After analyzing 14 years worth of climate data, scientists at the National Aeronautics and Space Administration (NASA) have mapped the impact that humans have made on the world’s freshwater supplies. The data was collected as part of a mission by NASA’s Gravity Recovery and Climate Experiment (GRACE) satellites. The new information not only tells us how humans are impacting water supplies but gives us clues as to how we can prevent any negative effects from continuing.

The GRACE satellites monitored both increases and decreases in the freshwater supply. They measured the strength of Earth’s gravitational pull in certain areas and compared them to the mass of the Earth in those areas over time. These calculations helped to determine how much of that mass was water and whether the amount of water was increasing or decreasing. This technique is very helpful for studying freshwater. Freshwater is often hidden underground, trapped in glaciers, or flowing through rivers. Its supply also changes very frequently due to storms, droughts, and the natural cycle of seasons. These factors make freshwater difficult to measure, but the GRACE satellites’ cutting-edge technology is able to complete the job.

NASA’s study identified 34 “hotspots” where the most significant impact occurs. They are scattered across the globe, with multiple water increase and decrease hotspots on each continent. There are two prominent water loss hotspots in the US: one in Texas and one in California. California’s water decrease is caused mainly by excessive pumping of groundwater. Due to the ongoing drought, the state’s thousands of farms depend heavily on groundwater to keep their crops alive. Southern California alone lost 4 gigatons of water each year from 2002 to 2016. That’s about 1056 billion gallons, which is enough to fill more than a million Olympic swimming pools.

The depletion of available freshwater in California, as well as in other food-producing regions like southwest America, northern China, the Middle East, and India, is alarming. The reason behind the water shortages in these areas is the unchecked pumping of groundwater for irrigation. According to water scientist Jay Famiglietti, “groundwater continues to be undermanaged, if managed at all. And that’s why we see the rapid disappearance.” Aquifers are being emptied out faster than they are being replenished. For some areas, it is only a matter of years before the water runs out.

Researchers warn that at this point in the global water crisis, careful planning and rules limiting water usage may be the only way to save the natural resource. All people depend on water for food, drink, sanitation, and countless other things often taken for granted. Hopefully, this study helps governments realize the urgent need to regulate the amount of water being pumped from the Earth and inspires people to do their part in reducing human impact on the world’s water.