How big of a runaway climate threat is methane hydrate

Great Debates
1

Reading this article today was pretty bothersome.

http://news.bbc.co.uk/2/hi/science/nature/8437703.stm

A trillion tons of methane is trapped in permafrost near Siberia, and global warming is possibly loosening it. I have heard the same problem exists in other parts of the world with methane that is trapped. As global temps go up due to CO2 it could cause the release of methane and create a massive positive feedback loop.

I’ve heard of this problem before, but didn’t know how severe the issue was until I read the article (I thought it was expected to be more of a slow release)

So, questions:

  1. How long would this feedback loop take (years, decades, centuries, etc). I have heard it could result in large amounts released rapidly, and I’ve heard it’ll be a slow release and much of the methane will leak and convert to CO2 (which is far less damaging).

  2. Can it be stopped when it begins? Can the pressure be increased or the temperature decreased to keep the methane trapped?

  3. How high of a risk is it that a positive feedback loop will begin (warming leads to the release of methane, which leads to more warming which leads to more methane)

2

Well, it could be worse than just warming…can you sayPermo-Triassic Extinction? I thought you could.
And to answer you questions:
1)I’d guess on the order of decades to centuries, given atmosphere turnover rates (i.e. not in just a year or less)
2) Nope, if the feedback starts, I don’t think we really have the tech. to stop it.
3) Pretty high, but not inevitable, I’d say. I mean, the stuff is outgassing even as I type, in larger amounts than historically, AFAICT.

3

eta: to clarify (1), I personally think the rates are in the order of 1 000 yrs and up, because the atmosphere/seabed system is so slow to react. However, I’ve been reading that this possibly isn’t the case with the Arctic clathrates (I’m more familiar with Gulf and continental shelf clathrates from the literature)