Skybird
04-17-08, 06:46 PM
http://www.spiegel.de/international/world/0,1518,druck-547976,00.html
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It's always been a disturbing what-if scenario for climate researchers: Gas hydrates stored in the Arctic ocean floor -- hard clumps of ice and methane, conserved by freezing temperatures and high pressure -- could grow unstable and release massive amounts of methane into the atmosphere. Since methane is a potent greenhouse gas, more worrisome than carbon dioxide, the result would be a drastic acceleration of global warming. Until now this idea was mostly academic; scientists had warned that such a thing could happen. Now it seems more likely that it will.
Russian polar scientists have strong evidence that the first stages of melting are underway. They've studied largest shelf sea in the world, off the coast of Siberia, where the Asian continental shelf stretches across an underwater area six times the size of Germany, before falling off gently into the Arctic Ocean. The scientists are presenting their data from this remote, thinly-investigated region at the annual conference of the European Geosciences Union this week in Vienna.
In the permafrost bottom of the 200-meter-deep sea, enormous stores of gas hydrates lie dormant in mighty frozen layers of sediment. The carbon content of the ice-and-methane mixture here is estimated at 540 billion tons. "This submarine hydrate was considered stable until now," says the Russian biogeochemist Natalia Shakhova, currently a guest scientist at the University of Alaska in Fairbanks who is also a member of the Pacific Institute of Geography at the Russian Academy of Sciences in Vladivostok.
The permafrost has grown porous, says Shakhova, and already the shelf sea has become "a source of methane passing into the atmosphere." The Russian scientists have estimated what might happen when this Siberian permafrost-seal thaws completely and all the stored gas escapes. They believe the methane content of the planet's atmosphere would increase twelvefold. "The result would be catastrophic global warming," say the scientists. The greenhouse-gas potential of methane is 20 times that of carbon dioxide, as measured by the effects of a single molecule.
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The future does not stop to be... interesting...
A greenhouse gas 20 times as potent as CO2, fine, but it becomes even better. What the article is not talking about is the geological stability provided by loose rocks and methanehydrate being frozen together. If this type of ice is melting , you have no longer a solid geological layer at the steep cliffs of the north-atlantic shelfs offcoast the Scandinavian region, but a slide where in a chain reaction biblical ammounts of scree could fall off the shelf's slopes and up to three kilometers down to the bottom of the Atlantic ocean. This effect could produce a cascade that - in worst case scenario - could race along the complete shelf at the length of the Scandinavian coast.
And a maritime earthslide of this dimension would mean an Atlantic Tsunami man cannot remember from history.
It probably depends on the speed of the methanehydrate becoming instable.
(...)
It's always been a disturbing what-if scenario for climate researchers: Gas hydrates stored in the Arctic ocean floor -- hard clumps of ice and methane, conserved by freezing temperatures and high pressure -- could grow unstable and release massive amounts of methane into the atmosphere. Since methane is a potent greenhouse gas, more worrisome than carbon dioxide, the result would be a drastic acceleration of global warming. Until now this idea was mostly academic; scientists had warned that such a thing could happen. Now it seems more likely that it will.
Russian polar scientists have strong evidence that the first stages of melting are underway. They've studied largest shelf sea in the world, off the coast of Siberia, where the Asian continental shelf stretches across an underwater area six times the size of Germany, before falling off gently into the Arctic Ocean. The scientists are presenting their data from this remote, thinly-investigated region at the annual conference of the European Geosciences Union this week in Vienna.
In the permafrost bottom of the 200-meter-deep sea, enormous stores of gas hydrates lie dormant in mighty frozen layers of sediment. The carbon content of the ice-and-methane mixture here is estimated at 540 billion tons. "This submarine hydrate was considered stable until now," says the Russian biogeochemist Natalia Shakhova, currently a guest scientist at the University of Alaska in Fairbanks who is also a member of the Pacific Institute of Geography at the Russian Academy of Sciences in Vladivostok.
The permafrost has grown porous, says Shakhova, and already the shelf sea has become "a source of methane passing into the atmosphere." The Russian scientists have estimated what might happen when this Siberian permafrost-seal thaws completely and all the stored gas escapes. They believe the methane content of the planet's atmosphere would increase twelvefold. "The result would be catastrophic global warming," say the scientists. The greenhouse-gas potential of methane is 20 times that of carbon dioxide, as measured by the effects of a single molecule.
(...)
The future does not stop to be... interesting...
A greenhouse gas 20 times as potent as CO2, fine, but it becomes even better. What the article is not talking about is the geological stability provided by loose rocks and methanehydrate being frozen together. If this type of ice is melting , you have no longer a solid geological layer at the steep cliffs of the north-atlantic shelfs offcoast the Scandinavian region, but a slide where in a chain reaction biblical ammounts of scree could fall off the shelf's slopes and up to three kilometers down to the bottom of the Atlantic ocean. This effect could produce a cascade that - in worst case scenario - could race along the complete shelf at the length of the Scandinavian coast.
And a maritime earthslide of this dimension would mean an Atlantic Tsunami man cannot remember from history.
It probably depends on the speed of the methanehydrate becoming instable.