NASA scientists have used data obtained from Earth-observing satellites to track changes in water supplies worldwide. The research team relied heavily on 14 years of images from NASA’s Gravity Recovery and Climate Experiment (GRACE) mission. The twin GRACE satellites were launched back in 2002 as a joint mission with the German Aerospace Center (DLR).
The researchers also incorporated climate data from the Global Precipitation Climatology Project into the research.
According to the study, human activities are dramatically altering the global water map. While wetland areas are getting wetter, dry areas are getting drier from groundwater depletion, thus representing a major shift in water distribution. The scientists have attributed the change in global trends in freshwater to a variety of factors, including human water management, climate change, and natural cycles.
“We know for sure that some of these impacts are caused by climate change,” said Matt Rodell, lead author of the study from NASA’s Goddard Space Flight Center.
Rodell said that this is the first time that they have used observations from multiple satellites in a thorough assessment of how freshwater availability is changing on Earth.
Using the study results, the research team located 19 hotspots from 34 regions in the world currently witnessing the most dramatic water changes. Notably, 14 of the hotspots can be attributed directly to human activity including Australia, the Middle East, Northern India, Northern Africa, Southern California, and Southern Russia.
“What we are witnessing is major hydrologic change,” said co-author Jay Famiglietti of NASA’s Jet Propulsion Laboratory in Pasadena, California.
Famiglietti added that the research team found a distinctive pattern of the wetland areas of the world getting wetter and the dry areas in between getting dryer. He said that multiple hotspots have been found within the dry areas due to groundwater depletion.
The study results have been published in the journal Nature.