4 responses

1. 

   DocBud

   June 6, 2007

   “Yet two degrees – we are already at 0.7 degrees – is widely recognised as the threshold of unacceptably dangerous change. It could mean the loss of the Greenland and west Antarctic ice sheets, and a rise of seven metres in sea levels – a catastrophe for delta cultures such as Bangladesh and the Netherlands.” I don’t think anyone is saying a further 1.3 degrees will do this anytime.
   The following paper suggests the methane/permafrost fears have been overstated:
   http://www.agu.org/pubs/crossref/2007/2007GL029323.shtml

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2. 

   Kit

   June 6, 2007

   He is also out of date with his “thawing permafrost” theory.
   “HANOVER, Germany, May 21: German scientists re-examining projected melting of Arctic permafrost from global warming say massive releases of methane are unlikely this century.
   Scientists say as the Earth’s climate warms, permafrost will continue melting and methane bound in frozen sediments could escape into the atmosphere. Because methane is a greenhouse gas, that would exacerbate global warming.
   One permafrost model, presented in late 2005, indicated near-surface Arctic permafrost would completely degrade during the 21st century. But Georg Delisle and colleagues at the Federal Institution for Geosciences and Natural Resources in Hanover offer an alternative model designed to have a more complete mathematical formulation of the physical processes in permafrost.
   The German researchers note that ice-core analyses previously made by other scientists indicate minimal release of methane during warm periods occurring during the last 9,000 years.
   Based on the new model and the ice-core findings, Delisle concluded that scenarios calling for massive releases of methane in the near future from degrading permafrost are questionable.
   The research is detailed in the journal Geophysical Research Letters.”

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3. 

   Kay Tie

   June 6, 2007

   CH4 is 23 times more greenhousey compared to CO2 – molecule for molecule. Weight-for-weight that’s a factor of 7.

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4. 

   Brad Arnold

   June 11, 2007

   Frankly, I think people are too relaxed about the melting of the cryosphere. Particularly, methane hydrate, that contains more carbon than all the oil, coal, and natural gas reserves in the earth. Briefly, it is created by microbes that “digest” carbon in the absence of oxygen, which then emit CH4. Some gets trapped in ice called hydrate-there is an estimated 400 billion tons of methane trapped in permafrost hydrate, and about 10,000 billion tons trapped under the seas. A sudden release of less than 30 billion tons would be like doubling the CO2 in the air.
   By the way, our greenhouse gas emissions are about 30 times more than the trigger to the last runaway global warming episode 55 million years ago (the PETM). Our emissions will melt the cryoshere, which will in turn warm up the world enough to start melting the massive oceanic methane hydrate reserves. The stronger the trigger, the sooner the chain reaction starts, the faster the chain reaction proceeds, and the much much more severe the episode (i.e. CH4 oxides in less than ten years into the much less warming CO2, but which stays in the air hundreds of years).

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