The heavily-populated regions of Asia, the arid Middle East and parts of the Unites States corn belt are dangerously over-exploiting their underground water supplies, according to a study published on Wednesday in the Nature journal. “The countries that are overusing groundwater most significantly are Pakistan, US, India, China, Iran, Saudi Arabia and Mexico, and the highest number of people that are impacted by this live in India and China,” Canadian hydrologist Tom Gleeson told AFP. “Over a quarter of the world’s population live in these regions where groundwater is being overused,” he said in a phone interview.
Many places are rapidly pumping out “fossil” water, or water that was laid down sometimes thousands of years ago and cannot be replaced on a human timescale. Seeking a yardstick of sustainability, the study creates a measure called the groundwater footprint. It calculates the area of land sustained by extracted water and compares this to the size of the aquifer beneath. The global groundwater footprint is a whopping 3.5 times the size of the world’s aquifers, the study found. However, this stress is accounted for by a small number of countries. For instance, in the South Caspian region of northern Iran, the footprint is 98 times the size of the aquifer; in the Upper Ganges in India and Pakistan, it is 54; while in the US high plains, the figure is nine.
In March, the UN warned in its fourth World Water Report that water problems in many parts of the world were chronic, and without a crackdown on wastage, the situation would worsen as demand for food rises and climate change intensifies.
Published in The Express Tribune, August 10th, 2012.