Methane is a more powerful greenhouse gas than CO2, but methane decomposes relatively quickly into CO2. The main concern about methane release is thus the CO2 which, unlike methane, remains in the atmosphere for centuries. Although unlikely, a "runaway" or "catastrophic" impact of methane release has not been completely ruled out as a future possibility, and may have happened in the pre-human past.

http://www.realclimate.org/index.php/arc...

http://en.wikipedia.org/wiki/Runaway_cli...

Edit: DaveH here asserts that we are "quite safe" but (as typically) cites no sources. There are in fact quite a few scientific details about climate change that are not clear. What might happen with the methane deposits beneath the sea floor is one of them. The fundamental longstanding consensus of top scientists (that DaveH and many others here too deny, as did the fossil fuel industry before them), regarding the basic situation with climate change, is however quite clear and solid:

U.S. National Academy of Sciences, 2010:

http://books.nap.edu/openbook.php?record...

“Climate change is occurring, is caused largely by human activities, and poses significant risks for a broad range of human and natural systems.”

http://www8.nationalacademies.org/onpine...

“Choices made now about carbon dioxide emissions reductions will affect climate change impacts experienced not just over the next few decades but also in coming centuries and millennia…Because CO2 in the atmosphere is long lived, it can effectively lock the Earth and future generations into a range of impacts, some of which could become very severe.”

http://www.physics.fsu.edu/awards/NAS/

“The Academy membership is composed of approximately 2,100 members and 380 foreign associates, of whom nearly 200 have won Nobel Prizes. Members and foreign associates of the Academy are elected in recognition of their distinguished and continuing achievements in original research; election to the Academy is considered one of the highest honors that can be accorded a scientist or engineer.”



http://www.aps.org/publications/apsnews/...

http://www.aip.org/history/climate/timel...

http://www.aip.org/history/climate/index...

Edit 2: Whether it's a statement from the U.S. National Academy of Sciences or a map of the British Isles, any of the many things JimZ here is incapable of understanding or unwilling to try to learn about, must, according to his abiotic oil geology expertise, come from "left wing blogs."

Methane is 50 times more powerful than CO2 as a greenhouse gas. The result of a rapid release of methane would not be catastrophic in terms of climate. It would take many years to influence climate. Climate is not measured under 30 years, weather is.

A huge release of methane from the seabed would be catastrophic in other ways. It would change the pH of the worlds oceans. That would kill a lot of sea life which would have a knock on effect, up the food chain, to higher mammals. The sudden release of methane hydrates has been implicated in at least 2 of the 5 major extinction events our planet has experienced. But not because of its impact on weather or climate.

Well Methane is already being released off the Arctic sea floor and will likely result in a positive feedback loop between GW, rising ocean temps and the release of Methane from Methane Hydrate off the sea floor similar to the positive feedback loop from the calcium carbonate in the ocean releasing CO2 via wave action The more heat, the more Methane released from the ocean floor.

There is always a chance of runaway GW, but Methane is not the only thing making this possible. I don't believe we will see any runaway from sea floor Methane unless we do nothing about fossil fuel burning I do not subscribe to any model projections, but we are still warming disregarding the BS being spewed by the DA deniers about any pause or halt of GW warming. In this case specifically, funny how denier rhymes with lier.

I have read that Methane is @ 23 times more powerful as a greenhouse gas than CO2 so I believe it has a more immediate effect in the area where it is released causing a greater warming. This in conjunction with the Methane released due to the Greenland Ice Shelf and Russian Permafrost melt of the land surface may well be why the Arctic temps have been rising twice as fast as the rest of the planet.

Assuming that the ocean warmed significantly, it would release that methane hydrate that was no longer stable under the new conditions. That methane would rise to the atmosphere where it is a more potent GHG but it would rapidly convert to CO2 in the atmosphere. If the models of AGW are correct, this might lead to warming which leads to more catastrophic release which leads to more warming etc. I think the theory has been pretty much debunked and it is considered very unlikely by most experts.

IMO, Dave is the only informed answer after me, at least the three after me are ill informed. They obviously get their information from left-wing blogs like skepticalscience that is neither skeptical nor about science. That is why they are so confused about actual science.

It can cause a lot of warming. This could be what would cause dramatic sea level rise. It will not lead to Earth turning into Venus. I don't know what Mister Zedd thinks has been debunked.It is IPCC science that says that says that you can have positive feedback without runaway warming.

http://www.skepticalscience.com/positive...

Regarding DaveH's response, Earth having been much warmer in the past would be evidence that IT COULD HAPPEN. It probably did happen at the end of past ice ages, which is not the same as the beginning of interglacials.

I doubt that it happened at the beginning of interglacials during the current ice age. Ice core samples do show a strong correlation of methane with temperature, but I don't think that the methane spikes were as large as would be expected in the case of a large scale methane hydrate release.

I find it funny how denialists think that just because life survived past warmer conditions means that rising sea levels either won't happen or won't be bad. None of the plagues, tsunamis, earthquakes, floods, tornados, hurricanes or wars have wiped out all life on Earth. But who wants to go through any of these?

'Could' result.

Actually, we know this won't happen. If this 'could' happen then it would have happened in our past. The earth has had oceans and been warmer in the past. But it did not lead to runaway heating due to ch4 release.,We are quite safe.

I need not worry about global warming caused God promised Noah that he would not destroy the world again by flood