Map showing depletion of groundwater in northern India. The water table in northern regions, in red, is dropping rapidly due to irrigation, according to new research.. Groundwater supplies are increasing in the blue areas due to above-average rainfall. Image: Velicogna/UC Irvine
New research published in the journals Nature and Geophysical Research Letters based on satellite studies indicate that groundwater in northern India is being severely depleted by heavy pumping for agriculture. Like loss of fish in the sea from overfishing, groundwater loss also is a hidden crisis, a tragedy of the commons.
Groundwater serves as a primary source of freshwater in many parts of the world, and some regions are becoming heavily dependent on it. As a result, groundwater supplies are being depleted as we pump water out faster than aquifers replenish. This begins to create social unrest.
As a portion of overall global water supply, freshwater is extremely limited. Only about two and a half percent of all water is fresh, and most of that is locked up in ice. People in some regions also depend on mountain glaciers for their water supply, but these are disappearing because of rising temperatures.
About one third of our freshwater supply is found in underground aquifers, most of them ancient, or non-rechargable. Only a tiny fraction is renewed by snow and rain to recharge lakes and rivers, and we supplement these surface supplies with groundwater from aquifers.
Wow, powerful stuff when added to concerns over changing flow patterns from glacial and season snow melt! Very useful for those of looking at the region from a natural resources and geopolitics standpoint.
Posted by: Geoff Dabelko | August 15, 2009 at 01:23 PM