The Total Amount Of Freshwater On Earth Has Dropped Significantly Since May 2014, And It’s Only Getting Lower
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.
schankz – stock.adobe.com – illustrative purposes only
The reduction in global freshwater started with a widespread drought in northern and central Brazil.
Shortly after, a series of major droughts occurred in Australia, New Zealand, North America, South America, Europe, and Africa.
In the tropical Pacific, warmer ocean temperatures from 2014 to 2016 led to one of the most notable El Niño events since 1950, shifting weather and rainfall patterns worldwide.
But even after El Niño eased up, global freshwater levels failed to bounce back. The team reported that 13 of the 30 most intense droughts in the world took place since 2015. They suspect that global warming is playing a part in the dwindling freshwater levels.
Global warming causes the atmosphere to retain more water vapor, resulting in extreme precipitation.
The total yearly rain and snowfall levels might not change all that much, but long, dry periods between precipitation events make the soil dry out and become more compact.
Then, when it does rain, the ground is unable to absorb as much water. Instead of soaking in and replenishing the groundwater, it runs off.
So far, it is unclear if global freshwater will return to normal levels as they were before 2015, remain the same, or continue declining.
The study was published in Surveys in Geophysics.
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