FAIRBANKS — Ounce for ounce, methane has an effect on global warming more
than 30 times more potent than carbon dioxide, and it’s leaking from the
Arctic Ocean at an alarming rate, according to new research by scientists
at the University of Alaska Fairbanks.
Their article, which appeared Sunday in the peer-reviewed journal Nature
Geoscience, states that the Arctic Ocean is releasing methane at a rate
more than twice what scientific models had previously anticipated.
Natalia Shakhova and Igor Semiletov at UAF’s International Arctic
Research Center have spent more than a decade researching the Arctic’s
greenhouse gas emissions, along with scientists from Russia, Europe and
the Lower 48.
Shakhova, the lead author of the most recent report, said the methane
release rate likely is even greater than their paper describes.
“We decided to be as conservative as possible,” Shakhova said. “We’re
actually talking the top of the iceberg.”
The researchers worked along the continental shelf off the northern coast
of eastern Russia — the East Siberian Arctic Shelf, which is underlain by
sub-sea permafrost.
Much like the now-submerged Beringia, the land bridge that once connected
Alaska to Russia, the East Siberian Arctic Shelf was dry land until
around 7,000 to 15,000 years ago, when it flooded and became part of the
Arctic Ocean. During that time on dry land, the shelf developed a layer
of permafrost that is now in danger of melting away and releasing vast
amounts of greenhouse gases.
Past studies in Alaska and other circumpolar regions have stated that the
boreal forests covering much of the world’s Arctic and sub-Arctic dry
land contain more than 30 percent of the world’s stored carbon. This
carbon is protected from atmospheric release in large part by the
permafrost layer.
The submerged East Siberian Arctic Shelf contains much of the same stored
carbon as the dry-land tundra just to its south, but it also contains at
least 17 teragrams of methane, the study states. A teragram is equal to 1
million tons.
Those carbon stores are similarly protected by the layer of sub-sea
permafrost, but that permafrost is teetering on the brink of
disappearing.
Core samples taken of the sub-sea permafrost by Shakhova and her peers
showed temperatures near the freezing mark, around 30 to 32 degrees. Both
the top and lower layers of sediment had already thawed.
Some climate modelers had previously suggested the sub-sea permafrost
would not thaw for 5,000 to 7,000 years, but according to Shakhova’s
team, the data gathered from the actual shelf shows the process is
happening on a much more rapid timescale.
“What we’re observing right now is much faster than what we anticipated
and much faster than what was modeled,” Shakhova said.
This revelation should be a cause for alarm, Shakhova said.
“Absolutely. We think so,” she said. “We should not only just worry. We
should study.”
Climate scientists have constructed what they call a carbon budget to
determine how much carbon-based gas, such as methane and carbon dioxide,
is being released into the atmosphere. Many climate change projections
are based on this budget.
The consensus carbon budget estimates that more than half of carbon
emissions are human-caused, but these estimates vastly underestimate the
amount of carbon stored in the Arctic shelves, Shakhova said.
“I believe strongly the Arctic sources are understated and need to be
paid more attention,” Shakhova said.
The UAF researchers also concluded the Arctic methane release creates a
positive feedback loop. As temperatures increase, more methane is
released and as more methane is released temperatures increase.
In addition, storms throughout the Arctic Ocean have increased in the
past decade, according to multiple studies cited by the UAF team. These
storms speed up the methane release just as shaking a soda causes the
carbonation to rise more rapidly to the top and escape.
In the end, the Arctic and sub-Arctic regions may have the most to lose.
“When something is warming, when warming occurs, what, do you think, part
of the globe will be affected first?” Shakhova said. “The Arctic is
warming twice as fast as the rest of the globe. ... This is what affects
the number of cyclones. This is what affects the sea ice, which is
shrinking.”
Shakhova didn’t want to dwell on predictions or possible outcomes from
such rising temperatures. What she wanted to see, she said, was more
primary research in the Arctic itself to determine what is
happening.
“Our study is not about being depressing,” Shakhova said. “It’s about
knowledge, no matter if you like it or not.”

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