Study shows accelerating groundwater depletion in north India

The pace of groundwater depletion in north India was mentioned in a study published in ‘Earth’s Future’ magazine, with accelerated depletion projected in the future.

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.

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.

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.

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.

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.