That will cut methane emissions way back.

Seriously, it is a problem. Other chemicals are even more effective. The residence time in the atmosphere is the key factor. Methane is oxidized by air. Carbon dioxide is not.

Methane is found in abundance as hydrates on the ocean floor. Warming of the sea may cause its release, resulting in more heat, more methane, etc in a positive feedback loop.

Let's face it, in the face of economic necessity nobody is going to anything about greenhouse gases except pretend stuff like the Kyoto accords. Money rules. If the businessmen of the World KNEW, for sure, that byproducts of their activity would exterminate all human life in a couple of hundred years, they would not change one iota of what they are doing. This year's, this quarter's profits are all that matter.

Since nobody is going to do anything, why bother to bring it up?