Watching An Inconvenient Truth last night, amazed to learn about vast pockets of methane trapped under permafrost in Siberia — pockets that are increasingly being released into the atmosphere as the permafrost melts due to global warming. Since methane is a greenhouse gas, the releases are yet another “vicious cycle” contributor to global warming: more warming = more permafrost melting = more methane released = more warming.
Talking later about this cycle, Dad alerted me to theories about methane’s possible role in the mystery of the Bermuda Triangle. When methane pockets beneath the ocean floor are released (by excess pressure or the ocean floor being broken by seismic activity) they bubble up in huge columns. The column of bubbles have far less buoyancy than normal water, and a ship sitting atop one of these columns could literally plummet to the bottom of the sea (indeed, ships have been found at the bottom of the sea nestled into craters that could be explained by methane releases).
In addition, concentrations of less than 1% methane in the air has been shown to be capable of stopping piston engines in their tracks, due to oxygen starvation – which could account for the downing of airplanes in the area of a methane release (not sure how this would play out for jet engines).
There seems to be quite a bit of credible accounting for the theory out there, but also a fair bit of debunking. Not ready to call this one solved, but it is an intriguing theory.