population swells. Some say World War III will be fought over access to it. But newfound reserves of freshwater under the sea may represent a vast source that has been previously overlooked.

Researchers announced this week that they?ve probed the extent of freshwater reserves under the sea off the coasts of South Africa, China, North America and Australia. Scientists have known about these pockets for a while but had no idea how many or how large they were. Now researchers estimate they contain about 120,000 cubic miles of water. Each cubic mile is equivalent to 1.1 trillion gallons, enough water to satisfy all of the United States? present water usage for about 9 days. 

The deposits were formed over hundreds of thousands of years in the past, when the sea level was much lower and areas now under the ocean were exposed to rainfall which was absorbed into the underlying water table. When the polar icecaps started melting about 20,000 years ago these coastlines disappeared under water, but their aquifers remain intact — protected by layers of clay and sediment.

Since it isn?t as salty as seawater, the reserves would be easier and cheaper to desalinate for consumption. The researchers say these freshwater reserves could sustain certain regions of the world for decades.