Clathrate (hydrate) gun hypothesis stirred quite the controversy when it was posed in 2003. It stated that methane hydrates – frozen water cages containing methane gas found below the ocean floor – can melt due to increasing ocean temperatures.
Scientists have calculated that the present day ice sheets keep vast amounts of climate gas methane in check. Ice sheets are heavy and cold, providing pressure and temperatures that contain methane in form of ice-like substance called gas hydrate. If the ice sheets retreat the weight of the ice will be lifted from the ocean floor, the gas hydrates will be destabilised and the methane will be released.Studies conducted at CAGE have previously shown that ice sheets and methane hydrates are closely connected, and that release of methane from the seafloor has followed the retreat of the Barents Sea ice sheet some 20,000 years ago. But is all such release of the potent climate gas bound to be catastrophic?Not necessarily, according to a new study published in Nature Communications. It shows that the methane was indeed released as the ice sheets retreated. However the seepage did not occur in one major pulse, but over a period of 7000 to 10000 years following the initial release.