Pardon the pun, but one of the more hotly debated ideas about mass extinctions is whether or not giant methane "burps" in Earth's past have been responsible for causing runaway global warming and wiping out huge chunks of life.
Argentinian geologist Rodolfo del Valle has found a similar belch going on right now in Antarctica, albeit on a smaller scale. Gases bubbling up from the seafloor are turning parts of the waters off the Antarctic Peninsula into a noxious Alka-Seltzer, potentially worsening global warming and even killing local wildlife.
The tricky thing is, no one really knows how dangerous the frozen methane ice is. We know there's a lot of it, probably trillions of tons, locked in near-freezing temperatures of continental shelves around the world. If it all burst into the atmosphere at once, the effects on climate would be catastrophic.
What we don't know is just how unstable the "clathrate" deposits are. How much warming of the deep ocean will it take to set off this carbon bomb? Are they already starting to explode?