Companies looking for ways to cut greenhouse gasses are also searching for ways to trade cutting them somewhere else if it's cheaper or more feasible than cutting their own. Sometimes they think outside the box...
It should be noted that while methane is I think even more of a heat trapper than water vapor (another powerful one that quite puts carbon dioxide in the shade, warmingwise) it is also impermanent in atmospheric conditions -- it lasts about nine years at most and UV breaks it down into smaller stuff, reacts with oxygen, and so on.
Water vapor we can't control, it's always been a factor. The concern is man added stress on the natural cycles. It doesn't matter how fast it breaks down if we're adding it faster than it deterioerates.
Not only has water vapor been a factor, we'd look like glacial planet Hoth without its heat blanket.