Humankind’s collective thirst is slowly desiccating landscapes worldwide, a study of groundwater finds.
Water stored in aquifers underground makes up the vast majority of accessible freshwater on Earth. Its abundance has fueled forays into drier locales, such as California’s Central Valley, enabling a boom in crop production (SN: 7/23/19). And overall, about 70 percent of the groundwater being used worldwide goes to agriculture. But surface waters — rivers and streams — rely on groundwater, too. When people pump too much too quickly, natural waterways begin to empty, compromising freshwater ecosystems.
A study in the Oct. 3 Nature finds that this ecological tipping point, what scientists call the environmental flow limit, has already been reached in 15 to 21 percent of watersheds tapped by humans. Most of those rivers and streams are in drier regions like parts of Mexico and northern India where groundwater is used for irrigation.
If pumping continues at current rates, the authors estimate that by 2050, anywhere from 42 to 79 percent of pumped watersheds will have crossed this threshold. (This is trail post for this site and taken from sciencenews.org)