Is there any significant geo-hazard associated with dissociating gas hydrate on continental margins (excluding the facts such as (a) methane is 21 times more powerful greenhouse gas than CO2; (b) destabilization of natural gas hydrates resulting from an elevated mean global temperature)?
I would add that a third geo-hazard associated with dissociating gas hydrates, beside the two mentioned by Suresh, is likely to be large submarine landslides along the continental margin (such as the Storegga mega-slide off the coast of Norway) and the associated tsunamis.
Quoting Dr. Jannifer Stanford (from http://www.bbc.com/earth/story/20160323-the-terrifying-tsunami-that-devastated-britain), "In the last 45,000 years, about 70% of all continental slope failures off western Norway occurred during the period of most intense deglaciation: from 16,000 to 4,000 years ago", and "Ocean warming might lead to the melting of the gas hydrates in the ice that contain methane that then ultimately can destabilise sediments.".
The literature has many articles on the Storegga submarine mega-slide and its possible triggering by gas hydrate melting. See for example:
https://www.sciencedirect.com/science/article/pii/S0025322706000703
Chapter Gas Hydrates at Storegga Slide
and many others.
NF3 is 17,000 times more efficient than CO2. And? We still believe that solar panels are "green".
As for your question, underwater gas-hydrate systems are extremely stable (on PT diagram) not only because the bottom water temperature is stable +4 C, but also because of water column pressure and its increase for the believed rise of water level. 1 cm ~ 0.001 bar.
Since CH4-hydrates destruction in endothermic reaction - hydrates have self-conservation feature. So again, they are stable. Don't worry.
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