Global warming and climate change are likely to unfold a water crisis in the United States within the next 40 years, says a new report.

It concluded that seven in 10 of the more than 3,100 US counties could face risk of fresh water shortages. The report includes maps that identify those places.

Sujoy B. Roy, director for research and development (R and D), Tetra Tech Inc., Lafayette, US, and colleagues explain that population growth is expected to increase the demand for water for municipal use and for power generation beyond existing levels.

Global climate change threatens to reduce water supplies due to decreased rainfall and other factors compared to levels in the 20th century, the Journal of Environmental Science and Technology reports.

Roy's group developed a "water supply sustainability risk index" that takes into account water withdrawal, projected growth, susceptibility to drought, projected climate change and other factors in individual US counties for the year 2050, according to an American Chemical Society statement.

Roy's team used the index to conclude that climate change could foster an "extreme" risk of water shortages that may develop in 412 counties in southern and southwestern states and in the southern Great Plains.

"This is not intended as a prediction that water shortages will occur, but rather where they are more likely to occur, and where there might be greater pressure on public officials and water users to better characterize, and creatively manage demand and supply," Roy said.

Source: Indo-Asia News Service