There's something lurking deep under the frozen Arctic Ocean, and if it gets released, it could spell disaster for our planet. That something is methane.
Methane is one of the strongest of the natural greenhouse gases, about 80 times more potent than CO2, and while it may not get as much attention as its cousin CO2, it certainly can do as much, if not more, damage to our planet.
That's because methane is a far more potent greenhouse gas than carbon dioxide, and there are trillions of tons of it embedded in a kind of ice slurry called methane hydrate or methane clathrate crystals in the Arctic and in the seas around the continental shelves all around the world.
If enough of this methane is released quickly enough, it won't just produce the same old global warming.
It could produce an extinction of species on a wide scale, an extinction that could even include the human race.
If there is a "ticking time bomb" on our planet that could lead to a global warming so rapid and sudden that we would have no way of dealing with it, it's methane.
Right now, estimates suggest that there's over 1,000 gigatons - that's a thousand billion tons - of carbon in methane form trapped just under the Arctic ice. And if stays trapped under the ice, we might have a chance.