Friday, September 25, 2015

GRACE satellites: humankind is running out of water

Twin GRACE satellites, launched by NASA in 2002, provided data for a study of the world's 37 largest aquifers, which  found that more than a third of them are being used at unsustainable rates — they are being drained far faster than natural processes can restore them. 13 of the 37 aquifers, from California to the Middle East to China, are running out of water.
 Eight of the 13 were determined to be overstressed, with no replenishment at all. Five were declared extremely stressed or highly stressed, with some replenishment but not enough to sustain their use. The Arabian Aquifer System supplies water to 60 million people in the Middle East and was declared in the study to be the most overstressed water supply in the world. The Indus Basin aquifer in India and Pakistan is the second most overstressed system. The satellites showed that the California  needs 11 trillion gallons of water to fall as rain or snow to recover, which is 50% more than the largest aquifer in the United States can hold.  Read more at