Severe water shortages will affect more than half the world’s future population of nine billion people by 2050 if governments fail to collaborate on international efforts to protect and conserve life’s most vital ingredient, experts have warned. One of the first indications of a future water crisis will be mass migrations of people away from areas without water.

Political tensions are likely to follow the movements of environmental refugees, Professor Janos Bogardi, of Bonn University, a senior adviser to the water system project, said. Five hundred of the world’s leading water scientists said that the current mismanagement and misuse of increasingly scarce water resources threatens to plunge most of the global population into extreme water poverty.

They said that human activity has accelerated major disturbances to supplies of fresh water, such as erosion, pollution and the draining of rivers and underground aquifers. An extra two billion people in the world by 2050 will exacerbate the global crisis, they said.

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“In the short span of one or two generations, the majority of the nine billion people on Earth will be living under the handicap of severe pressure on fresh water, an absolutely essential natural resource for which there is no substitute,” the scientists said.

“This handicap will be self-inflicted and is, we believe, entirely avoidable…. Mismanagement, overuse and climate change pose long-term threats to human well-being, and evaluating and responding to those threats constitutes a major challenge to water researchers and managers alike,” they said in a joint declaration.

“Humans are a key feature of the global water system, influencing prodigious quantities of water: stored in reservoirs, taken from rivers and groundwater and lost in various ways. Additional deterioration through pollution, now detectable on a global scale, further limits an already-stressed resource base, and negatively affects the health of aquatic life-forms and human beings.”

The meeting in Bonn organised by the Global Water System Project found that water is becoming one of the most serious factors that could limit human development in the 21st century, with an increasing number of people affected by a water shortage so severe that it is affecting their well-being.

The scientists working on the water project concluded that the increase in the use of water around the world, combined with the permanent degradation of existing water supplies, is currently on an “unsustainable trajectory” that could lead a global tipping point in the near future.

“However, current scientific knowledge cannot predict exactly how or precisely when a planetary-scale boundary will be breached. Such a tipping point could trigger irreversible change with potentially catastrophic consequences,” they warned.

Professor Bogardi said that very profound changes to the way people treat water supplies are needed if humanity is to avert the environmental disaster of wide-scale water shortages. “I’m optimistic that we can pull ourselves out of this mess but I don’t know how we are going to do it yet,” he said.