Methane Bubble in Gulf?

Doomsday 'mega-bubble' theory debunked

click "debunked" above to read full news article. quote from article follows begin quote

You're now probably wondering if it's time to start frantically compiling a bucket list of things to do before we're all killed off by a methane eruption. However, according to an expert interviewed by Yahoo! News, such doomsday predictions are "extreme" and highly unlikely to take place.

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The main reason that even if such a methane bubble exists that it likely won't be a threat is simply that methane after it reaches the surface in a gaseous (not liquid or frozen) state goes straight up into the upper atmosphere because it is lighter than air. However, propane is not so when there is a propane leak it will gather along the ground and I saw during my teen years an explosion in the city of Yucca Valley of a major propane explosion where it basically leveled a block and shot an explosion several hundred feet into the air and could be heard for at least 25 to 50 miles away.

So, Methane because it is lighter than air will not gather on the surface unless it is in a frozen or liquid state. And I believe that it very soon would covert into a gas and be airborne. Also, I doubt if it could be ignited in a liquid or frozen state. However, I'm not sure about that.

However, if such a bubble of methane were high in the atmosphere and didn't dissipate and mix in all over the world eventually I'm not sure about the short or long term consequences of that much methane in the upper atmosphere of earth.