Changes in climate can rapidly impact even the deepest freshwater aquifers according to Penn State and Columbia University hydrologists.
"These aquifers are so deep, we expect it takes years for precipitation to make its way down, so if it’s not natural recharge causing the response of groundwater to changes in precipitation, then it may be coming from pumping changes."
The research, published in Nature Geoscience, sheds new light on groundwater budgets in the U.S. and better defines how water held in deep aquifers could change with the climate.
Groundwater used by municipalities and industry is almost always drawn from deep wells, which provide a more reliable source of water than shallow aquifers, especially during times of drought.
Despite the importance of these deep aquifers, no one really knows how much water they contain or how they might react to climate change.
"But we actually see a relatively rapid response."
Russo said evidence suggests that pumping represents an intermediate connection between precipitation and deep groundwater levels.
"If you look at agricultural areas where you have crop water demand changing as a function of precipitation, that is going to control pumping variability over time," Russo said.
"Pumping could be an intermediate connection between climate and groundwater — one that causes an immediate response."
Though evidence suggests pumping causes the rapid response between deep groundwater and climate, scientists were not able to conclusively link them because of a lack of pumping data across the U.S. "We need more data collection on human activities," Russo said.