Humans are over-exploiting underground water reservoirs in many large agricultural areas in Asia and North America, sucking up water faster than nature can replenish it, according to a recent inventory of global aquifer use.
In a study published Wednesday in the journal Nature, scientists mapped the “groundwater footprint” of 15 major agricultural regions, including California’s Central Valley. The analysis, which gave spatial representation to rates of water extraction, concluded that the global groundwater footprint was 3.5 times greater than the size of all aquifers combined.
The heavy consumption of groundwater was driven by a handful of areas, according to lead author Tom Gleeson, a civil engineering professor at McGill University in Montreal.
The areas included the Upper Ganges in India and Pakistan, western Mexico, northern Saudi Arabia, Iran, the High Plains of the United States and the North China Plain. Although 80% of the world’s aquifers had a calculated footprint that was smaller than their actual size, these major agricultural regions contributed to a global deficit.