How about we modify pigs to store methane instead of releasing it? And then we'll use DNA surgery to graft wings on them so their huge, inflated bodies can still maneuver around.
Then we'll be ready for that inevitable Global Warming, as both events will come about at the same time.
I think I have a better solution--what if we train the pigs to "plug" themselves into a gas recovery system, kind of like self milking cows, when they need to release?
Pigs are real smart, you know.
But then again, pigs floating around in the atmosphere would provide additional radiation shielding, and if we tether them, after awhile you would just have to reel one of them in to enjoy some barbecued spare ribs.