The world is running out of water. Humans are polluting, depleting, and diverting its finite freshwater supplies so quickly, we are creating massive new deserts and generating global warming from below.

In many parts of the world, surface waters are too polluted for human use. Ninety per cent of wastewater in the Third World is discharged untreated. Eighty per cent of China's and 75 per cent of India's surface waters are too polluted for drinking, fishing, or even bathing. The story is the same in most of Africa and Latin America.

Humans, using powerful new technology, are mining groundwater sources far faster than they can be replaced, creating drought in once-fertile areas. When water is taken from an aquifer to grow crops in the desert, another desert is created. A recent scientific report from the United Kingdom warned of "coming anarchy" in Asia as water is sucked out of the ground by untold millions of bore wells.

Water is also massively displaced through the building of large dams, the main reason so many of the great rivers of the world no longer reach the oceans. Around the world, a massive network of pipelines is being constructed to move water from place to place, similar to the pipeline network that now moves oil and gas. Water is transferred -- sometimes great distances -- for flood irrigation that creates more deserts as it over-tills topsoil, leaving it to blow away in the wind. Water is removed from rivers, wetlands and aquifers and ends up as sewage.

Huge amounts of water are also displaced through the trade in "virtual water" where poor countries grow water-intensive crops for export to countries trying to conserve their water supplies. They are left with dead lakes and rivers.

Further, urban sprawl is creating huge "heat islands" unable to absorb rain. The destruction of water-retentive landscapes means that less precipitation remains in river basins and continental watersheds; this in turn, equates to less water in the hydrologic cycle.

In Canada, we have tended to ignore water problems, believing that we have plentiful supplies. But recent studies suggest otherwise, particularly in the western prairies, where water has been scarce at the best of times. The climate of the Prairie provinces has already warmed by from 1to 4C, and is predicted to warm that much again by mid-century. Already, snowpacks and glaciers of the Rocky Mountains, the "water towers" of the prairies, are dwindling, and increasing evaporation is stealing more water from lakes, rivers and soils as a result of warmer temperatures.

One concern is for agriculture, because soil moisture is predicted to decrease over vast semi-arid areas of the prairies where crops are already limited by water supplies in many years. This has resulted in a call by big agribusiness for more dams and reservoirs. Experience elsewhere shows that these are of questionable value if benefits and costs are weighed honestly.

In the words of Daniel P. Beard, recently retired Commissioner of th U.S. Bureau of Reclamation, reflecting on America's many dam projects of the 20th century: "we reaped great benefits, but there were very great costs. For some, the jury is still out whether the benefits outweigh the costs. But for many the answer is simple: we have paid too dearly for 'cheap' power and water."

Alberta, with its rapidly growing population and industry, is "ground zero" for water shortages in Canada. Already, the provincial government has declared a moratorium on new water licences for the Bow and Oldman rivers, which recent studies show are vastly overutilized by irrigated agriculture and growing municipalities. Controversy has arisen over new proposals to divert water from the Red Deer River to support development in watersheds that have already outstripped their water supplies.

Another concern is the vast water needs of the oilsands, which rely on water from the Athabasca, the only remaining free-flowing large river of the Prairie provinces. Approved developments are expected to take 11 per cent of winter low flows in the Athabasca in dry years. Climate warming and destruction of tributaries and wetlands in the Athabasca watershed undoubtedly make this a conservative estimate.

So far, water problems have been ignored by federal and provincial politicians, despite their recent posturing in the "greenest cloak" competition. Canadians should demand rapid action from their elected representatives to secure and protect our freshwater supplies, protecting them from the ravages of climate warming, frivolous use, pollution and export to other countries.

The security of our grandchildren's Canada depends on it.

David Schindler holds the Killam Memorial Chair and is Professor of Ecology at the University of Alberta. Maude Barlow is national chair of the Council of Canadians and author of an upcoming book, Blue Covenant:

The Global Water Crisis and the Fight for the Right to Water