Swedish study finds “vast methane plumes” coming from the ocean floor, which could accelerate global warming
By Megan Darby
When researchers from Stockholm University found plumes of methane rising from the seabed, the chief scientist’s response was mild.
“This was somewhat of a surprise,” Örjan Gustafsson wrote in his blog.
When glaciologist and blogger Jason Box saw their findings, he put it rather more strongly: “That’s damn scary.”
If even a small fraction of Arctic sea floor carbon is released to the atmosphere, we’re f’d.
— Jason Box (@climate_ice) July 29, 2014
The subject of Box’s concern was methane released from the ocean. Methane is a potent greenhouse gas, with around 20 times the warming effect of carbon dioxide.
What is more, the scientists suspect climate change could make such methane releases more likely, in a feedback loop.
Box, who has been studying the Greenland ice sheet’s sensitivity to weather and climate for 20 years, was already losing sleep about occasional spikes in methane levels in the area. He called these outlying results “dragon’s breath”.
While there was growing evidence of high methane levels over the Arctic Ocean, this Swedish study was the first to record methane bubbles rising to the surface.
Gustafsson and his team were exploring the Laptev Sea, on the edge of the Arctic.
From icebreaker ship Oden, they used sonar and chemical analysis to measure methane in the water.
They found plumes of the gas rising from depths of between 150m and 500m. Levels of dissolved methane in the water were between 10 and 50 times background levels.
Gustafsson said the gas may be released from methane hydrates collapsing on the sea bed.
“While there has been much speculation about the vulnerability of regular marine hydrates along the continental slopes of the Arctic rim, very few actual observations of methane releases due to collapsing marine hydrates on the Arctic slope have been made,” he blogged.
A “tongue” of warmer water from the Atlantic could be behind the breakdown of methane hydrates. There is some evidence that part of the ocean is getting warmer.
Box said the findings showed the importance of reducing man-made carbon emissions.
“Fossil fuel burning is the trigger mechanism poking the climate dragon,” he wrote. “The cautionary principle makes clear we have to keep this dragon in the ground.”