groundwater depletion problem, further challenging India's food and water security in the face of climate change," Bhattarai said.
In addition to Jain and Bhattarai, the authors of the Science Advances study are David Lobell of Stanford University, Balwinder Singh of the International Maize and Wheat Improvement Center in India and the Department of Primary Industries and Regional Development in Western Australia, Ram Fishman of Tel Aviv University, William Kustas of the U.S. Department of Agriculture and Yadu Pokhrel of Michigan State University.
The research was funded by a NASA Land-Cover Land-Use Change Grant and a NASA new investigator program award to Jain. It was supported in part by the U.S. Department of Agriculture's Agricultural Research Service.
.png)
