A new analysis reveals that global water scarcity is a far greater problem than previously thought, affecting 4 billion people—two-thirds of the world’s population—and will be “one of the most difficult and important challenges of this century.”
Previous analyses looked at water scarcity at an annual scale and had found that water scarcity affected between 1.7 and 3.1 billion people. The new study, published in the journal Science Advances, assessed water scarcity on a monthly basis, more fully capturing the specific times of year when it could be an issue.
“Water scarcity has become a global problem affecting us all,” study co-author Arjen Hoekstra, a professor of water management at the University of Twente in the Netherlands, said.
The study found that almost half of the 4 billion affected by severe water scarcity for a month or more are in India and China. Millions of others affected live in Bangladesh, Nigeria, Pakistan and Mexico.
The U.S. is far from immune to the problem, with 130 million people affected by water scarcity for at least one month a year, mostly in the states of Texas, California and Florida. And among the rivers the study notes that are fully or nearly depleted before reaching their end is the Colorado River in the West.
There are also half a billion people who face severe water scarcity year round, the analysis found.
The study concludes that “meeting humanity’s increasing demand for freshwater and protecting ecosystems at the same time … will be one of the most difficult and important challenges of this century.”