WATER SECURITYPeak Water: Do We Have Enough Groundwater to Meet Future Need?
Though vast stores of groundwater persist below Earth’s surface, the climbing cost of accessing it is on track to significantly reshape the geography of trade and drive users toward alternative water sources.
A new study finds that, by mid-century, nearly half the global population could live in areas where groundwater will become so costly as to raise regional food prices and significantly alter the geography of trade and crop production. Nine percent of the world’s water basins appear to have already reached such a state of near depletion. The new research, led by scientists at the Department of Energy’s Pacific Northwest National Laboratory, suggests an additional 11.5 percent could reach this point by 2030, with another 22 percent joining by mid-century.
The authors of the new work sought to identify when and where water withdrawals from many of the world’s aquifers could “peak,” as in, when external forces could drive groundwater extraction to reach its maximum. Similar peaks have been observed in other resources, like fossil fuels or minerals.
But, until now, no study has observed and quantified the same behavior in groundwater. This new work marks the first time anyone has projected the peak and decline of water withdrawals in relation to demand from human-driven systems. It represents “the most extensive, large ensemble experiment focused on future global groundwater extraction to date,” said lead author and Earth scientist Hassan Niazi.
Though water is conserved within Earth’s hydrosphere and never truly “lost,” the new work affirms that groundwater does behave as a non-renewable resource, constrained in part by the cost of retrieval. Those who study groundwater recognize this, said coauthor and Earth scientist Tom Wild.
“While it’s not new for us to show that groundwater behaves like a nonrenewable resource,” said Wild, “our work provides a very stark and visible reminder of groundwater’s finite nature, given how similar our projected groundwater patterns are to other resources that are in the process of being exhausted.”
Yet the rate at which groundwater is extracted globally, said Niazi, runs counter to this idea. Withdrawal rates, after all, continue to rise.
“About a fifth of the world’s food is grown using groundwater,” said Niazi. “So, it’s important to recognize that groundwater, particularly that in deep aquifers, is finite, much like oil or copper. And understanding when this depletable resource will peak and decline can help us carve out an informed path forward, as many regions face the imminent challenge of reducing their groundwater reliance. That’s important because groundwater is tied to so many essential functions of society, from irrigation to energy and, inseparably, to the well-being of our environment.”
