Groundwater depletion has been accelerating in north India for the past 70 years and will continue in the projected future climate, according to a study published in Earth’s Future. The image is used for representative purposes only.
| Photo Credit: FARUQUI AM
Groundwater in north India remains a vital food and water security resource for more than one billion people. But, the summer monsoon drying, and winter warming pose considerable challenges for rapidly declining groundwater, says a new research study.
The study in which scientists of the CSIR-National Geophysical Research Institute (NGRI) in Hyderabad/ Northeast Institute of Science and Technology (NEIST-Jorhat (Assam)) participated along with Indian Institute of Technology (IIT) Gandhinagar, Columbia University, New York (US) and King Abdullah University of Science and Technology, Thuwal, (Saudi Arabia) showed that groundwater depletion has been accelerating in this region for the past 70 years and will continue in the projected future .The study got published in the latest edition of ‘Earth’s Future’, a leading journal of American Geophysical Union.
First-of-its-kind study
Scientists, including former NGRI director and now director of NEIST V.M. Tiwari, Vimal Mishra, Swarup Dangar, Upamanu Lall, Yoshihide Wada have made the first-of-its-kind study exploring the impact on irrigation water demands and groundwater storage using in situ observations, satellite data, and a hydrological model.
Rapid groundwater depletion in north India
Their study indicated that summer monsoon precipitation has reduced and winters have become warmer in north India during 1951–2021. Both satellite and hydrological model‐based estimates show a rapid groundwater depletion (more than 1.5 cm/year) in north India with a net loss of 450 km3 of groundwater during 2002–2021.
Reasons for further depletion of ground water
Reduced groundwater recharge and enhanced pumping to meet irrigation demands has depleted the groundwater further. For instance, the summer monsoon drying (10%–15% deficit for near far periods)followed by substantial winter warming (1–4°C rise in temperatures) in the future will further accelerate groundwater depletion by increasing (6%–20%) irrigation water demands and reducing groundwater recharge (6%–12%), said Dr. Tiwari, in an exclusive interaction.
This phenomena has led to major drought conditions, resulting in a massive loss of groundwater between 2002 and 2021. Examining the response of India’s groundwater to the warming climate is critical for climate adaptation and ensuring food and freshwater security as it leads to increased irrigation water demands in the monsoon (Kharif) and winter (Rabi) seasons, he said.
Current cropping intensity estimated to decline by 68%
A wetter and warmer climate is also projected in north India in the future. The summer monsoon precipitation is estimated to rise by about 9 per cent at a regional warming of 3°C. This will cause a 6% rise in annual irrigation water demands. It is also estimated that current cropping intensity could decline by 68% due to groundwater depletion, explained the top scientist.
Methods to reduce burden on groundwater for irrigation
Scientists suggest that burden on groundwater for irrigation can be reduced by shifting the geographies where crops are procured from and grown without compromising the procurement targets and farm income. Groundwater sustainability measures combined with technological advancements to improve irrigation water use efficiency, altered cropping patterns, and enhanced groundwater recharge would be required to reduce the adverse impacts of groundwater depletion in north India in the future, they added.
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