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Science Frontiers ONLINE No. 129: MAY-JUN 2000 |
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Leaky Seas
Within a billion years, our planet could be as dry and barren as Mars, claim geologists in Tokyo. They have calculated that the oceans are leaking water into the Earth's mantle five times as fast as it is being replenished.
It is true that ocean water is being drained away at subduction zones where oceanic crustal plates dive under the continental plates; there's a 10,000-mile unsealed crack there. S. Maruyama and colleagues at the Tokyo Institute of Technology estimate that 1.12 billion metric tons of water leak through that crack in the earth's integument every year. Geologists have always assumed that most of this leakage was returned to the oceans through deep-sea vents and volcanic action, but Maruyama calculates that only 0.23 billion metric tons are recovered. The balance is probably absorbed by lawsonite and other minerals forming 100 kilometers below the surface.
(Hadfield, Peter; "Leaky Seas," New Scientist, p. 4, September 11, 1999.)
Comment. Does this mean we should cease our attempts to stem global warming?
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