30 Oct 2008

Melting Arctic Ocean Raises Threat of ‘Methane Time Bomb’

Scientists have long believed that thawing permafrost in Arctic soils could release huge amounts of methane, a potent greenhouse gas. Now they are watching with increasing concern as methane begins to bubble up from the bottom of the fast-melting Arctic Ocean.
By susan q. stranahan

For the past 15 years, scientists from Russia and other nations have ventured into the ice-bound and little-studied Arctic Ocean above Siberia to monitor the temperature and chemistry of the sea, including levels of methane, a potent greenhouse gas. Their scientific cruises on the shallow continental shelf occurred as sea ice in the Arctic Ocean was rapidly melting and as northern Siberia was earning the distinction — along with the North American Arctic and the western Antarctic Peninsula —of warming faster than any place on Earth.

Until 2003, concentrations of methane had remained relatively stable in the Arctic Ocean and the atmosphere north of Siberia. But then they began to rise. This summer, scientists taking part in the six-week International Siberian Shelf Study discovered numerous areas, spread over thousands of square miles, where large quantities of methane — a gas with 20-times the heat-trapping power of carbon dioxide — rose from the once-frozen seabed floor.

These “methane chimneys” sometimes contained concentrations of the gas 100 times higher than background levels and were so large that clouds of gas bubbles were detected "rising up through the water column," Orjan Gustafsson of the Department of Applied Environmental Science at Stockholm University and the co-leader of the expedition, said in an interview. There was no doubt, he said, that the methane was coming from sub-sea permafrost, indicating that the sea bottom might be melting and freeing up this potent greenhouse gas.

Gustafsson said he makes no claims that the methane release “is necessarily driven by global warming.”

Enlarge Image
International Siberian Shelf Study

International Siberian Shelf Study
Map: Siberian expedition route
But a growing body of data showing that more methane is emanating from the rapidly thawing Arctic Ocean has caught the attention of many climate scientists. Could this be the beginning, they wonder, of the release of vast quantities of sub-sea Arctic methane long trapped by a permafrost layer that is starting to thaw?

In recent years, climate scientists have been concerned about a so-called “methane time bomb” on land, which would be detonated when warming Arctic temperatures melt permafrost and cause frozen vegetation in peat bogs and other areas to decay, releasing methane and carbon dioxide. Now come fears of a methane time bomb, part two, this one bursting from the sea floor of the shallow Arctic continental shelf. The Arctic sea floor contains a rich, decayed layer of vegetation from earlier eras when the continental shelf was not underwater.

So little data is available from the Arctic Ocean that no scientists dare say with certainty whether the world is watching the fuse being lit on a marine methane time bomb. But researchers such as Natalia Shakhova —a visiting scientist at the University of Alaska in Fairbanks and a participant in some of the Siberian Shelf scientific cruises — are concerned that the undersea permafrost layer has become unstable and is leaking methane long locked in ice crystals, known as methane hydrates.

One thing is certain: the shallow Siberian Shelf alone covers more than 1.5 million square kilometers (580,000 square miles), an area larger than
Now come fears of a methane time bomb, part two, this one bursting from the sea floor of the shallow Arctic continental shelf.
France, Germany, and Spain combined. Should its permafrost layer thaw, an amount of methane equal to 12 times the current level in the atmosphere could be released, according to Shakhova. Such a release would cause “catastrophic global warming,” she recently wrote in Geophysical Research Abstracts. Among the many unanswered questions is how quickly — over years? centuries? — methane releases might occur.

Said Gustafsson, “The conventional view is that the permafrost is holding these large methane reservoirs in place. That is a view that we need to rethink and revise.”

What concerns some scientists is evidence from past geological eras that sudden releases of methane have triggered runaway cycles of climate upheaval. Martin Kennedy, a geologist at the University of California at Riverside and lead author of a paper published in Nature in June, speaks in near-doomsday terms, warning that rising methane emissions — from land and sea — threaten to radically destabilize the climate. Ice core studies in Greenland and Antarctica have shown that Earth’s climate can change abruptly, more like flipping a switch than slowly turning a dial.

“I’m very concerned that we’re near the threshold and we’re going to see the tipping point in 20 years,” Kennedy warns. Temperature increases in the Arctic of a just few degrees could unleash the huge storehouse of methane, which some have estimated would be comparable to burning all recoverable stocks of coal, oil, and natural gas.

Kennedy’s Nature article bases his warnings on a long-ago event. Sediment samples gathered in south Australia led Kennedy’s
What concerns some scientists is evidence from past geological eras that sudden releases of methane have triggered runaway cycles of climate upheaval.
team to theorize that a catastrophic era of global warming was triggered some 635 million years ago by a gradual — and then abrupt — release of methane from frozen soils, bringing an end to “Snowball Earth,” when the entire planet was encrusted in ice. He sees similarities in the mounting threats of thawing terrestrial and marine permafrost today. The question, he asks, is what will set the process in motion and when.

“Do we have a substantial risk of crossing one of these thresholds?” he asked in an interview. “I would say yes. I have absolutely no doubt that at the current rate of [greenhouse gas emissions] we can cross a tipping point, and when that occurs it’s too late to do anything about it.”

As with much climate research, the science is complex and opinions can vary dramatically. David Lawrence of the National Center for Atmospheric Research in Boulder, Colorado, is concerned, but not alarmed. Lawrence was lead author of a paper in Geophysical Research Letters, also published in June, that documented the consequences of the record loss of Arctic sea ice in 2007. Based on climate models, Lawrence and his team theorized that during periods of rapid sea-ice loss, temperatures could increase as far as 900 miles inland, accelerating the rate of terrestrial permafrost thaw. From August to October of 2007, they reported, temperatures over land in the western Arctic rose more than 4° F above the 1978-2006 average.

“If you give it [the land] a pulse of warming like that it could lead to increased degradation of permafrost,” Lawrence said in an interview. “It’s not quite a runaway situation, but it does accelerate once it starts to thaw and accumulates heat.”

Arctic soils hold nearly one-third of the world’s supply of carbon, remnants of an era when even the northern latitudes were covered with lush foliage and mammoths ranged over grassy steppes. Scientists estimate that the Siberian tundra contains as much buried organic matter as the world’s tropical rain forests.

Disappearing Arctic sea ice — summer ice extent was at its lowest level in recorded history in 2007 and almost hit that level in 2008 — also will warm the Arctic Ocean, since a dark, ice-free sea absorbs more solar radiation than a white, ice-covered one. In addition, warmer waters are pouring in from rivers in rapidly warming land regions of Alaska, Canada, and Russia, also increasing sea temperatures.

Rising ocean and air temperatures mean not only the continuing disappearance of Arctic sea ice — many scientists now think the Arctic Ocean could be ice-free in summer within two decades —
Scientists are stepping up their monitoring of the land and the sea in the Arctic.
but also mean that permafrost on the sea floor could thaw more quickly. Scientists are unsure how rapidly the subsurface permafrost is thawing, or the exact causes. One possible cause could be geothermal heat seeping through fault zones. In any case, scientists agree that Arctic sub-sea permafrost — with a temperature of 29° F to 30° F— is closer to thawing than terrestrial permafrost, whose temperature can drop as low as 9.5° F.

At this point, scientists are stepping up their monitoring of the land and the sea in the Arctic, watching to see if either time bomb — terrestrial or marine — is showing signs of going off. So far, data are scarce and monitoring networks don’t exist. “That makes it very difficult to understand and evaluate the future,” Lawrence said. Although scientists know that methane has been released in the region’s water for eons, they are unsure if the new findings represent a short-term spike or long-term trend.

Pending more research, Orjan Gustafsson shares Lawrence’s caution. When he was asked how close Earth may be to a tipping point of irreversible climate change, he replied: “Everyone would like to know the answer to that. I don’t think anyone can say.”


Susan Q. Stranahan is an award-winning journalist who has written about the environment and energy for more than three decades. She was a staff writer for the Philadelphia Inquirer from 1972 to 2000, is the author of “Susquehanna, River of Dreams,” and has written for numerous publications, including the Los Angeles Times, Washington Post, Fortune, Time, and Rolling Stone. She lives on Chebeague Island, Maine.

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Well, I guess it's a good thing the earth has been cooling sense 1998 so we don't have to worry about this "time bomb."
Posted by Robert G. on 31 Oct 2008

Robert - 1998 was the hottest year ever recorded. Since then we've had the next 7 hottest years on record - that's not exactly what you'd call "cooling".

Have a read of this link:

Posted by BG on 02 Nov 2008

All including Heather should see and read ZERO Greenhouse Emissions - The Day the Lights Went Out - Our Future World available on-line from

Because it is not a case of if.
Bob Williamson
Greenhouse Neutral Foundation
Posted by Bob Williamson on 12 Nov 2008

I find it interesting that the first comment to this
article is from a "denier". Go ahead and paint them
with a large scarlet "D".
Posted by chuck on 26 Dec 2008

The article is interesting and well stated. I find it however too qualitative, and not quantitative. What is sorely missing is good and believable numerical data such as the amount of heat energy (mega-calories) needed to melt the enormous amount of ice to make a discernable diffference in sea level. For example, it takes almost 100,000 cubic miles (miles, please note) of ice to melt for the ocean level to raise one meter (according to my calculations which I will be happy to provide). How many mega-calories does it take to bring that melting about? Where does that amount of heat energy come from? And thus, how long will it take to reach that point? It depends on the initial temperature state of the ice in question. No wonder many scientists are unsure of the urgency of the matter.
Posted by Henri Suyderhoud on 24 Jan 2009

While the Post of Henri Suyderhoud's describes a desire for more "precise" or, perhaps merely "more" numerical data concerning the subject of massive methane releases, may be admirable, he appears to be addressing the wrong concern:

If all the methane and CO2 from both subsea and land permafrost becomes gaseous and is released to the atmosphere, humans will not be worrying about how many feet of water the seas will rise in the next decade, or more.

As people will be dying by millions, far too quickly for anything but the slippage of the West Antarctic Ice Sheet(WAIS) into the Southern ocean within a few weeks, could have such an immediately deleterious effect.

As global weather systems begin to change all over the planet, some areas will lose their rain while others, ordinarily dry, will be flooded out. Fertile land will become desert, and perhaps some deserts may return to the sea, or to fertility or merely become ever larger and more dangerous.

We might well have a new equivalent of the Devonian or Permian-Triassic Extinction(s). There have been at least 5 or more major die-offs on Earth since the beginning of life here.

Why should humans be immune, especially considering the bumbling and criminally irresponsible nature of the collective abuse we have heaped upon of our plantary "space vehicle", for which there is no rescue rocket or some secret "Strangelovian" government retreat for a select few government or military officials to hide in, in perfect luxury where all will be cared for by enough young females to make for a ratio ofat least 5, prhaps 10 or even 50 women per man!
Posted by martin braun on 26 May 2009

These comments simply underscore my fundamental belief that human nature is unlikely to provide the "wisdom base" to solve the climate change problem... we are too greedy, technology and novelty driven, incompetent, and mentally limited to stop the inevitable extinction of what is now referred to as the human race. That's human nature, IMHO, written in our very genes, unlikely to change in the forseeable future, a grand lab experiment originated by a force beyond our comprehension. It's over, people, but it certainly was a rush, wasn't it?
Posted by Rich on 12 Jun 2009

are we not aware that china is adopting western consumption models? thus nearly doubling their carbon consumption? The ecosphere cannot take such a strain..not enough filtering to remove the gases produced. If we stop consumption of fossil fuels its possible we might have say ten years to completely stop and retool technology but the logistics are maddening...more then half of electricity in the states is produced by burning coal. And big oil has its claws in the american automotive industry...ironically enough though in the cash for clunkers deal..a lot of folks are trading in their SUV's for gasp smaller medium sized japanese about killing off the dinosaurs no?

There ARE models of powering motors that can be more "viable" or "green" such as the car that can run off of water. The only emission is water in a vapor. Production of electicity for our industrial and residential housing needs ....well the best thing we have is nuclear power and what to do with the the nasty tendencies of people ending up with cancer from it. The only other radiation i have seen that is close is certain power-stations having radio frequencys and certain cell phone towers.

talk about a carbon based lifeform , man. I find it highly ironic that oil is made from the rotten guts of dead "dragons". A black bile that has done us almost in in less then say a real 100 year history of consumption?
Posted by heylel shalem on 04 Sep 2009

I believe that we will come out of this global warming episode with the intent to continue a way of life which both nourishes the planet as well as nourishes our own race. The creatures of this planet have a right to life, and as such our impacts cannot be measured by the amount of money or the amount of CO2, but by the magnitude of destruction. Stop measuring GDP in Dollars and start measuring it in Greenhouse gas emissions... and you will find that per capita the countries previously thought of as third world will be the very best.

The US is a great nation, and will make it through this mess, however in the scheme of things it may be thought of as a third world country sooner rather than latter. To regain First world status we must work hard, bike, bus, and unplug from the grid. Solar Panels don't cost x dollars a killowatt they cost X less of CO2.

Posted by thomas taylor on 08 Nov 2009

Henri's question actually raises a vital point. Something we're not talking about yet is the latent heat of melting ... all the "global heating" that is melting sea ice and permafrost in the Arctic will soon enough be turned on the atmosphere.

So not only will the warmed Arctic wreck havoc with agriculture in the northern hemisphere, but we'll have a jump in global average temperature *and* the methane carbon feedback to contend with.

Pretty scary from where I'm sitting. Why aren't we urgently sucking CO2 out of the atmosphere as we move on geoengineering to refreeze the Arctic?

Posted by Julie Johnston on 26 Feb 2010



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