How the ocean鈥檚 frozen methane is being unlocked by climate change
Scientists from the University of Washington have spotted bubble plumes off the Washington and Oregon coast, suggesting that frozen methane deep in the ocean is thawing.
More importantly, this conversion means it is transforming a 鈥渄ormant solid to a powerful greenhouse gas,鈥� UW's Hannah Hickey writes聽.
What this might mean for climate change is uncertain, the researchers emphasized, though they said local marine life and fisheries will be affected.
Methane is an extremely potent greenhouse gas, with a pound-for-pound impact that is than carbon dioxide over a 100-year period.
Ironically, what appears to be driving the transition is climate change itself. The activity was detected about a third of a mile below the ocean鈥檚 surface, which experiences warmer temperatures, researchers said.
The team examined 168 methane plumes over the past decade, concluding that subsurface warming is the cause of the methane鈥檚 release. The researchers鈥� findings are to be published in the journal聽,聽a journal of the American Geophysical Union.
鈥淲hat we鈥檙e seeing is possible confirmation of what we predicted from the water temperatures: Methane hydrate appears to be decomposing and releasing a lot of gas,鈥� H. Paul Johnson, the UW professor of oceanography who led the study, told Ms. Hickey. 鈥淚f you look systematically, the location on the margin where you鈥檙e getting the largest number of methane plumes per square meter, it is right at that critical depth of 500 meters.鈥�
鈥淲e see an unusually high number of bubble plumes at the depth where methane hydrate would decompose if seawater has warmed,鈥� said Professor Johnson. 鈥淪o it is not likely to be just emitted from the sediments; this appears to be coming from the decomposition of methane that has been frozen for thousands of years.鈥�
