Thu Dec 3rd, 2009 at 09:54:05 PM EST
With the Copenhagen Climate Conference rapidly approaching and with the emphasis on CO2 emissions, it seems timely to review the potential impact of the other major greenhouse gas, methane.
Katey Walter Anthony, an aquatic ecologist and a biogeochemist with a list of academic publications going back to 2005, is a research professor working with the Water and Environmental Research Center at the University of Alaska Fairbanks. She studies the permafrost in Alaska, Canada and Russia. She is also involved in "Outreach & Education" appearing on programs and in articles on NPR, the BBC, National Geographic, Nature and Scientific American.
I encountered her in the December 2009 issue of Scientific American, to which, unfortunately, I do not have on line access. From the various descriptions of her work and activities it seems that the lady is fearless. May she remain so. This diary is comprised of quotes and summaries of various of these above links and other articles.
- Methane has more than 20 times the potency of CO2 as a greenhouse gas.
- Close to a trillion tons of carbon are currently stored in the top several tens of meters of the 20% of the earth's surface that is permafrost.
- As permafrost thaws microbes decompose organic remains producing methane that can be released into the atmosphere.
- One third to one half of permafrost is now within 1 to 1.5C of thawing.
- At currently predicted rates of thaw 20 to 40% more methane will be released into the atmosphere than from all other natural and man-made sources.
- This could produce a further 0.32C increase of the earth's mean annual temperature compared with current projections.
- More than one trillion tons of methane hydrates are estimated to lie at depths of hundreds of meters below the ground or sea floor. 10% of that released into the atmosphere would be twice the estimated 50 billion tons of methane that is estimated to potentially be released by permafrost thaw. There is no evidence that hydrates are being released at present.
Russian scientists were the first to investigate the phenomenon of methane bubbling out of lakes in Siberia in the summer. US scientist Katey Walter performed the research for her PhD in Siberia beginning in 2000 studying these emissions. She has systematic measured the methane emissions of numerous lakes and is involved in several collaborations to estimate positive and negative feedback loops and to provide maps based on remote sensing to estimate methane and carbon dioxide emissions in permafrost regions from 21,000 years ago to the present.
Laurance Plug of Dalhousie University in Nova Scotia and a post-doc, Mark Kessler are developing two computer models, one will simulate the dynamics for a single lake and the other is a landscape model that will simulate the dynamics of a lake basin. These models will have to be validated against current and historical data from cores going back 15,000 years in Siberia and Alaska.
The final step will be to integrate these models into the Hadley Center Coupled Model that describes the circulation of the oceans and the atmosphere and that is a major model used in IPPC assessment reports. At present she is concerned that the effects of Arctic methane release are not well covered in this model. She has also a co-author of "Global Methane Emissions From Wetlands, Rice Paddies, and Lakes", EOS, Transactions, American Geophysical Union, 90 (5): 37-44. by Zhuang, Q., J. M. Melack, S. Zimov, K. M. Walter, C. L. Butenhoff, and M. A. K. Khalil, 2009, "Emerging Challenges. Methane from the Arctic: Global warming wildcard. United Nations Environmental Program, An overview of our changing environment" Melillo, J. F.S., R. Corell, K.M. Walter, Chapin, III, D. McGuire, , UNEP Year Book 2008, Editor Paul Harrison, Division of Early Warning and Assessment (DEWA), Nairobi, Kenya, and "Potential use of synthetic aperture radar (SAR) for estimating methane ebullition from arctic lakes" Walter, K. M., Duguay, C., Jeffries, M., Engram, M., and Chapin III, F. S., 2008, , Journal of the American Water Research Association, 44(2):305-315.http://www.alaska.edu//uaf/cem/ine/walter/publications_docs/Walter_JAWRA2008.pdf among others.
From a biographic sketch on National Geographic's web site Dr. Katey Walter Anthony explains the significance of streams of bubbles emerging from Arctic lakes:
"The bubbles are methane, a strong greenhouse gas that's 25 times more powerful than carbon dioxide," Walter Anthony explains. It's being released at an accelerating rate from thawing permafrost, frozen soil that holds vast amounts of carbon. When the Earth's rising temperatures cause it to suddenly thaw, lakes form. "All that carbon was locked up safely in the permafrost freezer for tens of thousands of years," Walter Anthony says. "Now the freezer door is opening, releasing the carbon into Arctic lake bottoms. Microbes digest it, convert it to methane, and the lakes essentially burp out methane."
Scientists estimate that permafrost holds up to 950 billion tons of carbon. As it thaws, 50 billion tons of methane could enter the atmosphere from Siberian lakes alone. "That's ten times more methane than the atmosphere holds right now," Walter Anthony notes. "Since methane traps heat so efficiently, temperatures will rise higher, faster." In the atmosphere methane spreads rapidly too, circling the globe in just one year.
An interview with Walter Anthony that demonstrates some research methods:
Walter Anthony has also been known to employ simpler means of verifying the presence of methane below frozen lakes. Here is an example of what happens:
Some of her "Outreach & Education" efforts will undoubtedly be criticized by those "doubting" climate change and global warming. But I think they are important to raise public awareness of the issue.