Most of the world’s aquifers are sustainable, but there are about 20% that are overusing groundwater, according to new research published in Nature. These non-sustainable aquifers provide water to an estimate of 1.7 billion people, mainly in regions of North America and Asia that still rely heavily on agriculture.
The researchers, led by Tom Gleeson of McGill University in Montreal, tried to determine the groundwater footprint in a number of aquifers across the world. The groundwater footprint is ‘the area required to sustain groundwater use and groundwater-dependent ecosystem services’, as they write in the paper, and it has hardly been studied.
‘The relatively few aquifers that are being heavily exploited are unfortunately critical to agriculture in a number of different countries,’ Tom Gleeson told Reuters. ‘So even though the number is relatively small, these are critical resources that need better management.’
The critical areas include the Central Valley in California, the Nile delta region of Egypt, and the Upper Ganges in India and Pakistan.
Photo: Wikimedia Commons
Tom Gleeson, Yoshihide Wada, Marc F. P. Bierkens, & Ludovicus P. H. van Beek (2012). Water balance of global aquifers revealed by groundwater footprint Nature DOI: 10.1038/nature11295
Charles R. Fitts