Gas clathrate hydrates are ice-like solids, in which gas molecules or atoms are trapped inside crystalline frameworks formed by water molecules. They have attracted considerable attention over the last decade for their potential as a geo-organic fuel resource, as they naturally form in large quantities within marine sediments and below continental permafrost. Exchanging the guest gases in existing methane hydrate deposits with CO2 has also been recently indicated as a promising two-in-one approach of energy recovery and concomitant carbon dioxide mitigation.