Immense Reserves of Fresh Water May Exist Below the Ocean Floor

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    As much as 500,000 km³ of fresh water may exist in aquifers below the ocean floor on continental shelves around the world. A study produced by Australian scientists and published in the December 5th edition of the journal Nature reveals the existence of low-salinity water beneath South Africa, North America, Australia, and China.

    “The volume of this water resource is a hundred times greater than the amount we’ve extracted from the Earth’s sub-surface in the past century since 1900,” said Vincent Post, a groundwater hydro geologist from Flinders University in Adelaide and the new study’s lead author.

    UN Water, the United Nations’ water agency, estimates that water use has been growing at more than twice the rate of population in the last century due to demands such as irrigated agriculture and meat production. More than 40 percent of the world’s population already live in conditions of water scarcity. By 2030, UN Water estimates that 47 percent of people will exist under high water stress.

    This new freshwater resource could give regions suffering with limited access to freshwater more options for combating the impact of droughts and alleviating the impact of water scarcity on future generations.

    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.

    Post said the deposits were comparable with the bore basins currently relied upon by much of the world for drinking water and would cost much less than seawater to desalinate. “It means that more options can be considered to help reduce the impact of droughts and continental water shortages,” Post said.