The report by the Sage Centre and the World Wildlife Fund (WWF) examined the impact of a small rise in temperatures on the Athabasca River, which feeds Canada's Alberta oil sands industry, and on its Great Lakes region, where vast hydro-electric power is generated for Ontario province and exported to the northeastern United States.

Global temperatures have already risen by about 0.8 degrees Celsius (1.4 degrees Fahrenheit) in the past century and are expected to rise by 2.0 degrees Celsius (3.6 degrees Fahrenheit) between 2026 and 2060.

Different regions in Canada could warm by up to 6.0 degrees Celsius (11.8 degrees Fahrenheit).

This could lead to changes in rainfall patterns, more evaporation from lakes and rivers, and less glacial flow resulting in lower river flows and lake levels, the WWF said in a statement.

Ontario would be forced to cut hydro power generation by 2.0 to 17 percent and Alberta would have to curtail new oil sands projects, which now use 2.0 to 4.5 barrels of water and large amounts of energy to produce one barrel of oil.

"Canada's fastest growing source of global warming pollution -- the Alberta tar sands -- is boiling off the very water supplies it needs, and in Ontario, burning coal for electricity is undermining access to clean hydro power," Julia Langer, director of WWF's global threats program, said in a statement.

"Only decisive action to dramatically cut fossil fuel pollution can stop this tragic irony," she said.

The WWF called for cuts to carbon gases emitted mainly by burning oil, gas and coal that are driving perilous climate change, particularly from Alberta oil sands production, and no new water-taking permits for energy companies.

Canada had agreed under the Kyoto Protocol to reduce carbon dioxide emissions to 6.0 percent below 1990 levels by 2012, but a recent government environmental audit found emissions had instead increased by 26.6 percent.

Carbon emissions from increased oil sands extraction operations, already Canada's worst polluter, could double by 2015, the government's environmental auditor Johanne Gelinas said.

Environment Minister Rona Ambrose introduced a bill in mid-October to reduce Canada's carbon emissions by 45-65 percent by 2050, based on 2003 emissions. But, it was widely panned for allowing emissions to continue to rise until 2020.

At an estimated 179 billion barrels, Canada's oil sands rank second behind Saudi Arabia's in petroleum reserves. However, due to high extraction costs, the deposits were long neglected, except by local companies.

While crude is pumped from the ground, oil sands must be mined and bitumen separated from the sand and water.

Since 2000, skyrocketing crude prices and improved extraction technology have persuaded foreign companies to invest billions of dollars in projects.

Oil sands output is expected to triple over the next decade to 3.5 million barrels of oil per day, the Organization for Economic Cooperation and Development said in its annual report in June.

However, the WWF said water flows in the Athabasca River, down 20 percent since 1958, could diminish by another seven to 10 percent if local temperatures continue to rise.

"Flows will be insufficient to satisfy the needs of oil sands production, as well as other industrial, commercial, agricultural, municipal and environmental users," the report states.

Water levels in the Great Lakes, meanwhile, could fall by up to 1.2 meters (four feet) due to evaporation as temperatures increase, it says.

Recent drops of up to 0.5 meters (1.6 feet) below average on Lakes Huron, Michigan and Superior have caused problems for navigation, recreation, power generation and the local ecology, the study notes.

Reduced river and lake water volume combined with increased water temperatures would also threaten water quality as pollutants become more concentrated, it says.

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