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scpg02
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Study reveals lakes a major source of prehistoric methaneStudy reveals lakes a major source of prehistoric methane
Submitted by Marmian Grimes
Phone: 907-474-7902
10/24/07
| Quote: | A team of scientists led by a researcher at the University of Alaska Fairbanks has identified a new likely source of a spike in atmospheric methane coming out of the North during the end of the last ice age.
Methane bubbling from arctic lakes could have been responsible for up to 87 percent of that methane spike, said UAF researcher Katey Walter, lead author of a report printed in the Oct. 26 issue of Science magazine. The findings could help scientists understand how current warming might affect atmospheric levels of methane, a gas that is thought to contribute to climate change.
“It tells us that this isn’t just something that is ongoing now. It would have been a positive feedback to climate warming then, as it is today,” said Walter. “We estimate that as much as 10 times the amount of methane that is currently in the atmosphere will come out of these lakes as permafrost thaws in the future. The timing of this emission is uncertain, but likely we are talking about a time frame of hundreds to thousands of years, if climate warming continues as projected.”
Ice cores from Greenland and Antarctica have shown that during the early Holocene Period--about 14,000 to 11,500 years ago--the levels of methane in the atmosphere rose significantly, Walter said. “They found that an unidentified northern source (of methane) appeared during that time.”
Previous hypotheses suggested that the increase came from gas hydrates or wetlands. This study’s findings indicate that methane bubbling from thermokarst lakes, which are formed when permafrost thaws rapidly, is likely a third and major source.
Walter’s research focused on areas of Siberia and Alaska that, during the last ice age, were dry grasslands atop ice-rich permafrost. As the climate warmed, Walter said, that permafrost thawed, forming thermokarst lakes. |
http://www.uaf.edu/news/news/20071024130833.html
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Andre
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Thanks Maggie, there is an essential part of the glacial transition story here to be uncovered. But one thing is easily debunked, it could not have and it did not cause significant additional warming due to greenhouse effect as can be seen here, using some modtran runs:
As can be seen in the lower left corner, not much going on with methane.
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