Scientists warn of looming water crisis with millions of wells at risk

Groundwater cached below the Earth’s surface is one of the world’s most precious resources. Nearly half of the human population depends on these reserves for our daily needs and for agriculture. But up to a fifth of wells worldwide that tap into these reserves are at risk of running drying, a recent study in Science has found. A related commentary published in the same journal called the new paper “a timely warning that universal access to groundwater is fundamentally at risk.” The researchers analyzed 39 million wells in 40 countries and territories. By looking at locations, purposes and construction records, they estimated that between 6 and 20% of the wells were no deeper than 5 meters (16 feet) from the groundwater level. If the water table dips by even a few meters, the study authors warn, these wells would run dry. They also found that wells constructed more recently also bore some meters below the current groundwater level. In areas where groundwater is depleting quickly, such wells will not be an alternative to shallower ones for long. Despite its importance, we still don’t really know how much groundwater there is and how the reserves fluctuate. All the signs point to a looming crisis. Groundwater levels can fall because of overextraction, inadequate replenishment, or a combination of factors. A changing climate is a significant threat to groundwater resources because droughts and uneven rainfall can diminish local aquifers. It’s already happening across the globe, from India to the U.S. A 2020 Nature Communications…This article was originally published on Mongabay

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