This is kind of some weird science. Most of you are familiar with methane. It's the gas that comes out of your kitchen stove. 7-10% of the gas that comes out of farts is comprised of methane. Methane is obviously a gas, and it's not very easy to liquify. (Even dry ice isn't cold enough to liquify it.) And unlike propane, it's impractical to try to use pressure to liquify it. (Even 1000 atmospheres of pressure in a Siberian Winter is only enough to just start liquifying a portion of it.) Nevertheless, methane is stored in the Earth. Methane has the capability to combine with water in a way that allows it to be stored more easily. No, if you try to mix methane with water you won't see anything magical happen. The magic happens deep under the oceans, at crushing depths with high pressures and cool temperatures. This solid methane exists in the form of something called a clathrate, where the crystal structure incorporates both molecules of methane and water. You can see a cube of this substance burning in this video: This clathrate exists in clay layers beneath the ocean floor. Unlike regular ice, the solid methane-water complex stays solid up to 57 degrees F under the immense pressures at the ocean floor (80 atmospheres). Over 90% of the ocean floor is below 42 degrees F. This has big implications for global warming, since as temperatures rise, a larger percentage of the ocean floor is no longer cool enough in temperature to sustain methane in its solid clathrate form and more methane will be released. Methane is a much more potent greenhouse gas than carbon dioxide, more than 6 times as much.