At the beginning of November, The New York Times ran the headline, “America is using up its groundwater like there’s no tomorrow.” The journalists from the renowned media outlet had published an investigation into the state of groundwater reserves in the United States. They came to the conclusion that the United States is pumping out too much groundwater.
But the US isn’t an isolated case. “The rest of the world is also squandering groundwater like there’s no tomorrow,” says Hansjörg Seybold, Senior Scientist in the Department of Environmental Systems Science at ETH Zurich. He is coauthor of a study that has just been published in the journal Nature.
Scientific evidence of rapidly depleting water resources
Together with researchers from the University of California, Santa Barbara (UCSB), he has corroborated the journalists’ worrying findings. It is not only in North America that far too much groundwater is being pumped out, but also in other parts of the world where humans have settled.
In an unprecedented feat of painstaking effort, the researchers have compiled and analysed data from over 170,000 groundwater monitoring wells and 1,700 groundwater systems over the past 40 years.
This measurement data shows that in recent decades, humans have massively expanded groundwater extraction worldwide. The water level in most groundwater-bearing rock layers, known as aquifers, has fallen drastically almost everywhere in the world since 1980. And since 2000, this decline in groundwater reserves has accelerated. The effects are most pronounced in aquifers in the world’s arid regions, including California and the High Plains in the US, along with Spain, Iran, and Australia.
“We weren’t surprised that groundwater levels have fallen sharply worldwide, but we were shocked at how the pace has picked up in the past two decades,” Seybold says.
One of the reasons Seybold cites for the accelerated drop in groundwater levels in arid regions is that people use these areas intensively for agriculture and are pumping (too) much of the groundwater to the surface to irrigate crops, for example in California’s Central Valley.