Population growth, climate change and demand for greater food and energy supplies are squeezing global water supplies, according to a new U.N. report.
Water problems are often worst in developing countries, where water availability and prosperity are closely linked, says the report produced by 24 U.N. agencies and scheduled for official release tomorrow.
The report warns that mismanagement of water supplies has created problems that are "enormous ... but not insurmountable" -- if major policy shifts are made.
"Water is linked to the crises of climate change, energy and food supplies and prices, and troubled financial markets," the report says. "Unless their links with water are addressed and water crises around the world are resolved, these other crises may intensify and local water crises may worsen, converging into a global water crisis and leading to political insecurity and conflict at various levels."
A major factor affecting water availability is a surging global population, which the United Nations says could swell from 6.7 billion in 2008 to 9 billion by 2050.
And more and more of those people are living in urban areas, with much of that shift occuring in the poorest countries. That forces governments to rely on rivers and aquifers polluted by growing human settlements.
"Coping with a future without reliable water resource systems is now a real prospect in parts of the world," the report warns.
Another looming crisis: climate change.
Rising temperatures are shrinking snowpacks and glaciers, creating a potential crisis for more than 15 percent of the world's population that depends on snow and ice melt for its main water supply.
Climate change also has the potential to change patterns of drought and flooding. The report says, "In many places, climate-related water events have become more frequent and extreme."
And warmer water temperatures are likely to increase the frequency of algal blooms and the prevalence of toxic cyanobacteria and to reduce the diversity of species, the report adds.
The report, "Water in a Changing World," is the United Nations' third on freshwater. It is being released in advance of the World Water Forum, which begins Monday in Istanbul, Turkey.