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Comment by rexaliquid | Hacker News Reader

The Clathrate gun hypothesis and the thawing of the Arctic ecosystem are two of the "Four Horsemen of the Apocalypse" that the US government investigates. These are possible scenarios for abrupt climate change (aka tipping points). The other two involve antarctic ice sheet instability and megadroughts in North America.

http://newscenter.lbl.gov/2008/09/17/impacts-on-the-threshol...

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Sounds very similar... Or at least variations of the same idea.

It's definitely not the same problem. Clathrates are methane, for one thing, and the permafrost issue will cause CO2 emissions. Clathrates are in the water, permafrost is soil.

They are both associated with historically cold environments that are now warming up, but each has its own mechanism and likely impacts (clathrates may be worse, since methane is a much more powerful greenhouse gas, but the permafrost melting is going to be with us for 1000's of years whereas methane will be with us for "only" a decade. Also permafrost is likely to be a potent methane producer as well while it thaws out.

What does "be with us" mean in the case of methane?

Methane turns into CO2 and water vapor over time as it reacts with other stuff in the air. It takes about 10 years for atmospheric methane to turn into something other than methane.

Yep. The caveat is that we are currently adding methane at a faster rate than it is lost through this process, which obviously means methane concentrations are increasing right now, and early signs are that this may accelerate. Sigh.

They are both examples of positive feedback loops that result in abrupt changes to the climate, yes. But, because they are different systems, the feedback loops behave differently. Methane trapped in sea ice is studied and modeled separately from organisms frozen in arctic permafrost.

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