- Humans have profoundly changed the global water landscape, the study finds.
- As a result, some spots become wet and other areas dry out.
The position of fresh water around the world is constantly changing and humans are the driving force behind the movements, according to a new study by NASA scientists.
As a result, some places become wetter and other areas dry out.
"The human fingerprint is everywhere over changing fresh water availability, we see it in large-scale overuse of groundwater and we see it as a driver of climate change," said Jay Famiglietti, a co-author of research, the Senior Water Scientist at Jet NASA's Propulsion Laboratory in Pasadena, California. "The study shows that humans have drastically changed the global aquatic landscape."
Using NASA satellites and data on human activities to map freshwater sites around the world, researchers found several factors involved in shifts, including water management practices, climate change and natural cycles. The study was published on Wednesday in the journal Nature.
Researchers led by Matt Rodell of NASA's Goddard Space Flight Center in Greenbelt, Maryland, observed global trends in freshwater in 34 regions or hotspots around the world based on 1
At least 40 percent of the world's 34 hotspots can be linked to human water management activities such as: For example, excessive groundwater pumping for agriculture. These include areas such as North India, the North China Plain and parts of Saudi Arabia.
Meanwhile, the changes in eight regions can be linked to climate change, while the shifts in the remaining 12 regions can be linked to natural factors such as cyclic weather patterns, according to the study
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Co-author Jay Famiglietti of NASA's Jet Propulsion Laboratory said that although water loss in some regions is clearly dictated by a warming climate, "this will require more time and data to complete driving forces behind other patterns of freshwater change. "
" The wet-wet, drying-dryer pattern during the remainder of the 21st century will change models predicted by the Intergovernmental Panel on Climate, but we need a much longer dataset, to be able to say definitively whether climate change is creating a similar pattern in the United States GRACE data, "he said.
The depletion of fresh groundwater in some regions is not limited to excessive pumping but can also be compounded by cycles of persistent drought or rainy conditions, researchers said.
The reduction in groundwater from 4 gigatonnes of water per year between 2002 and 2016 in Central Valley, California, is an example of reduced groundwater replenishment due to rainfall and snowfall combined with increased pumping volumes for agriculture, the study said. For comparison, one gigat of water would fill 400,000 Olympic swimming pools.