Scientists have observed "dramatic and unprecedented plumes of methane" coming from the seabed of the East Siberian Arctic Shelf off the northern coast of Russia, the London Independent reported on Dec. 13. -- Dr. Igor Semiletov, the leader of a joint U.S.-Russian research cruise, said that "Earlier we found torch-like structures like this but they were only tens of meters in diameter. This is the first time that we've found continuous, powerful, and impressive seeping structures more than 1,000 meters in diameter. It's amazing." -- "Scientists estimate that there are hundreds of millions of tons of methane gas locked away beneath the Arctic permafrost," and "[o]ne of the greatest fears is that with the disappearance of the Arctic sea ice in summer, and rapidly rising temperatures across the entire Arctic region, which are already melting the Siberian permafrost, the trapped methane could be suddenly released into the atmosphere leading to rapid and severe climate change," Steve Connor said. -- Dr. Natalia Shakhova of the International Arctic Research Center at the University of Alaska Fairbanks that "The concentration of atmospheric methane [above the Arctic Ocean] increased unto three times in the past two centuries from 0.7 parts per million to 1.7ppm, and in the Arctic to 1.9ppm. That's a huge increase, between two and three times, and this has never happened in the history of the planet." -- HOWEVER, a blog entry in the New York Times rejected the implications of the Independent article and urged readers to "reach out to a couple of scientists working on this gas before you run to the ramparts" because "scientists who track methane in the atmosphere in the Arctic and elsewhere around the planet see no big surge that can be pinned on such releases." -- In particular, Andrew Revkin cited a Dec. 6, 2011, paper in the Journal of Geophysical Research according to which "the bulk of the methane stores in the east Siberian shelf are trapped roughly 200 meters below the seafloor." -- The authors of that piece concluded that "even under sustained heating, the brunt of the sub-sea methane won’t be affected in this millennium" (Revkin's paraphrase). -- In a long front-page piece published two days after Revkin's comment, the New York Times called atmospheric methane "one of the biggest looming mysteries about the future of the earth . . . one of the biggest wild cards in climate science." -- Like Revkin, Justin Gillis emphasized the uncertainties that surround the problem of melting permafrost and seemed to downplay the problem. -- Gillis had not a word to say about the kilometer-wide Siberian methane plumes discussed by the Independent....
METHANE DISCOVERY STOKES NEW GLOBAL WARMING FEARS
By Steve Connor
** Shock as retreat of Arctic releases greenhouse gas **
December 13, 2011
Dramatic and unprecedented plumes of methane -- a greenhouse gas 20 times more potent than carbon dioxide -- have been seen bubbling to the surface of the Arctic Ocean by scientists undertaking an extensive survey of the region.
The scale and volume of the methane release has astonished the head of the Russian research team who has been surveying the seabed of the East Siberian Arctic Shelf off northern Russia for nearly 20 years.
In an exclusive interview with the Independent, Igor Semiletov of the International Arctic Research Center at the University of Alaska Fairbanks, who led the 8th joint U.S.-Russia cruise of the East Siberian Arctic seas, said that he has never before witnessed the scale and force of the methane being released from beneath the Arctic seabed.
"Earlier we found torch-like structures like this but they were only tens of metres in diameter. This is the first time that we've found continuous, powerful and impressive seeping structures more than 1,000 metres in diameter. It's amazing," Dr. Semiletov said.
"I was most impressed by the sheer scale and the high density of the plumes. Over a relatively small area we found more than 100, but over a wider area there should be thousands of them," he said.
Scientists estimate that there are hundreds of millions of tons of methane gas locked away beneath the Arctic permafrost, which extends from the mainland into the seabed of the relatively shallow sea of the East Siberian Arctic Shelf.
One of the greatest fears is that with the disappearance of the Arctic sea ice in summer, and rapidly rising temperatures across the entire Arctic region, which are already melting the Siberian permafrost, the trapped methane could be suddenly released into the atmosphere leading to rapid and severe climate change.
Dr. Semiletov's team published a study in 2010 estimating that the methane emissions from this region were in the region of 8 million tons a year but the latest expedition suggests this is a significant underestimate of the true scale of the phenomenon.
In late summer, the Russian research vessel Academician Lavrentiev conducted an extensive survey of about 10,000 square miles of sea off the East Siberian coast, in cooperating with the University of Georgia Athens. Scientists deployed four highly sensitive instruments, both seismic and acoustic, to monitor the "fountains" or plumes of methane bubbles rising to the sea surface from beneath the seabed.
"In a very small area, less than 10,000 square miles, we have counted more than 100 fountains, or torch-like structures, bubbling through the water column and injected directly into the atmosphere from the seabed," Dr Semiletov said.
"We carried out checks at about 115 stationary points and discovered methane fields of a fantastic scale -- I think on a scale not seen before. Some of the plumes were a kilometer or more wide and the emissions went directly into the atmosphere -- the concentration was a hundred times higher than normal," he said.
Dr. Semiletov released his findings for the first time last week at the American Geophysical Union meeting in San Francisco. He is now preparing the study for publication in a scientific journal.
The total amount of methane stored beneath the Arctic is calculated to be greater than the overall quantity of carbon locked up in global coal reserves so there is intense interest in the stability of these deposits as the polar region warms at a faster rate than other places on earth.
Natalia Shakhova, a colleague at the International Arctic Research Center at the University of Alaska Fairbanks, said that the Arctic is becoming a major source of atmospheric methane and the concentrations of the powerful greenhouse gas have risen dramatically since pre-industrial times, largely due to agriculture.
However, with the melting of Arctic sea ice and permafrost, the huge stores of methane that have been locked away underground for many thousands of years might be released over a relatively short period of time, Dr. Shakhova said.
"I am concerned about this process, I am really concerned. But no one can tell the timescale of catastrophic releases. There is a probability of future massive releases might occur within the decadal scale, but to be more accurate about how high that probability is, we just don't know," Dr. Shakova said.
"Methane released from the Arctic shelf deposits contributes to global increase and the best evidence for that is the higher concentration of atmospheric methane above the Arctic Ocean," she said.
"The concentration of atmospheric methane increased unto three times in the past two centuries from 0.7 parts per million to 1.7ppm, and in the Arctic to 1.9ppm. That's a huge increase, between two and three times, and this has never happened in the history of the planet," she added.
Each methane molecule is about 70 times more potent in terms of trapping heat than a molecule of carbon dioxide. However, because methane it broken down more rapidly in the atmosphere than carbon dioxide, scientist calculate that methane is about 20 times more potent than carbon dioxide over a hundred-year cycle.
The Opinion Pages
METHANE TIME BOMB IN ARCTIC SEAS -- APOCALYPSE NOT
By Andrew C. Revkin
New York Times
December 14, 2011
A very important research effort has been under way during recent summers in the warming, increasingly ice-free shallows off Russia’s Siberian coast. There, an international array of scientists has been investigating widening areas of open water that are disgorging millions of tons of methane each year.
Given that methane, molecule for molecule, has at least 20 times the heat-trapping properties of carbon dioxide, it’s important to get a handle on whether these are new releases, the first foretaste of some great outburst from thawing sea-bed stores of the gas, or simply a longstanding phenomenon newly observed.
If you read the Independent of Britain, you’d certainly be thinking the worst. The newspaper has led the charge in fomenting worry over the gas emissions, with portentous, and remarkably similar, stories in 2008 and this week.
If you read geophysical journals and survey scientists tracking past and future methane emissions, you get an entirely different picture:
A paper published in Dec. 6 in the Journal of Geophysical Research appears to confirm pretty convincingly that the gas emissions seen in recent years are from a thawing process that has been under way for 8,000 years -- since seas rose sufficiently to cover the near-shore seabed. Sharp warming of the sea in the region since 1985 has clearly had an influence on the seabed, according to the paper, led by Igor Dmitrenko of the Leibniz Institute of Marine Sciences in Kiel, Germany.
But read this summary of the paper from the American Geophysical Union, which publishes the journal, and see if you feel reassured that the “methane time bomb” there is safe for a long time to come: "[T]he authors found that roughly 1 meter of the subsurface permafrost thawed in the past 25 years, adding to the 25 meters of already thawed soil. Forecasting the expected future permafrost thaw, the authors found that even under the most extreme climatic scenario tested this thawed soil growth will not exceed 10 meters by 2100 or 50 meters by the turn of the next millennium. The authors note that the bulk of the methane stores in the east Siberian shelf are trapped roughly 200 meters below the seafloor . . . [Read the rest.]
Here’s the link to the paper itself: “Recent changes in shelf hydrography in the Siberian Arctic: Potential for subsea permafrost instability.”
To review, the authors confirm “drastic bottom layer heating over the coastal zone” that they attribute to warming of the Arctic atmosphere, but conclude that “recent climate change cannot produce an immediate response in sub-sea permafrost.” That’s the understatement of the year considering their conclusion that even under sustained heating, the brunt of the sub-sea methane won’t be affected in this millennium.
It’s worth considering the risks of “single-study syndrome,” given that other recent work continues to find disturbing amounts of methane emissions in Arctic shallows.
But scientists who track methane in the atmosphere in the Arctic and elsewhere around the planet see no big surge that can be pinned on such releases. Before I distributed the link to the new paper above to relevant scientists, I’d already heard from Ed Dlugokencky, one of the top federal researchers tracking methane trends. He sent a detailed review of atmospheric measurements from the Arctic to the Equator and concluded, quite simply: "[B]ased on what we see in the atmosphere, there is no evidence of substantial increases in methane emissions from the Arctic in the past 20 years."
This all builds on what I was told in 2010, when I last visited the question of methane releases from Arctic seas. (There’s an entirely different set of questions, also with relatively reassuring answers, about the vast amounts of methane locked in permafrost on land.) I urge you to read, and pass around, the 2010 post -- “The Heat Over Bubbling Arctic Methane.”
So the next time you see a “science stunner” about Arctic methane time bombs, reach out to a couple of scientists working on this gas before you run to the ramparts.
AS PERMAFROST THAWS, SCIENTISTS STUDY THE RISKS
By Justin Gillis
New York Times
December 17, 2011 (posted Dec. 16)
FAIRBANKS, Alaska -- A bubble rose through a hole in the surface of a frozen lake. It popped, followed by another, and another, as if a pot were somehow boiling in the icy depths.
Every bursting bubble sent up a puff of methane, a powerful greenhouse gas generated beneath the lake from the decay of plant debris. These plants last saw the light of day 30,000 years ago and have been locked in a deep freeze -- until now.
“That’s a hot spot,” declared Katey M. Walter Anthony, a leading scientist in studying the escape of methane. A few minutes later, she leaned perilously over the edge of the ice, plunging a bottle into the water to grab a gas sample.
It was another small clue for scientists struggling to understand one of the biggest looming mysteries about the future of the earth.
Experts have long known that northern lands were a storehouse of frozen carbon, locked up in the form of leaves, roots, and other organic matter trapped in icy soil -- a mix that, when thawed, can produce methane and carbon dioxide, gases that trap heat and warm the planet. But they have been stunned in recent years to realize just how much organic debris is there.
A recent estimate suggests that the perennially frozen ground known as permafrost, which underlies nearly a quarter of the Northern Hemisphere, contains twice as much carbon as the entire atmosphere.
Temperatures are warming across much of that region, primarily, scientists believe, because of the rapid human release of greenhouse gases. Permafrost is warming, too. Some has already thawed, and other signs are emerging that the frozen carbon may be becoming unstable.
“It’s like broccoli in your freezer,” said Kevin Schaefer, a scientist at the National Snow and Ice Data Center in Boulder, Colo. “As long as the broccoli stays in the freezer, it’s going to be O.K. But once you take it out of the freezer and put it in the fridge, it will thaw out and eventually decay.”
If a substantial amount of the carbon should enter the atmosphere, it would intensify the planetary warming. An especially worrisome possibility is that a significant proportion will emerge not as carbon dioxide, the gas that usually forms when organic material breaks down, but as methane, produced when the breakdown occurs in lakes or wetlands. Methane is especially potent at trapping the sun’s heat, and the potential for large new methane emissions in the Arctic is one of the biggest wild cards in climate science.
Scientists have declared that understanding the problem is a major priority. The United States Department of Energy and the European Union recently committed to new projects aimed at doing so, and NASA is considering a similar plan. But researchers say the money and people devoted to the issue are still minimal compared with the risk.
For now, scientists have many more questions than answers. Preliminary computer analyses, made only recently, suggest that the Arctic and sub-Arctic regions could eventually become an annual source of carbon equal to 15 percent or so of today’s yearly emissions from human activities.
But those calculations were deliberately cautious. A recent survey drew on the expertise of 41 permafrost scientists to offer more informal projections. They estimated that if human fossil-fuel burning remained high and the planet warmed sharply, the gases from permafrost could eventually equal 35 percent of today’s annual human emissions.
The experts also said that if humanity began getting its own emissions under control soon, the greenhouse gases emerging from permafrost could be kept to a much lower level, perhaps equivalent to 10 percent of today’s human emissions.
Even at the low end, these numbers mean that the long-running international negotiations over greenhouse gases are likely to become more difficult, with less room for countries to continue burning large amounts of fossil fuels.
In the minds of most experts, the chief worry is not that the carbon in the permafrost will break down quickly -- typical estimates say that will take more than a century, perhaps several -- but that once the decomposition starts, it will be impossible to stop.
“Even if it’s 5 or 10 percent of today’s emissions, it’s exceptionally worrying, and 30 percent is humongous,” said Josep G. Canadell, a scientist in Australia who runs a global program to monitor greenhouse gases. “It will be a chronic source of emissions that will last hundreds of years.”
A troubling trend has emerged recently: Wildfires are increasing across much of the north, and early research suggests that extensive burning could lead to a more rapid thaw of permafrost.
RISE AND FALL OF PERMAFROST
Standing on a bluff the other day, overlooking an immense river valley, A. David McGuire, a scientist from the University of Alaska, Fairbanks, sketched out two million years of the region’s history. It was the peculiar geology of western North America and eastern Siberia, he said, that caused so much plant debris to get locked in an ice box there.
These areas were not covered in glaciers during the last ice age, but the climate was frigid, with powerful winds. The winds and rivers carried immense volumes of silt and dust that settled in the lowlands of Alaska and Siberia.
A thin layer of this soil thawed on top during the summers and grasses grew, capturing carbon dioxide. In the bitter winters, grass roots, leaves and even animal parts froze before they could decompose. Layer after layer of permafrost built up.
At the peak of the ice age, 20,000 years ago, the frozen ground was more extensive than today, stretching deep into parts of the lower 48 states that were not covered by ice sheets. Climate-change contrarians like to point to that history, contending that any melting of permafrost and ice sheets today is simply the tail end of the ice age.
Citing permafrost temperatures for northern Alaska -- which, though rising rapidly, remain well below freezing -- an organization called the Center for the Study of Carbon Dioxide and Global Change claimed that permafrost is in “no more danger of being wiped out any time soon than it was in the days of our great-grandparents.”
But mainstream scientists, while hoping the breakdown of permafrost will indeed be slow, reject that argument. They say the climate was reasonably stable for the past 10,000 years or so, during the period when human civilization arose. Now, as people burn immense amounts of carbon in the form of fossil fuels, the planet’s temperature is rising, and the Arctic is warming twice as fast. That, scientists say, puts the remaining permafrost deposits at risk.
For several decades, researchers have been monitoring permafrost temperatures in hundreds of boreholes across the north. The temperatures have occasionally decreased in some regions for periods as long as a decade, but the overall trend has been a relentless rise, with temperatures now increasing fastest in the most northerly areas.
Thawing has been most notable at the southern margins. Across huge areas, including much of central Alaska, permafrost is hovering just below the freezing point, and is expected to start thawing in earnest as soon as the 2020s. In northern Alaska and northern Siberia, where permafrost is at least 12 degrees Fahrenheit below freezing, experts say it should take longer.
“Even in a greenhouse-warmed world, it will still get cold and dark in the Arctic in the winter,” said Mark Serreze, director of the snow and ice data center in Boulder.
Scientists need better inventories of the ancient carbon. The best estimate so far was published in 2009 by a Canadian scientist, Charles Tarnocai, and some colleagues. They calculated that there was about 1.7 trillion tons of carbon in soils of the northern regions, about 88 percent of it locked in permafrost. That is about two and a half times the amount of carbon in the atmosphere.
Philippe Ciais, a leading French scientist, wrote at the time that he was “stunned” by the estimate, a large upward revision from previous calculations.
“If, in a warmer world, bacteria decompose organic soil matter faster, releasing carbon dioxide,” Dr. Ciais wrote, “this will set up a positive feedback loop, speeding up global warming.”
PLUMES OF METHANE
Katey Walter Anthony had been told to hunt for methane, and she could not find it.
As a young researcher at the University of Alaska, Fairbanks, she wanted to figure out how much of that gas was escaping from lakes in areas of permafrost thaw. She was doing field work in Siberia in 2000, scattering bubble traps around various lakes in the summer, but she got almost nothing.
Then, that October, the lakes froze over. Plumes of methane that had been hard to spot on a choppy lake surface in summer suddenly became more visible.
“I went out on the ice, this black ice, and it looked like the starry night sky,” Dr. Walter Anthony said. “You could see these bubble clusters everywhere. I realized -- ‘aha!’ -- this is where all the methane is.”
When organic material comes out of the deep freeze, it is consumed by bacteria. If the material is well-aerated, bacteria that breathe oxygen will perform the breakdown, and the carbon will enter the air as carbon dioxide, the primary greenhouse gas. But in areas where oxygen is limited, like the bottom of a lake or wetland, a group of bacteria called methanogens will break down the organic material, and the carbon will emerge as methane.
Scientists are worried about both gases. They believe that most of the carbon will emerge as carbon dioxide, with only a few percent of it being converted to methane. But because methane is such a potent greenhouse gas, the 41 experts in the recent survey predicted that it would trap about as much heat as the carbon dioxide would.
Dr. Walter Anthony’s seminal discovery was that methane rose from lake bottoms not as diffuse leaks, as many scientists had long assumed, but in a handful of scattered, vigorous plumes, some of them capable of putting out many quarts of gas per day. In certain lakes they accounted for most of the emerging methane, but previous research had not taken them into consideration. That meant big upward revisions were probably needed in estimates of the amount of methane lakes might emit as permafrost thawed.
Most of the lakes Dr. Walter Anthony studies were formed by a peculiar mechanism. Permafrost that is frozen hard supports the ground surface, almost the way a concrete pillar supports a building. But when thaw begins, the ground sometimes turns to mush and the entire land surface collapses into a low-lying area, known as a thermokarst. A lake or wetland can form there, with the dark surface of the water capturing the sun’s heat and causing still more permafrost to thaw nearby.
Near thermokarst locations, trees often lean crazily because their roots are disturbed by the rapid changes in the underlying landscape, creating “drunken forests.” And the thawing, as it feeds on itself, frees up more and more ancient plant debris.
One recent day, in 11-degree weather, Dr. Walter Anthony and an assistant, Amy Strohm, dragged equipment onto two frozen thermokarst lakes near Fairbanks. The fall had been unusually warm and the ice was thin, emitting thunderous cracks -- but it held. In spots, methane bubbled so vigorously it had prevented the water from freezing. Dr. Walter Anthony, six months pregnant, bent over one plume to retrieve samples.
“This is thinner ice than we like,” she said. “Don’t tell my mother-in-law! My own mother doesn’t know.”
Dr. Walter Anthony had already run chemical tests on the methane from one of the lakes, dating the carbon molecules within the gas to 30,000 years ago. She has found carbon that old emerging at numerous spots around Fairbanks, and carbon as old as 43,000 years emerging from lakes in Siberia.
“These grasses were food for mammoths during the end of the last ice age,” Dr. Walter Anthony said. “It was in the freezer for 30,000 to 40,000 years, and now the freezer door is open.”
Scientists are not sure yet whether thermokarst lakes will become more common throughout the Arctic in a warming climate, a development that could greatly accelerate permafrost thaw and methane production. But they have already started to see increases in some regions, including northernmost Alaska.
“We expect increased thermokarst activity could be a very strong effect, but we don’t really know,” said Guido Grosse, another scientist at the University of Alaska, Fairbanks. He is working with Dr. Walter Anthony on precision mapping of thermokarst lakes and methane seeps, in the hope that the team can ultimately use satellites and aerial photography to detect trends.
With this kind of work still in the early stages, researchers are worried that the changes in the region may already be outrunning their ability to understand them, or to predict what will happen.
WHEN THE TUNDRA BURNS
One day in 2007, on the plain in northern Alaska, a lightning strike set the tundra on fire.
Historically, tundra, a landscape of lichens, mosses, and delicate plants, was too damp to burn. But the climate in the area is warming and drying, and fires in both the tundra and forest regions of Alaska are increasing.
The Anaktuvuk River fire burned about 400 square miles of tundra, and work on lake sediments showed that no fire of that scale had occurred in the region in at least 5,000 years.
Scientists have calculated that the fire and its aftermath sent a huge pulse of carbon into the air -- as much as would be emitted in two years by a city the size of Miami. Scientists say the fire thawed the upper layer of permafrost and set off what they fear will be permanent shifts in the landscape.
Up to now, the Arctic has been absorbing carbon, on balance, and was once expected to keep doing so throughout this century. But recent analyses suggest that the permafrost thaw could turn the Arctic into a net source of carbon, possibly within a decade or two, and those studies did not account for fire.
“I maintain that the fastest way you’re going to lose permafrost and release permafrost carbon to the atmosphere is increasing fire frequency,” said Michelle C. Mack, a University of Florida scientist who is studying the Anaktuvuk fire. “It’s a rapid and catastrophic way you could completely change everything.”
The essential question scientists need to answer is whether the many factors they do not yet understand could speed the release of carbon from permafrost -- or, possibly, slow it more than they expect.
For instance, nutrients released from thawing permafrost could spur denser plant growth in the Arctic, and the plants would take up some carbon dioxide. Conversely, should fires like the one at Anaktuvuk River race across warming northern landscapes, immense amounts of organic material in vegetation, soils, peat deposits, and thawed permafrost could burn.
Edward A. G. Schuur, a University of Florida researcher who has done extensive field work in Alaska, is worried by the changes he already sees, including the discovery that carbon buried since before the dawn of civilization is now escaping.
“To me, it’s a spine-tingling feeling, if it’s really old carbon that hasn’t been in the air for a long time, and now it’s entering the air,” Dr. Schuur said. “That’s the fingerprint of a major disruption, and we aren’t going to be able to turn it off someday.”
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