Frozen Methane
The Guardian has a series of photos of frozen methane in Canada. If released into the atmosphere, methane creates 20 times more greenhouse emissions than burning petroleum. If lit, however, its byproduct is water: it’s the cleanest form of hydrocarbon you can get. The problem is condensing & pressurising it in a cost-effective way. If we can achieve that, we have another source of fuel that will last us longer, and reduce our emissions to nearly nothing.
A lake of frozen methane bubbles