I had a wild-eyed theory that the hydrates degassed when the sea level dropped during Ice Ages (less hydrostatic pressure), and provided enough methane to start the warming cycle.
Hmm. Interesting theory. the earth has a lot of feed-back loops. Of course the hydrates releasing in a catastrophic is one of the theories behind the huge Permian(?) extinction millions of years ago.
Yep - hopefully Japan will make great progress on drilling them to release the pressure s-l-o-w-l-y!