A GROWING THIRST

Humans may drink groundwater dry around the world

Experts say sources of groundwater in world’s arid regions are at risk of depletion,

WASHINGTON // Nearly two billion people could face severe water shortages by 2050 as groundwater resources are depleted, according to a study released this week.

“While many aquifers remain productive, economically exploitable groundwater is already unattainable or will become so in the near future, especially in intensively irrigated areas in the drier regions of the world,” said Inge de Graaf, a hydrologist at the Colorado School of Mines in Golden, USA. Humans could drink the groundwater almost dry in parts of India, southern Europe and the United States in the coming decades, according to computer models of the world’s groundwater resources.

Aquifers in the Upper Ganges basin area of India, southern Spain and Italy could be depleted between 2040 and 2060, according to the study presented at the autumn meeting of the American Geophysical Union in San Francisco on Thursday.

In California, aquifers in central and southern parts of the state could be depleted by the 2030s. Aquifers that Texas, Oklahoma and New Mexico rely on could reach their limits between the 2050s and 2070s.

In the next 34 years, as many as 1.8 billion people worldwide could live in areas where groundwater levels are fully or nearly depleted because of excessive pumping of groundwater for drinking and agriculture, Ms de Graaf and her fellow researchers found.

Previous studies have relied on satellite data to estimate groundwater levels.

The current study, which included researchers at Utrecht University in the Netherlands, aimed to simulate regional activity by studying aquifer structure, water withdrawals, and interactions between groundwater and surrounding water.

Billions of litres of groundwater are used daily for agriculture and drinking water worldwide.

While the latest study offers a new approach to estimating the limits of global groundwater, scientists are uncertain as to how much groundwater remains in each aquifer.