Climate: the methane time bomb is triggered 25 September 2008
Scientists have found evidence that the Arctic seabeds are beginning to release millions of tonnes of methane, a greenhouse gas 20 times more potent than carbon dioxide, into the atmosphere. The researchers were able to observe the bubbling caused by the gas on the surface of the sea.
By Steve Connor, The Independent, 23 September 2008
The Independent has taken note of some of the early results, which suggest that methane gas in huge arctic deposits is escaping to the surface due to warming and disappearing ice.
The behavior of these underground methane reserves is of major importance because scientists believe that their sudden release into the atmosphere has caused a rapid increase in Earth's temperature in the past, causing climate disruption and even a massive extinction of species. . Scientists aboard a scientific boat that has sailed all over Russia's northern coast have found intense concentrations of methane - sometimes up to 100 times usual levels - over several areas, covering thousands of square kilometers on the Siberian continental shelf.
In recent days, researchers have observed areas where the sea was bubbling with gas bubbles rising from "methane chimneys" emerging in the seabed. They believe that the layer of underwater permafrost that acts as a "lid", preventing gas from being released, has melted in places and allows methane to escape from the deposits that formed before the last ice age .
Researchers caution that this phenomenon may be related to the rapid warming experienced by the region in recent years.
Methane is a gas whose greenhouse effect is about 20 times more powerful than carbon dioxide and many scientists fear that its release could accelerate global warming through a huge feedback process in which the methane released into the atmosphere would cause higher temperatures, which would worsen permafrost melt and release more gas.
It is estimated that the amount of methane trapped under the Arctic is greater than the total amount of carbon contained in global coal reserves. It is therefore of utmost importance that these reservoirs remain stable as this region heats up at a faster rate than other parts of the earth.
Orjan Gustafsson, one of the leaders of the expedition, describes the extent of methane emissions observed in an enamel sent from the Russian scientific ship Smirnitskyi Jacob.
"We worked feverishly to complete the sampling program yesterday and last night," Dr. Gustafsson writes. "A large area of intense methane release has been discovered. On the previous sites we observed high concentrations of dissolved methane. Yesterday, for the first time, we observed an area where the release is so intense that methane has not had time to dissolve in seawater, but arrives in the form of methane bubbles on the surface. These "methane chimneys" were observed on echosounder and with seismic [instruments]. "
In some places, methane concentrations reached 100 times usual levels. These anomalies were found in the eastern Siberian Sea and the Laptev Sea. They cover tens of thousands of square kilometers, and add up to millions of tonnes of methane, Dr. Gustafsson said. "This could be of the same order of magnitude as is currently estimated for all oceans. He says. "Nobody knows how many other areas exist on the great continental shelf of eastern Siberia.
"The usual assumption was that the permafrost" lid "on the submarine sediments of the Siberian continental shelf could retain these enormous deposits of methane. The increase in methane release observations in this inaccessible region may suggest that the permafrost, the cover, is beginning to be punctured and thus is leaking methane ... Permafrost now has small holes. We found high levels of methane above the surface of the water and more in the water just below. It is obvious that the source comes from the seabed. "
Preliminary results from the Siberian Plateau study 2008, being prepared for publication by the American Geophysical Union, are supervised by Igor Semiletov of the Far East Department of the Russian Academy of Sciences. Since 1994, he has led about 10 expeditions in the Laptev Sea. During the 1990 years, it had not detected high levels of methane, but since 2003, it has reported an increase in the number of "hot spots" of methane, which are now confirmed by the more sensitive instruments that are present aboard the Jacob Smirnitskyi.
Dr. Semiletov suggests several reasons why Arctic methane now escapes, including the increase in the volume of the relatively warmer waters that are discharged from Siberian rivers due to the melting of terrestrial permafrost.
The Arctic region as a whole experienced a rise in average temperatures of 4 degrees Centigrade over the last few decades, with a dramatic decline in the area covered by pack ice during the summer. Many scientists fear that the disappearance of pack ice can not accelerate the global warming trend because the ocean absorbs more heat from the sun than does the reflective surface of the ice.
On the Web :
La personal pageby Orjan Gustafsson on the website of Stockholm University
Le Devoir, Canada: The methane bomb is primed
Joined yesterday at his offices at the Institute of Marine Sciences of Rimouski, Professor Émilien Pelletier, a marine chemist and ecotoxicologist, sees this phenomenon as "the extension in the marine environment of what happens in the terrestrial permafrost". If Swedish scientists announce the start of a submarine permafrost thaw, he says, humanity should expect a massive release of greenhouse gases that could trigger the climate in a potentially irreversible change .
Methane hydrates, he says, are present in many large seas. Under the effect of very cold water and unimaginable pressures of great depths, the bottom, the methane sometimes solidifies in the form of huge crystals. Commercial companies even seek to exploit these fuels stored at great depth.
In the Arctic seas, another phenomenon seems to occur, he says, according to the findings reported by The Independent.
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Start building your troglodyte dwellings!
yahi
Oops, not good ....
but I have pilots in my family and so I knew other pilots, elders, who told me the same thing: there is a considerable increase in cloudiness since the 60 / 70 years.
