Washington: Although some 72 per cent of Earth's surface is covered with water, the planet might be doomed to face a major water crisis in the future.

Climate change has altered the water cycle so much that a looming water shortage awaits the Earth, scientists said.

Water availability will decrease substantially in the West Asia, southern Europe, southern Africa and southwestern North America, hydrologist with the US Geological Survey said and estimated more frequent droughts in drying areas.

The changes in the climatic condition magnifies the possibility that the future will bring droughts or floods to the measure that has never been witnessed in the past, the researchers told Science magazine.

Climate change has already altered rainfall patterns and river flows and created a greater risk of flooding in some areas. The researchers linked sharp changes in water supplies in the western United States to global warming.

They studied why more winter precipitation was falling as rain instead of snow and why snow was melting earlier in the western US, an arid region with a growing population.

The researchers concluded that up to 60 per cent of the climate-related trends of river flow, winter air temperature and snow pack were due to human-caused climate change from greenhouse gases and aerosols.

Source : UNI