Humans Are Driving Alarming Fluxes In Freshwater Sources, Says NASA

Cham women collecting water in the desert outside Phan Rang-Tháp Chàm, Vietnam

Aliyah Kovner 17 May 2018, 23:59

"This is the first time we've assessed how freshwater availability is changing, everywhere on Earth, using satellite observations," lead author Matt Rodell said in a statement. "A key goal was to distinguish shifts in terrestrial water storage caused by natural variability – wet periods and dry periods associated with El Niño and La Niña, for example – from trends related to climate change or human impacts, like pumping groundwater out of an aquifer faster than it is replenished.”

"What we are witnessing is major hydrologic change.”

In addition to confirming the previously identified patterns of intensified drought and flood, the results showed, unsurprisingly, that the largest freshwater fluxes happened in Antarctica, Greenland, the Gulf of Alaska coast, and Canadian archipelago; regions where global warming-driven ice melt has been most severe.  

Exemplifying the lunacy of farming in naturally arid areas, the team noted that southern California and Saudi Arabia lost about 4 and 6.1 gigatons of groundwater water per year, respectively, due to extraction for farm irrigation and several droughts. It is unlikely that the levels will ever fully bounce back.

Sizable water changes were also observed in northwestern China – a net depletion – and the Okavango Delta – where a theorized multi-decade-long dry-wet pattern appears to have switched toward wet.

"The pattern of wet-getting-wetter, dry-getting-drier is predicted by the Intergovernmental Panel on Climate Change models for the end of the 21st century, but we'll need a much longer dataset to be able to definitively say that climate change is responsible for the emergence of a similar pattern in the GRACE data," said co-author James Famiglietti. "However, the current trajectory is certainly cause for concern."

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