27 December 2007

Frozen Methane Clathrates Beneath the Seafloor: Waiting for Doomsday?

Deep in the Nankai trough off the southwestern coast of Japan, geologists from 21 countries are studying the makeup of rock beneath the seafloor. They are hoping to better understand the monstrous forces acting upon tectonic plates--that can cause killer earthquakes and tsunamis. But they are making other discoveries perhaps more important to man's fate on Earth.
The research team aboard the scientific drilling vessel Chikyu also found a methane hydrate-rich zone at one drill site, spreading out just 220 to 400 metres below the seafloor. This solid form of water, also known as methane ice, is believed to develop on the seafloor and deep in the sedimentary structures due to migration of gas from the depth of the Earth along geological faults that then crystallises on contact with cold sea water as a result of temperature and pressure. The ice contains large amounts of methane and is considered by some as a future source of fossil energy.

True, methane is a clean-burning fossil fuel that could potentially ease the transition from a fossil fuel economy to a cleaner, more sustainable energy economy. But is there a more sinister face to methane, hiding behind the beneficent appearance of an energy solution? China and India are pursuing the development of this undersea methane treasure trove, so it would be good to understand the potential dangers.
The People's Republic of China is investing millions to study this massive source of energy. The same holds true for India, South Korea and Taiwan, all nations that are on a fast track to surpassing the West as economic powers....World reserves of the frozen gas are enormous. Geologists estimate that significantly more hydrocarbons are bound in the form of methane hydrate than in all known reserves of coal, natural gas and oil combined....

If there is more methane beneath the seafloor than all other fossil fuels combined, the opportunity to use the cleaner fuel may be too great for China's monstrously consuming energy sector to ignore. India's huge population rivals that of China, which forces that country to pursue ever larger energy sources. What of the dangers?
Fifty-five million years ago the world's climate was catastrophically changed when volcanoes melted natural gas frozen in the seabed....

Some climate scientists claim that it was volcanic eruption causing massive methane release that killed the dinosaurs--not cometary or asteroid collisions. Their evidence is weak, but the more radical the claim--particularly if you can connect it with global warming--the better the research grant. If one could somehow break open the seafloor and decompress and unfreeze the frozen methane clathrates, it would be better not to light a match above the surfacing bubbles.

If geologists are to drill for methane beneath the seafloor, they had best do it carefully. Unlike CO2, methane actually is a strong greenhouse gas, and it is not a plant food. Like most of the industrial chemicals upon which modern civilisation is based, methane is useful as long as kept in its proper place.

In Cormac McCarthy's "The Road", he describes a world of ash and soot. A world without plant life, without ocean life. The soil itself is dead and cannot support life. It is a desolate world seemingly without hope.

Of course, McCarthy is an excellent writer but he is no scientist. The world he describes, populated by the people in the book, is not likely to exist. But if you can imagine a world where the very air is consumed in fire, where the earth burns, the ocean burns, where all plant and animal life dies except perhaps what is underground with a plentiful food, water, and air supply--you can imagine such a hopeless world.

Is there enough frozen methane buried underground and undersea to light up such a global conflagration? Perhaps. But if it is triggered, it will not be from anthropogenic global warming. Earth has seen much warmer days, the seas have been much warmer and more acidic, CO2 levels have been many multiples of current levels. Humans are not pushing the envelope of Earth's ability to adjust.

Only nature--in its volcanism, its seismic capacity, its ability to fling cosmic rock and ice onto the planet from space--only nature can trigger that doomsday. If it happens, many will claim that it was "God", and many will claim that it was man, who triggered the death. But it will be neither. Nature does not get angry, does not get careless, does not carry out vendettas. It is nothing personal.

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Blogger IConrad said...

By the logic that the methane clathrate is an impending ecological disaster, doesn't it make more sense to burn off as much of it as humanly possible before some disruption occurs?

After all, we'd be converting the strong greenhouse gas into a weak greenhouse gas -- CO2 -- that we could then sequester in non environmentally-vulnerable locations.

But of course, eco-fundamentalists don't think that way. Energy = bad.

There *was* an epoch which did have clathrate triggering -- not the Jurassic die-off (might have the period wrong) but rather a pre-dinosaurian die-off. I don't remember.

Thursday, 27 December, 2007  
Blogger al fin said...

Yes, I agree. Using the methane as a clean fuel makes more sense than waiting for it to be released catastrophically from volcanic action, seismic action, or asteroid strike.

Undersea methane is actually under the seafloor. It is not entirely clear whether the methane comes from deep in the earth, or if it is a result of microbial degradation of organic matter--trapped under layers of sediment. Perhaps both.

Methane is abundant in space, on other planets in the solar system, etc. Much of earth's undersea methane may be residual methane from the time of planet formation.

It is easy to conceive of a large dome/inverted funnel structure anchored to the seafloor surrounding an undersea drilling site, to catch the released methane. Or mine the clathrates in frozen form, but use the inverted funnel to catch accidental gas leakage.

Friday, 28 December, 2007  

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