600M Rely on River Facing Unprecedented Drying

Once mighty and life-giving, India's Ganges River is facing its worst crisis in over a millennium, with human activity at the heart of the problem. A new study finds the river, relied on by about 600 million people, is drying up faster than at any point in the past 1,300 years. Researchers from IIT Gandhinagar and the University of Arizona used a mix of tree-ring data, historical records, and hydrological models to reconstruct the river's flow since 700 CE, per a release. Their analysis, published in Proceedings of the National Academy of Sciences, shows the period from 1991 to 2020 was 76% drier than the worst previous drought in the 16th century.

The team credits the current crisis primarily to human actions. While natural climate cycles do play a role, the main factors are weakening summer monsoons, which they tie to Indian Ocean warming and air pollution from human-generated aerosols like those from cars and factories. But there are other factors, including water diversions, groundwater pumping, and a retreating glacier at the river's source, per the Conversation. These changes have made droughts along the Ganges not only more severe, but also more frequent and longer-lasting, according to the study.

"The recent drying is well beyond the realm of last millennium climate variability, and most global climate models fail to capture it," wrote the researchers, calling for improvements to climate modeling, specifically to better represent how human activity affects regional water cycles. Given the Ganges' central role in drinking water, agriculture, and industry, the study's authors also urge the adoption of new water management strategies to address the heightened risk of water shortages. They argue that without better planning and more accurate atmospheric models, the region could face an even drier future.