The ongoing drought in the western United States has caused so much loss of groundwater that the Earth, on average, has lifted up about 0.16 inches over the last 18 months, according to a new study.
The situation was even worse in the snow-starved mountains of California, where the Earth rose up to 0.6 inches.
“It’s predominantly in the Coast Ranges and the Sierras showing the most uplift, and hence, that’s where we believe is the largest water loss.” That’s also about how much ice is lost from the Greenland ice cap every year from global warming.
But the GPS data can also be used to show very small changes in elevation. Groundwater is very heavy, and its weight depresses the Earth's upper crust. Remove the weight, and the crust springs upward — and GPS sensors can detect how much higher the land has risen as a result of loss of groundwater.
“You can only lose water where there’s water to lose,” Agnew said.