A Few Things Ill Considered

Good news, bad news

Well, the good news is a recent finding of 740,000 year old permafrost in the Canadian arctic. What this suggests is that the permafrost may be more resilient than previously thought. If this ice is 740Kyr old, then it did not melt during the last three inter-glacial cycles. The peak warmth of at least the Eemian, 120Kyr ago, was a couple of degrees warmer than now, and some serious effort might keep temperatures from rising above that high marker.

The reason this is good news is because of the large (huge) quantities of methane stored in clathrates in this permafrost. If released, this would represent a very large feedback, and frankly all bets would be off as to how drastically the climate might change. CH4 (methane) is 22 times as powerful as CO2 as a greenhouse gas, and there is lots of it!

So the encouragement comes from a renewed hope that this feedback may not kick in and kick us in the collective rear-end.

The bad news?

It seems another similar feedback may already be underway.

The first evidence that millions of tons of a greenhouse gas 20 times more potent than carbon dioxide is being released into the atmosphere from beneath the Arctic seabed has been discovered by scientists.

The Independent has been passed details of preliminary findings suggesting that massive deposits of sub-sea methane are bubbling to the surface as the Arctic region becomes warmer and its ice retreats.

You see, permafrost is not the only source of methane, and not even the largest. The sea floor sediments are just chock full of methane clathrates. Sudden release of sub-oceanic methane is the prime suspect in more than one sudden climate change. 55 million years ago, the Paleocene-Eocene Thermal Maximum (PETM) saw temperatures soar some 6oC in something less than **20,000 years, maybe less but the resolution of sediment proxies is not good enough to know better. (We may well be on the way to doing this in 200!)

I’d have to say in this case, the bad news definately outweighs the good…

**the 20k yr figure comes from the wikipedia article and while I am sure it is a well supported number, I seem to recall not too long ago some new research suggesting this all may have happened much faster. The limitation on figuring this out is due to the coarse temporal resolution of the different proxies. ie the layers of mud they dig up are too thin!

Comments

  1. #1 William
    September 24, 2008

    Don’t be too sure that the PETM wiki article is well written or watched

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