11 percent of disappearing groundwater used to grow internationally traded food.
To produce these crops many countries rely on irrigated agriculture that accounts for about 70 percent of global freshwater withdrawals, according to the United Nations Water program.
A new study by researchers at the University College London and NASA’s Goddard Institute of Space Studies in New York City shows that 11 percent of the global non-renewable groundwater drawn up for irrigation goes to produce crops that are then traded on the international market.
Additionally, two-thirds of the exported crops that depend on non-renewable groundwater are produced in Pakistan (29 percent), the United States (27 percent), and India (12 percent).
Their analysis is the first to determine which specific crops come from groundwater reservoirs that won’t renew on human time-scales and where they are consumed.
"It’s important from Japan’s perspective to know whether that corn is being produced with a sustainable source of water, because you can imagine in the long term if groundwater declines too much, the United States will have difficulty producing that crop."
Countries that export and import these crops may be at risk in the future of losing the crops, and their profits, produced with non-renewable groundwater.
Aquifers form when water accumulates in the ground over time, sometimes over hundreds or thousands of years.
Non-renewable aquifers are those that do not accumulate rainfall fast enough to replace what is drawn out to the surface, either naturally to lakes and rivers or in this case by people via pumping.
"What’s innovative about this study is it connects groundwater depletion estimates with country level data," said hydrologist Matt Rodell at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who was not involved in the study.