A sweeping new study has uncovered alarming evidence of unprecedented freshwater loss across Earth’s continents since 2002, warning of dire consequences for water security, food production, and sea-level rise. Led by Arizona State University and published in Science Advances, the study analyzed over two decades of satellite data and found that global groundwater depletion is accelerating faster than previously understood pushing parts of the planet toward what researchers call a “freshwater bankruptcy.”
The findings identify four massive “mega-drying” zones, all in the Northern Hemisphere, where freshwater reserves have plunged due to climate change, prolonged droughts, and unsustainable groundwater use. These drying regions include the American Southwest and Central America, Alaska and Northern Canada, Northern Russia, and a sweeping zone that spans from the Middle East and North Africa through parts of Europe and Asia.
“This is perhaps the most alarming message yet about the impact of climate change on global water systems,” said Jay Famiglietti, principal investigator of the study and professor at ASU’s School of Sustainability. “Groundwater overuse is now contributing more to sea-level rise than the melting of Greenland and Antarctica combined.”
Researchers used data from NASA’s GRACE and GRACE-FO satellite missions, which track changes in Earth’s gravity to estimate shifts in water mass on land. Their analysis shows that 68% of the net freshwater loss over the past 22 years came from groundwater. More than three-quarters of the world’s population live in countries that have been losing freshwater during this period.
Even more troubling, the study found that dry areas are expanding at a rate twice the size of California each year, while once-predictable global water cycles have begun to reverse. “The rate at which dry areas are getting drier now outpaces the rate at which wet areas are getting wetter,” explained lead author Hrishikesh A. Chandanpurkar, a research scientist at ASU. “That’s a major shift in the planet’s hydrological balance.”
The researchers also identified a tipping point between 2014 and 2015, marked by a “mega El Niño” event that triggered more extreme climate behavior. Since then, the shift in water storage patterns has intensified. Snow and permafrost melting surged in high-latitude regions like Canada and Russia, while drought worsened in mid-latitude agricultural zones in Europe, North America, and Asia.
The implications are massive: as ancient water reserves in deep aquifers vanish and glaciers shrink, sea levels rise, farming becomes riskier, and billions face growing uncertainty about where their water will come from. “Instead of saving groundwater and glaciers for times of need, we’re draining them constantly with no replenishment in sight,” said Chandanpurkar.
The four identified mega-drying regions stretch across critical urban and agricultural zones, including Phoenix, Los Angeles, Mexico City, British Columbia, Siberia, Cairo, Dhaka, and Beijing. Together, these areas represent some of the world’s most populated and food-dependent regions, and their drying has wide-reaching global consequences.
The study also revealed an unexpected finding: only the tropical regions have consistently gotten wetter, defying projections from international climate models. This signals a need for more real-time monitoring and ground-based data to understand what’s really happening across the planet’s freshwater systems.
As the world’s population continues to rise, the researchers say the urgency of the crisis cannot be overstated. Famiglietti emphasized the need for coordinated international action: “This is an all-hands-on-deck moment. We need new groundwater management strategies on a global scale. This is one area of climate resilience where real progress is still possible but only if we act now.”
The research will inform an upcoming flagship World Bank report examining the human and economic impacts of groundwater loss and offering policy solutions for countries confronting this growing crisis. In the meantime, the study calls for immediate reforms in water management, increased investment in monitoring systems, and international cooperation to avert a future defined by water scarcity and instability.