The planet is entering an era of global “water failure,” the United Nations research agency says, warning in a new report that long-term human water use has outstripped renewable water sources worldwide and potentially passed a point of no return.
“Failure” means that the Earth’s water reservoirs, such as rivers, lakes and aquifers, are being depleted at a faster rate than they can be replenished. the report By researchers at the United Nations University Institute for Water, Environment and Health (UNU-INWEH).
“In many regions, human water systems are already in a state of post-crisis failure,” the report’s authors wrote.
That failure, they say, is the result of decades of over-expansion, where “societies have withdrawn more water than climate and hydrology can reliably provide,” while environmental factors such as pollution have reduced the amount of water that can be safely used by degrading the quality. The consequences are measurable, especially in the deep regions of the Middle East and North Africa, South Asia and the southwestern parts of America.
Anmar Khalil / AP 
There are dozens of major rivers that do not reach the sea for parts of the year, and many river basins and aquifers have been “overfilling” their watersheds for at least the past five decades, according to the report. Half of the world’s great lakes have lost water since the early 1990s, a pattern of decline that affects roughly 25% of the world’s population. Increasing demand for that water, as well as changing inflows and rising temperatures, are largely to blame, researchers say.
While river basins also experience changes in their regular flow, wetlands, which scientists describe as traditional “shock absorbers” for the water cycle, are also disappearing. More than 1 billion natural wetlands have been wiped out in the past 50 years—an area roughly the size of continental Europe—threatening communities that help protect them from floods and droughts.
“These are not just signs of stress or crisis episodes,” the report said. “These are symptoms of systems that have overspent the hydrological budget and eroded the natural capital that once enabled recovery, with detrimental effects on food prices, employment, migration and geopolitical stability.”
About 75 percent of the human population lives in countries classified as “water insecure” or “critically water insecure,” the report said. This means their nations cannot reliably supply them with enough water that meets basic safety and quality standards.
Within this group, about 4 billion people experience severe water shortages for at least one month each year, 3.5 billion do not have access to safely managed sanitation and 2.2 billion do not have access to safely managed drinking water, the report says. Another 3 billion live in areas where total water storage is declining or unstable, and at least half of the world’s food is produced in these regions.
“Millions of farmers are trying to grow more food from shrinking, polluted or disappearing water sources,” said UNU-INWEH director and lead author Kaveh Madani. statement. “Without a rapid transition to water-smart agriculture, water failure will spread rapidly.”
The report recommends unifying efforts to address water failure, including restoring what is lost, addressing ongoing depletion, and adapting to available water.
“Water scarcity is becoming a driver of fragility, displacement and conflict,” UN Secretary-General Tshilidzi Marwala said in a statement. “Equity management – ensuring that vulnerable communities are protected and that inevitable losses are shared fairly – is today essential to maintaining peace, stability and social cohesion.”