Indian farmers are adapting to rising temperatures by significantly increasing their use of groundwater for irrigation. This adaptation, if continued, could lead to a tripling of groundwater depletion rates by 2080, posing severe threats to India’s food and water security, according to a recent study.
India, which recently surpassed China as the world’s most populous nation, is also the second-largest global producer of essential cereal grains like rice and wheat. However, reduced water availability due to groundwater depletion and climate change has the potential to jeopardize the livelihoods of more than one-third of India’s 1.4 billion residents and has global implications.
The study, published in the journal Science Advances, analyzed historical data on groundwater levels, climate conditions, and crop water stress to identify changes in withdrawal rates caused by warming temperatures. It also utilized climate models to estimate future rates of groundwater loss across India.
Unlike previous research that solely examined the impacts of climate change and groundwater depletion on crop production, this study considered farmer decision-making. It recognized that warmer temperatures can lead to increased water demand from crops experiencing stress, resulting in farmers using more irrigation.
The findings suggest that if current trends persist, warming temperatures could triple groundwater depletion rates in the future, extending depletion hotspots to include south and central India. The study underscores the urgent need for policies and interventions to conserve groundwater to address India’s existing depletion problem and ensure food and water security in the face of climate change.
Previous studies have already warned that climate change could reduce staple crop yields in India by up to 20% by mid-century. Simultaneously, groundwater is being rapidly depleted due to irrigation demands.
To conduct the study, researchers compiled a dataset that included groundwater depth measurements from thousands of wells across India, high-resolution satellite data indicating crop water stress, and records of temperature and precipitation.
Most climate models predict increased temperatures, rising monsoon precipitation (from June through September), and decreased winter precipitation in India in the coming decades. The research team discovered that warming temperatures, combined with declining winter precipitation, offset the increased groundwater recharge from the monsoon rains, leading to accelerated groundwater depletion.
Across various climate change scenarios, the estimates for the level decline between 2041 and 2080 were more than three times the current depletion rates, on average.
The study’s authors include researchers from Stanford University, the International Maize and Wheat Improvement Center, Tel Aviv University, the U.S. Department of Agriculture, and Michigan State University.