Courtesy of NASA Earth ObservatoryThe Aral Sea in 2015. The body of water has shrunken in size dramatically in recent years due to water withdrawals from rivers that feed it.
A 14-year NASA mission has confirmed that a massive redistribution of freshwater is occurring across the Earth, with middle-latitude belts drying and the tropics and higher latitudes gaining water supplies.
The results, which are probably a combination of the effects of climate change, vast human withdrawals of groundwater and simple natural changes, could have profound consequences if they continue, pointing to a situation in which some highly populous regions could struggle to find enough water in the future.
“To me, the fact that we can see this very strong fingerprint of human activities on the global water redistribution, should be a cause for alarm,” said Jay Famiglietti, a researcher at NASA’s Jet Propulsion Laboratory and one of the authors of a new study published in Nature on Wednesday.
The results emerge from the 2002-2016 GRACE mission, which is short for Gravity Recovery and Climate Experiment, supplemented with other additional data sources. The GRACE mission, which recently ended but will soon be replaced by a “Follow-On” endeavor, consisted of two twin satellites in orbit that detected the tug of the Earth’s gravity below them – and monitored mass changes based on slight differences in measurements by the two satellites.
Among all the very massive features on the Earth, water and ice are the ones that change most regularly. Thus, the GRACE data have been used to detect anything from the vast losses of ice in Greenland, Antarctica and Alaska, to changes in ocean currents, to the scale of the California drought.
The new research, led by NASA’s Matthew Rodell, pulls together these and other findings to identify 34 global regions that either gained or lost more than …read more
Source:: The Denver Post – World