Free Press Journal

Could Earth become a water world?

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London:  Earth’s continental crust, which forms the land we live on, is getting thinner and could disappear entirely in two billion years, turning our planet into a waterworld, scientists have warned.   According to a new estimate, Earth’s continental crust has been slimming down and if this slimming rate holds, the continents might disappear into the sea.  As the continental crust erodes, land would disappear into the oceans, even without climate induced sea level rises, ‘New Scientist’ reported.  Bruno Dhuime of the University of Bristol, UK, and colleagues collated measurements of 13,000 rock samples fromaround the world to reconstruct the history of continental crust.

The team estimated the thickness of crust at different times in the past, inferring the rise and fall of continents over the Earth’s history.  Continents today are about 35 kilometres thick, on average, with the buoyant rock bobbing next to the 7-kilometre-thick, denser oceanic crust, which rides lower. Continental crust peaked in thickness about a billion years ago – around the time Earth’s mightiest continents banded together to form the supercontinent Rodinia. Researchers said the mountains raised by that event have been eroding ever since, and not enough new crust is formingto offset the losses. “If it continues for the next 2 billion years, then the crust will again reach that state where the continents are submerged beneath the ocean,” Dhuime added.