[bruinbirdman]

"The trouble is that mining methane ice is very risky, as it is close to the temperature of sublimation, and the entire methane ice field could have a chain reaction . . . This would be bad."

IIRC earth's original atmosphere was mostly methane. It took billions of years for it to dissolve and settle to the ocean floors resulting in the unique atmosphere we have now.

The methane ice layers are not a new descovery. You are correct that it has been left alone for fear of disrupting such a fragile, ancient and life supporting ecosystem.

yitbos

[yefragetuwrabrumuy]

Yet there are strong suspicions that unpredictable, such undersea fields of methane ice can erupt.

http://www.dailymail.co.uk/sciencetech/article-2073686/Fountains-methane-1-000m-erupt-Arctic-ice—greenhouse-gas-30-times-potent-carbon-dioxide.html

[SunkenCiv]

For methane on the ocean floor to have a “chain reaction” (meaning combustion, apparently), would require the presence of oxygen. There is none down there. Thanks bbm.