Methane Hydrates
Methane hydrate is methane found under seabeds and permafrost. It is methane trapped in a crystalline structure similar to ice. This methane source has a positive feedback loop in regards to climate change. That is, with the climate warming more methane hydrate melts, releasing more methane previously sequestered and contributes further to climate change.

(CC Image courtesy of NASA Earth Observatory on Flickr)





