There have not been reports of the sea turning to bubbles and visual sightings of ships foundering, as there would be if it was a documented fact. It's theory only, and being a nasty suspicious individual, unless it is confirmed by eyeball and witnessed, I'm afraid it just don't exist! The Cameroon lake is volcanic CO2, not methane. It is little more than pie in the sky I'm afraid. At this stage of scientific development, if it existed, we'd have proof by now. It serves no more function now than to get these people wearing metal foil skull caps.