California isn't the only place where water is in short supply. More than a third of the world's groundwater basins are distressed, according to a new study, and climate change and a growing population will only make things worse.
Researchers from NASA, the University of California, Irvine, and other institutions analyzed satellite data and found that eight out of 37 of Earth's largest aquifers were "overstressed" or "extremly or highly stressed," meaning they had no natural replenishment or very little, respectively.
The most overstressed groundwater supply in the world: the Arabian Aquifer System, which provides water for 60 million people. The second and third most-stressed aquifers were located in Pakistan and northern Africa.
The study was published Tuesday in the journal Water Resources Research.
"What happens when a highly stressed aquifer is located in a region with socioeconomic or political tensions that can't supplement declining water supplies fast enough?" asked Alexandra Richey, the UCI researcher who led the study. "We’re trying to raise red flags now to pinpoint where active management today could protect future lives and livelihoods."
Richey led a companion study published in the same journal that found that while researchers could tell if aquifers were stressed, judging exactly how much water remains in them is extremely difficult, with estimates ranging from decades to thousands of years.