Changing rainfall patterns may be depleting India’s groundwater storage more than withdrawals for agricultural irrigation, says a new study published in January by Nature Goescience. While the diminishing of India’s groundwater is widely attributed to over-extraction, especially in the northern agricultural belts of Punjab and Haryana, this study suggests decline in rainfall caused by rise in the temperatures in the Indian Ocean — a major factor in monsoonal rainfall patterns over the Indo-Gangetic Plain — to be a more important cause.
“This study adds another dimension to the existing water management framework. We need to consider not just the withdrawals but also the inputs to the system,” says Yoshihide Wada, co-author of the study and deputy director, Water Programme, International Institute for Applied Systems Analysis, Austria. Importantly, the study finds links between the rise in sea surface temperatures of the Indian Ocean and the declining monsoonal rainfall which co-author Vimal Mishra says may be linked to climate change, though this is yet to be proven.