Methane release around Arctic islands predates recent climate change

Precipitated carbonate at one of the sites of methane seepage.

GEOMAR

The earth sciences have described a number of processes that are decidedly unpleasant for any living organisms unlucky enough to experience them, from volcanic eruptions to mass extinctions. Climatic “tipping points” are one of those scary processes. You can think of them along the lines of a kid who accidentally crests a steep hill on an old bike with no brakes—he won’t be stopping before the bottom of the hill (or he wipes out, whichever comes first). Crossing a tipping point in the climate system means being locked into some magnitude of climate change with no chance of halting it.

One scary tipping point involves the methane locked in molecular cages of ice called clathrates (or methane hydrates), found within the sediment on the seafloor. Heating up the water enough to melt hydrates and release methane adds an additional punch of greenhouse warming to whatever caused the heating. Such heating has been implicated in some ugly climate swings in Earth’s past.

Climate scientists don’t anticipate crossing this tipping point any time soon (the latest IPCC report judged it “very unlikely” this century), but that doesn’t mean hydrates aren’t the focus of research and concern. There is still much we don’t know about where hydrates are present and how much ocean warming it takes to begin destabilizing them.