Methane hydrate releases

There are 5 other identified methane releases from the fossil record.

You need to have a period of cold first to sequester the methane, or so they say.

Interesting.

(Edit: crap, I don't know who said this! I think it was J. Kiehl of NCAR, but I really don't remember. This is at the CCSM Paleo Climate Working Group meeting).