Emily Chan
After studying observations from NASA satellites, scientists have found evidence that the total amount of freshwater on Earth has dropped significantly since May 2014—and it has only continued to lower. According to the research team, the pattern suggests that Earth is currently in a dry phase.
Satellite measurements from 2015 to 2023 showed that the average amount of freshwater on land, including lakes, rivers, and water in underground aquifers, was 290 cubic miles lower than the average levels from 2002 to 2014.
Matthew Rodell, one of the authors of the study and a hydrologist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, stated that the amount is “two and a half times the volume of Lake Erie lost.”
Modern farms and cities depend on groundwater during times of drought, which can trigger a cycle of declining underground water. As freshwater supplies are used up, there is not enough rain and snow to replenish them. Meanwhile, more groundwater continues to be pumped.
The depleting water levels negatively affect farmers and communities, possibly leading to famine, poverty, conflicts, and an increased risk of disease when people are forced to turn to contaminated water sources.
The team identified the sudden global decrease in freshwater levels using observations from the Gravity Recovery and Climate Experiment (GRACE) satellites.
They are operated by the German Aerospace Center, the German Research Center for Geosciences, and NASA.
The GRACE satellites measure monthly fluctuations in Earth’s gravity that reveal changes in the mass of water both above and below ground.
The original GRACE satellites flew from March 2002 to October 2017. Their successors were launched in May 2018.
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