New Study: Ice Sheet Retreat Led to Rapid Methane Hydrate Release at End of Last Ice Age

Andreassen et al. found evidence of large craters embedded within methane-leaking subglacial sediments in the Barents Sea, Norway. They propose that the thinning of the ice sheet at the end of recent glacial cycles decreased the pressure on pockets of hydrates buried in the seafloor, resulting in explosive blow-outs. This created the giant craters and released large quantities of methane into the water above. — Science

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At the end of the last ice age, a warming world released a portion of its carbon stores into the atmosphere. The result was, ultimately, an increase in atmospheric CO2 by around 100 parts per million and in increase in atmospheric methane by around 300 parts per billion.

This increase in greenhouse gasses was a direct response to the Earth warming by approximately 4 degrees Celsius over the course of about 10,000 years. Under a present human-forced warming that is currently 1.2 C above late 19th Century averages and that is predicted to reach between 3.3 and 7 C warming this Century if fossil fuel burning continues, it is important to consider what additional carbon forcing the Earth System will produce under such an extreme and short-term temperature departure.

A new study recently published in Science indicates that these massive craters in the sea bed off Svalbard formed as methane hydrate erupted from the sea bed when ice sheets retreated at the end of the last ice age. Many of these craters are over a kilometer wide. Image source: K. Andreassen/CAGE.

One subject of concern is the behavior of methane hydrate deposits under warming conditions. It is estimated that upward of trillions of tons of hydrate exist in various frozen deposits around the world. And that even a fractional release from these deposits could contribute to the increasing greenhouse gas overburden in our atmosphere and further exacerbate warming. A potential for such a release in the short term would add risk of increased warming this Century on top of planned emissions from human fossil fuel burning — adding urgency to already necessary rapid emissions cuts (and a related swift transition to renewable energy based economies).

Paleoclimate Evidence of Massive Hydrate Release

This past week, a new study entitled — Massive blow-out craters formed by hydrate-controlled methane expulsion from the Arctic seafloor — lends credence to concerns regarding hydrate release as a potential amplifier to human warming. The study found that as ice sheets retreated and as pressure was relieved from the sea floor near Svalbard 12,000 years ago, pockets of methane hydrate rapidly migrated toward the surface as they turned to gas. This newly gasified methane formed large, high-pressure, mounds on the sea floor. Such mounds were unstable. Sensitive to changes in the local environment, they generated explosive outbursts which released considerable volumes of methane into the ocean and ultimately also added heat-trapping carbon to the Earth’s atmosphere.

The lead author of the study, Karin Andreasson, a professor at the CAGE Centre for Arctic Gas Hydrate, Environment and Climate noted in Phys.org last week that:

As [the] climate warmed, and the ice sheet collapsed, enormous amounts of methane were abruptly released. This created massive craters that are still actively seeping methane.

Though the methane craters formed off Svalbard around 12,000 years ago as the ice sheet retreated, they are linked to deeper methane pockets and are still leaking gas into the ocean today. Image source: Andreia Plaza Faverola/CAGE.

The researchers characterized these blow-out mounds as similar to those that have recently been forming in the Russian permafrost in places like Yamal and Yakutia. And their research indicates that a process like the one that occurred off Svalbard at the end of the last ice age may be at play as permafrost thins and as gas beneath this cap of frozen soil more rapidly migrates toward the surface — creating unstable blow-out mounds. Researchers also indicated that places presently locked in surface ice — like Greenland and Antarctica — could generate further methane blow out risk as ice sheets melt, withdraw and remove pressure from the methane deposits beneath them.

Conditions in Context

These are important findings due to the fact that paleoclimate evidence of past large-scale hydrate release provides a study-identified mechanism for how permafrost hydrates and gas deposits are being liberated due to present warming, how such warming may increase their rate of liberation in the future, and how ice sheet withdrawal could contribute to this hydrate liberation trend. What remains highly uncertain is the ultimate volume of hydrate response to a given level of warming over a given period and how significantly such releases would contribute to the already very considerable heat forcing provided by human emissions. That said, the new study does add to serious concerns regarding the potential for future warming and greenhouse gas levels — which will tend to be higher than present model studies indicate due to generally not accounting for these kinds of Earth System carbon feedbacks.

Links:

Massive blow-out craters formed by hydrate-controlled methane expulsion from the Arctic seafloor

Massive Craters Formed by Methane Blow-outs on Arctic Sea Floor

Massive Craters From Methane Explosions Found in Arctic

Paleoclimate Record of Atmospheric Greenhouse Gasses

Hat tip to TodaysGuestIs

Hat tip to Andy in San Diego

New Study — Risk of Significant Methane Release From East Siberian Arctic Shelf Still Growing

Large plumes of methane bubbling up from the Arctic Ocean sea-bed, saturating the water column, venting into the air, adding significantly more heat forcing to an already dangerous, fossil fuel-based, accumulation of greenhouse gasses in the Earth’s atmosphere. It’s a nightmare scenario. One in which human-forced warming, already at 1 C above 1880s levels, is further amplified through the feedback release of ancient carbon stored over the past 8 million years of Northern Hemisphere glaciation. And a recent study by the now famous Semiletov and Shakhova team provides still more reason for appropriate concern that such an event may be in the works.

ESAS methane release organic carbon store

(Shakhova and Semiletov’s new study produces an increasingly clear picture of a destabilizing organic carbon store beneath thawing permafrost in the East Siberian Arctic Shelf region. The above images show organic carbon concentration [left frame] and rate of release of methane in grams per square meter per day over observed regions. Image source: The Royal Society.)

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By now, many of us are familiar with the controversy over the potential risks of significant-to-catastrophic methane release due to human-forced warming of the ArcticAn increasing number of observational specialists are pointing toward a risk that rapid human warming will set off the release of still more carbon in the Arctic. For some, this release is expected to be gradual. Others believe there’s enough risk of a rapid release to warrant an equally rapid emergency response.

But regardless of where you stand on the issue, new research coming to light from some of the Arctic’s top observational scientists more clearly describes what appears to be an increasingly dangerous situation.

Disintegrating Permafrost Cap in ESAS

At issue is the fact that, at the end of the last ice age, a great store of permafrost carbon was submerged as the Arctic Ocean rose. A low lying region containing about 500 billion tons of carbon as methane became inundated by the shallow sea that is the East Siberian Arctic Shelf (ESAS). The waters of this sea remained cold — below the freezing point of non-salt water in its lower reaches for most of the year. But, in some places, warmth invaded, and it is thought that small portions of the permafrost cap deteriorated.

In the near shore zones and in geologically active zones, methane conduits called taliks developed. And from these expanding taliks an increasing amount of methane bubbled to the surface.

Submerged Thermokarst Lake

(Ivashkina Lagoon was once a thermokarst lake. It has since been flooded by the Laptev Sea. For much of the time of inundation, the fresh water lake surface remained frozen. It is now thawing and releasing its organic carbon store as methane. Image source: The Royal Society.)

However, for the most part, the permafrost cap over the methane stores remained in tact — waiting to be rejuvenated by a new ice age. That is, until human industry belched billions of tons of carbon into the atmosphere, removing the possibility of a new ice age and forcing the world ocean and connecting Arctic Ocean to begin to warm in excess of peak Holocene temperatures. This warming, twice as fast in the Arctic as in the rest of the world, added still more heat pressure to the permafrost cap locking methane within the ESAS sea floor.

Now, more and more permafrost beneath the shallow ESAS waters is starting to thaw. And this, much more rapid than normal thaw is resulting in an increasing risk that methane stores beneath the permafrost cap will destabilize.

Shallow Waters, Geothermal Hot Spots, Taliks

Recent observational records by Dr. Natalia Shakhova and Dr. Igor Semiletov have found what they hypothesize to be an expanding array of methane vents in the East Siberian Arctic Shelf sea bed. According to their recent research, the vents appear to be growing more robust — bubbling up greater volumes of methane from a more vigorous and inter-connected network of channel beneath the thawing sea floor.

Atmospheric Methane September 6 2015

(Ever since 2005, atmospheric methane levels have again been on the rise. Much of this increase may be due to human emissions. However, an overburden of atmospheric methane and carbon dioxide in the Arctic zone hints that destabilizing carbon stores may also be adding substantial volumes of greenhouse gasses to the world’s airs. Image source: NOAA OSPO.)

Currently, according to Shakhova and Semiletov, methane emissions are most vigorous in the near-shore region of the ESAS and in the offshore slope region. Shakhova and Semiletov believe that near shore emissions are increasingly active due to rapid warming occurring there. Not only are the regional waters impacted by a rapidly warming Siberian land mass. They also see the flux of hotter waters from rivers issuing from the continent. As a result, the near shore region is most vulnerable to permafrost thaw and destabilization. In the slope zone, however, geological features are more active. These features provide a natural heat for the formation of taliks. And though most of this region was once frozen to the point that even geological activity did not result in methane venting, the now warming permafrost cap is generating weaker regions that natural geological heat can exploit to greater and greater degrees.

Sea Ice Melt, Storms, Heighten Methane Emissions

Ever since the mid 2000s Shakhova and Semiletov have observed what appears to be a generally heightened methane emission coming from the ESAS. Estimates for total release rates have doubled and then doubled again. By 2013, the scientists were estimating that 17 million tons of methane was venting from the ESAS sea surface each year.

The increased rate of methane release is not only due to permafrost thaw on the sea floor. It is also due to an increase in large polynyas in the ESAS during winter time as well as an overall increase in the area of open water that can be impacted by storms. An ice locked ESAS keeps more of its methane in the water column and gives the methane a longer period to be absorbed by the water or consumed by microbes. But as the ice recedes, more of the methane is able to break the surface and reach the airs above. In addition, ice free seas are more susceptible to the action of storms. Storms increase wave heights, increase the rate of breaking waves, and reduces ocean surface stratification. As a result methane moves more rapidly through the upper level water column and encounters a larger surface area from which to transfer from water to air.

An ice free ESAS is not only warmer, generating more destabilization forcing to the permafrost cap which locks in methane, it is also more and more devoid of the surface ice cap which acts as a secondary barrier to methane to air transfer.

Shakhova, Semiletov Recommend Adding ESAS Methane Release to Global Climate Models

Shakhova and Semiletov’s findings continue to compel them to issue warnings over the prospect of continuing increases in methane emissions from the ESAS and nearby seas. They conclude:

The observed range in CH4 emissions associated with different degrees of subsea permafrost disintegration implies substantial and potent emission enhancement in the ESAS as the process of subsea permafrost thawing progresses with time. While it is still unclear how quickly CH4 flux rates will change, the current process of Arctic warming and associated sea ice loss will accelerate this process. The potential for the release of substantial amounts of CH4 from the ESAS region has important implications not only for atmospheric CH4 concentrations but also, given CH4‘s potency as a greenhouse gas, for the global climate. Because the ESAS contains the largest and arguably most vulnerable stores of subsea CH4, inclusion of the ESAS source in global climate models should be considered a high priority.

Links:

The East Siberian Arctic Shelf: Further Assessment of Permafrost Related Fluxes and the Role of Sea Ice

Double the Rate of Methane Release From the Arctic Sea Floor

NOAA OSPO

Concern Over Arctic Methane Release

Threat of Permafrost Destabilization is ‘Real and Imminent’

 

Arctic Methane Alert — Ramp-Up at Numerous Reporting Stations Shows Signature of an Amplifying Feedback

Over the past few months, reporting stations around the Arctic have shown a ramping rate of atmospheric methane accumulation. The curves in the graphs are steepening, hinting at a growing release of methane from a warming Arctic environment.

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Alert, Canada Methane June 1 2015

(Alert, Canada methane graph shows atmospheric methane increases in the range of 20 parts per billion in just one year. This rate of increase is 2-3 times the global average for the past five years. A skyrocketing rate of increase. Image source: NOAA ESRL.)

A Massive Thawing Carbon Store in the Far North

The science is pretty settled. There’s a massive store of ancient carbon now thawing in the Arctic.

In the land-based permafrost alone, this store is in the range of 1.3 billion tons — or nearly double the volume in the atmosphere right now. Arctic Ocean methane hydrates in the East Siberian Arctic Shelf add another 500 billion tons. A rather vulnerable store that does not include hundreds of billions of additional tons of carbon in the deeper methane hydrates around the Arctic in places like the Gakkel Ridge, in the Deep Waters off Svalbard, or in the Nares Strait. Massive carbon stores of high global warming potential gas locked in frozen ground or in ice structure upon or beneath the sea bed.

But now human beings — through fossil fuel emissions — are dumping heat trapping gasses into the atmosphere at an unprecedented rate. These gasses are most efficient at trapping heat in the colder, darker regions of the world. And, due to a combination of massive Northern Hemisphere burning, and release from the Arctic carbon stores themselves, the highest concentrations of greenhouse gasses can be found exactly where they are needed least — in the world’s far northern zones .

Arctic Overburden May 29

(The Arctic consistently shows an overburden of methane gas — both at the ground and upper levels of the atmosphere as seen in this METOP graphic from May 29. Such an overburden is but one of many proxy indicators of a ramping rate of release.)

This accumulation and overburden of heat trapping gasses is causing the Arctic to rapidly warm. A rate of warming (now at half a degree Celsius per decade for most regions) that is providing a heat forcing pushing the ancient carbon stores to release. A heat forcing now greater than at any time in the past 150,000 years (and likely more due to the fact that the Eemian Arctic was rather cool overall). A heat forcing rapidly ramping toward at least a range not seen since major glaciation began in the Northern Hemisphere 2-3 million years ago.

The problem for science, then, is two-fold. First, as oceans warm and permafrost thaws, how rapidly will the carbon stores release? And, second, how much of that carbon store will release as CO2, and how much will release as methane? From the point of view of global warming, both CO2 and Methane emissions feedback is a bad outcome of human-forced warming. But methane, which has a global warming potential of between 25 and 120 times CO2 over human-relevant timescales, has a real potential to make an already bad human heating of the Earth System much, much worse.

Methane Bubbles in Thermokarst Lake

(Image source via Science 2.0.)

Most Arctic Reporting Stations Show Rapid Ramping of Methane Gas Accumulation

For this reason, monitoring methane gas accumulation in the Arctic is a key feature of global climate change risk analysis. If the Arctic shows a spiking rate of methane accumulation, then the carbon stores are more susceptible to rapid release of potent heat trapping gasses and we are facing a high urgency situation in need of rapid global response.

Over the past decade, the Arctic has shown numerous isolated or regional spikes to very high methane levels with an overall continued accumulation within the atmosphere. The Arctic also displayed a major overburden of both methane and CO2 — proxy indications of local carbon store feedbacks already ongoing on a minor-to-moderate scale. This combination of overburden and spikes provided a troubling context, especially when adding in observations of methane store release through thermokarst lakes and, later, blow-holes in locations like Yamal, Russia. But up until last year, we had not seen a third, and more troubling, indicator — the ramping rates of atmospheric methane accumulation that would be an early warning that the Arctic carbon store was indeed starting to blow its stack.

But now, that signal is starting to show up at almost every Arctic reporting station. A steepening curve in the Arctic atmospheric methane graphs. A signal we really, really don’t want to be bearing witness to:

Barrow Methane June 1 2015Alert, Canada Methane June 1 2015

Summit Greenland Methane June 1 2015Svalbard Methane June 1 2015

(Major reporting stations from Svalbard to Barrow show a ramping atmospheric methane accumulation [Click on individual images to expand]. It’s a signal that is yet one more indicator of an amplifying methane and greenhouse gas feedback to human warming now going on in the Arctic. Images provided by NOAA ESRL.)

Now, it seems, at the very least, we are witnessing a spike in Arctic atmospheric methane accumulation. Let’s hope it’s just a spike and not the start of another ugly exponential curve associated with human-forced atmospheric warming. But if we are witnessing the early ramp of such a curve, we should be clear that we are now in the context of a worst-case climate change scenario.

Hot-Button Topic of Critical Importance

For years, conjecture over the possible rate of Arctic Methane release in a human-warmed Arctic has been the source of extreme scientific and media-based controversy. Major oil companies have used the issue as an excuse to continue fossil fuel burning (irresponsibly spreading the meme — ‘we’re screwed, so we may as well just keep burning anyway’). Major climate scientists and related media outlets have sought to tamp down concern over large-scale methane release by issuing articles with titles like ‘Apocalypse Not’ with many generally insisting that there is practically zero likelihood of a large-scale methane release or major amplifying feedback. Meanwhile, the observational studies have continued to indicate risk of at least moderate and possibly strong methane feedback in an age of rapid human heating of the Arctic environment (studies like this recent paper which observed microbes tripling the rate of methane gas release in thermokarst lakes as a response to Arctic temperature increase.) Finally, a group of very concerned observational scientists like Natalia Shakhova, Igor Simeletov and Peter Wadhams have warned that a large-scale methane release is likely imminent and begs a major response from the global community (sadly, many of these proposed responses have come in the form of geo-engineering — methods which are far less likely to succeed and far more likely to generate unforeseen and highly disruptive consequences than simple cessation of human fossil fuel emission and a transition to carbon-negative civilizations).

Mauna Loa Methane June 1 2015

(Mauna Loa methane measure through June 1, 2015 shows that lower Latitude regions are also starting to follow a ramping rate of increase. Image source: NOAA ESRL.)

All this controversy aside, what we observe now is the following:

  1. Arctic methane and CO2 overburden — proxy indication of environmental release.
  2. Increasing rates of release, indications of increasing release, or possibly increasing release from single sources such as thermokarst lakes, peat bogs, wildfires, and sea bed hydrates and submerged tundra.
  3. A multiplication of observed or discovered methane release sources — thermokarst lakes, methane blow holes, wildfires etc.
  4. A ramping rate of atmospheric methane accumulation at reporting stations throughout the Arctic (most but not all stations).
  5. A ramping rate of atmospheric methane accumulation from global proxy monitors like Mauna Loa and in the global atmospheric average.

Together, these observations represent a troubling trend that, should it continue, will be proceeding along or near a worst-case climate sensitivity track. As such, these new ramping rates of increase in Arctic atmospheric monitors are a very unfortunate indicator.

Links:

NOAA ESRL

NOAA OSPO

Arctic Methane Skyrocketing

Microbes in Thermokarst Lakes Increase Methane Generation with Warming

Arctic Sea Ice Melt, Methane Release Shows Amplifying Feedback to Human-Caused Climate Change

 

Methane Monster’s Grumbling Goes Global: 570 Methane Plumes Discovered on Atlantic Ocean Sea Floor

Greenhouse gas concentrations spike — heating the atmosphere and the deep ocean after a period of glaciation during which vast stores of carbon accumulated. Massive volumes of this carbon lay dormant — trapped in frozen ground and in clathrates on the sea bed. As the ocean and airs warm, these carbon stores release causing a massive spike of additional greenhouse gasses to hit the atmosphere and setting off ever-more-rampant heating. The cycle continues until much of these carbon stores out-gas, pushing the Earth into a hothouse state.

Sound chillingly familiar?

What I’ve just described is the process that most scientists believe occurred during the worst mass extinction event in the geological past — the Permian Extinction. A hothouse event that killed 95% of life in the oceans and 70% of life on land. And what humans are now doing to the Earth’s airs and waters through CO2 and related greenhouse gas emissions may well be shockingly similar.

Large methane release over East Siberian Sea August 2014

(Substantial methane release from the East Siberian Sea surface during early August likely in the range of 0.5 to 1 megatons points toward both atmospheric methane overburden and likely carbon store instability and large scale out-gassing in the Arctic. Image credit: Sam Carana and NOAA.)

From the Arctic tundra to the Arctic Ocean sea bed to the Atlantic Ocean, we have growing evidence of methane and CO2 releases from carbon stores that may well be at the start of just such a large scale feedback. Time and time again, we see evidence of significant (but not yet catastrophic) emissions from Arctic methane stores (see image above). With each passing year, the methane overburden in the Arctic air grows. And we have had increasing evidence of a growing volume of releases from the East Siberian Arctic Shelf sea bed, to the methane emitting melt lakes proliferating over the thawing permafrost, to the chilling and terrifying methane blow holes discovered this year in Siberia.

As of 2011, many Arctic scientists believed that human-caused heating could set off methane and CO2 emissions from that region equivalent to between 10 and 35 percent or more of current human fossil fuel burning by the end of this century. The lower boundary of this range is with rapid reductions in human greenhouse gas emissions, the upper boundary is under business as usual. Such a 35 percent equivalent emission, happening year on year for centuries, would be more than enough to push Earth into a runaway hothouse scenario without any further human greenhouse gas releases. And it is this scenario, or the even more chilling worse case of very rapidly ramping Arctic methane outbursts, that we should be very concerned about.

Atlantic Methane Hydrate Destabilization off US East Coast

Unfortunately, the vast carbon store in the Arctic is not the only potential source of heating feedback carbon release. For around the world, upon and beneath the ocean sea bed, billions of tons of methane lay stored in clathrate structures. These stores are separate from the large carbon deposits in the Arctic. But they are no less dangerous.

In 2012, Nature issued a study that found a store of clathrates composing billions of tons of methane was now destabilizing off the US East Coast. The study predicted large-scale releases in the multi-gigaton range from the southern region of the East Coast methane clathrate store due both to changes in the Gulf Stream circulation and to warming bottom waters — both impacts set off by human-caused climate change. The study was uncertain how fast such a release could occur, but noted that the eventual release was likely due to wide-scale clathrate degradation associated with ocean bottom warming.

Methane Seep off US East Coast

(Methane Seep off US East Coast. Image source: Nature.)

This year, research vessels returned to the region and found 570 plumes of methane venting from destabilized clathrate stores there. This result was surprising due to the fact that only three methane seep sources had previously been identified. The plumes were discovered in 50 to 1,500 meters of water, with most of the seeps occurring at between 250 and 600 meters depth, along a zone stretching from Cape Hatteras to Georges Bank. The seeps ranged in age from recent to 100 or even 1000 or more years old. Overall, the prevalence of seeps was more widespread than expected.

“This is the first time anyone has systematically mapped an entire margin,” Christian Berndt, a marine geophysicist at GEOMAR in Kiel, Germany, who was not involved in the study, said in an interview to Science Magazine. “They found that there was much more methane coming out than was suspected beforehand.”

Currently, only a small amount of the methane being released from the sea bed off the US East Coast is likely hitting the atmosphere and is probably not contributing anywhere near the volume of known emission sources from the East Siberian Arctic Shelf. Most of the gas is just absorbed by the water column, increasing acidification in the region and contributing to anoxia. But the known clathrate store off the US East Coast is very significant and large scale releases could result in much more widespread anoxia, acidification, and provide a substantial atmospheric heating feedback to human-caused warming. Very large and catastrophic outbursts could also result in slope collapse and generate tsunamis along the US East Coast. A concern that researchers may also need to further investigate.

Overall, as much as 300 to 400 gigatons of methane could be at risk and even a fraction of this store hitting the atmosphere would cause serious and lasting harm.

Overall, it is estimated that at least 30,000 methane seeps like the ones recently discovered off the US East Coast may now be active with potentially 10,000 in the East Coast region now under investigation. The current study provides a good base line for further exploration of what may well be a rather significant problem going forward.

“It highlights a really key area where we can test some of the more radical hypotheses about climate change,” said John Kessler, a professor at the University of Rochester, in an interview with the New York Times. “How will those release rates accelerate as bottom temperature warms?”

The acceleration would indeed have to be substantial to add to the already significant and troubling Arctic methane and CO2 release. But the sea bed stores are vast and the rate of human warming is very rapid. So the global ocean clathrate store is something to keep under close watch and the discovery of yet one more source that is already emitting at faster than expected rates is not at all comforting.

Links:

Widespread Methane Leakage From Sea Floor on Northern US Atlantic Margin

From Glaciation to Hothouse — Why the Permian Extinction is Pertinent to Human Warming

Recent Changes to the Gulf Stream Causing Widespread Hydrate Gas Destabilization

New Study Shows East Coast Hydrates Destabilizing

High Risk of Permafrost Thaw

Sam Carana

NOAA

Scientists Discover Hundreds of Methane Leaks Bubbling Up From the Atlantic Sea Floor

Sea Level Rise Found to Cause Slope Collapse, Tsunamis, Methane Release

Large Methane Plumes Discovered on Laptev Continental Slope Boundary: Evidence of Possible Methane Hydrate Release

080407-O-xxxxX-004

(The Swedish Icebreaker Oden — now home to the 80 scientists and tons of equipment of the SWERUS 2014 research expedition aimed at measuring sea floor methane release throughout the Arctic this summer. Among the scientists leading the expedition is Igor Semiletov whose 2011 expedition discovered 1 kilometer wide plumes of methane issuing from the floor of the East Siberian Arctic Shelf. Image source: Commons.)

SWERUS-C3 researchers have on earlier expeditions documented extensive venting of methane from the subsea system to the atmosphere over the East Siberian Arctic Shelf. On this Oden expedition we have gathered a strong team to assess these methane releases in greater detail than ever before to substantially improve our collective understanding of the methane sources and the functioning of the system. This is information that is crucial if we are to be able to provide scientific estimations of how these methane releases may develop in the future (emphasis added). — Örjan Gustafsson

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Over the past few years, the Arctic has been experiencing an invasion.

Emerging from the Gulf Stream, a pulse of warmer than normal water propagated north past Iceland and into the Barents Sea. There, it dove beneath the surface fresh water and retreating sea ice, plunging to a depth of around 200-500 meters where it concentrated, lending heat to the entire water column. Taking a right hand turn along the Siberian Continental Shelf, it crossed through the mid water zones of the Kara. Finally, it entered the Laptev and there it abutted against the downward facing slopes of the submarine continental region.

As the water temperatures at these depths warmed, researchers began to wonder if they would trigger the destabilization of methane hydrate stores locked  in deeper waters along the shelf boundary. And, now, a new expedition may have uncovered evidence that just such an event is ongoing.

Methane Hydrates and Troubling Releases from the East Siberian Arctic Shelf

Oceanic methane hydrates form when methane upon or beneath the sea bed freeze into a crystalline ice lattice. It is a hybrid water-methane mixture that only remains stable at higher sub-sea pressures and lower temperatures. Normally, oceanic hydrates form at great depth (about 600 meters or deeper) where a combination of high pressure and low temperature are the prevailing environmental factor. But the colder Arctic is a sometimes exception to this general rule.

In recent years, deep ocean warming due to human caused climate change has accelerated. It is feared that this warming may unlock vast stores of methane laying frozen along the deep sea bed or in more vulnerable continental shelf slope zones.

This warming is also feared to have begun a process of methane release along a unique submarine feature called the East Siberian Arctic Shelf (ESAS). There rising temperatures are hypothesized to have sped the thaw of submarine permafrost.

Frozen permafrost stores biologically generate gaseous methane at depths of 10-80 meters. Methane hydrate stores are locked away at depths starting at around 100 meters. Submerged beneath only a couple hundred feet of water, these methane stores are much shallower and, therefore, are in a naturally unstable zone.

The East Siberian Sea zone is unique due to the fact that it was only recently flooded, in geological terms. The frozen permafrost has only rested beneath the Arctic Ocean waters since the end of the last ice age and much of it remained frozen due to chill Arctic conditions. But now, human-caused climate change is driving warmer and warmer waters into the Arctic environment.

Elevated Methane ESAS

(Elevated atmospheric methane levels over East Siberian and Laptev Seas during October of 2013. Image source: Arctic News via Methane Tracker)

As the warming progressed during the first decade of the 21st Century, researchers observed what appeared to be an increasing release of methane from these thawing permafrost stores. In 2011, plumes from the sea bed stretching 1 kilometer across were observed by an Arctic expedition headed by Igor Similetov and Natalia Shakova. It appeared that the 250 to 500 gigatons of carbon locked in the ice in that shallow ocean was destabilizing and releasing from the sea floor as methane.

Now it is estimated that about 17 megatons of methane from this store vents through the shallow waters into the atmosphere each year. But this may just be the start of a far larger emission.

Methane Hydrate Release During Past Hothouse Events

Though the ESAS carbon and methane store is arguably one of the most vulnerable to human-caused warming, a far greater store of methane hydrate is estimated to be locked in crystalline ice lattice structures along the world’s continental slope systems and in the world’s deep ocean environments. Since the Earth has been cooling for the better part of 55 million years, a huge store of carbon as methane is now thought to have accumulated there. In total, between 3,000 and 10,000 gigatons of carbon are estimated to be captured in this vast store.

methane bubbles near the Laptev sea surface

(Methane bubbles near the Laptev Sea surface as observed by the SWERUS expedition last week. These bubbles were issuing from what are thought to be destabilizing methane hydrates along the Outer Laptev Continental Slope zone. Image source: Stockholm University.)

Global warming science, especially the science related to paleoclimate, indicates that Earth Systems warming tends to dump a lot of heat into the deep ocean. The atmosphere ocean-interface along the equator warms and becomes salty due to enhanced evaporation. The warmer, saltier water sinks, driving heat into the deep ocean. At the poles, ice sheet melt sends out a wave of fresh water along the ocean surface. The fresh water acts as an insulator between atmosphere and water, locking the warm water beneath the surface and pushing it toward the bottom. This process, called ocean stratification, is, among other things, an ocean heat exchange machine that turns the ocean bottom into a warming-induced house of horrors.

We would expect a similar process to be set in motion through human warming.

Ultimately, this combination of forces results in a collision of warm water with frozen methane stores and serves as a mechanism for their destabilization. If even a portion of this deep ocean methane hits the air, it can further accelerate already rampant warming.

Today, we may be at the start of just this kind of process.

Large Methane Plumes Discovered Along The Laptev Slope Boundary

Last week, large plumes of methane were found to be issuing from the outer Laptev Sea floor at the border zone where the bottom climbs up to meet the East Siberian Arctic Shelf. Researchers on the scientific study vessel Oden found:

elevated methane levels, about ten times higher than in background seawater, [that] were documented … as we climbed up the steep continental slope at stations in 500 and 250 m depth.

Expedition researchers noted:

This was somewhat of a surprise. While there has been much speculation of the vulnerability of regular marine hydrates (frozen methane formed due to high p [pressure] and low T [temperature]) along the Arctic rim, very few actual observations of methane releases due to collapsing Arctic upper slope marine hydrates have been made.

An Ice-Free Laptev Sea

(An ice-free Laptev Sea on July 28, 2014. Last week, researchers discovered a kilometers wide plume of methane bubbling up from the Continental Shelf sea bed in these typically-frozen waters. Image source: LANCE-MODIS.)

Overall the size of the release zone was quite large, covering several kilometers of sea bed and including over 100 methane seepage sites:

Using the mid-water sonar, we mapped out an area of several kilometers where bubbles were filling the water column from depths of 200 to 500 m. During the preceding 48 h we have performed station work in two areas on the shallow shelf with depths of 60-70m where we discovered over 100 new methane seep sites.

Due to the depth and location of the methane above the continental slope zone, researchers hypothesize that the source of the methane is from hydrate stores in the region.

It is worth noting that though it is rare to observe methane releases from the upper slope zone, current science has found destabilizing hydrates in deep water off the US East Coast along the continental shelf slope zone and in deep waters off Svalbard among other places. In addition, satellite observation of the Arctic Ocean has recently shown periods of high and above normal methane readings in the Laptev, Kara and East Siberian Seas. Elevated atmospheric readings have also appeared over the Nares Strait near Greenland. These are all zones that have experienced substantial deep ocean warming over the past few decades.

SWERUS 2014 is now heading toward ESAS waters where so many large methane plumes were discovered in 2011. There, the expedition hopes to use its impressive array of sensors and expertise to better define and understand what appear to be large-scale but not yet catastrophic methane releases underway there.

Links:

SWERUS 2014

SWERUS-C3

LANCE-MODIS

Stockholm University

Arctic Methane Monster Shortens Tail

Arctic News

Commons

Hat tip to TodaysGuestIs

Hat tip to Colorado Bob

 

 

 

 

 

 

 

 

The Arctic Methane Monster Stirs: NASA’s CARVE Finds Plumes as Large as 150 Kilometers Across Amidst Year of Troubling Spikes

Barrow Methane

(Barrow Methane Record 2009 to Present. Image source: NOAA)

In late June and early July, Barrow Alaska showed two methane readings in excess of 1975 parts per billion. Sadly, this most recent methane spike is likely not to be an outlier.

The Barrow spike came in conjunction with a number of other anomalously high methane readings in the Arctic region during 2013. Most notably, the Kara, Barents and Norwegian Seas all showed atmospheric methane levels spiking to as high as 1935 parts per billion during the first half of 2013.

Kara, Barent, Norwegian Methane

(Kara, Barents, Norwegian Methane. Image source: Dr. Yurganov)

Averages in this and other regions around the Arctic are at new record highs even as atmospheric methane levels continue inexorably upward. For reference, Mauna Loa shows average global atmospheric methane levels are now at around 1830 parts per billion. These levels were around 700 parts per billion at the start of the industrial revolution before they rocketed upward, roughly alongside increasing CO2 concentrations, as fossil fuel based industry saw its dramatic expansion over the past couple of centuries.

Now, human global warming is beginning to unlock a monstrous store of methane in the Arctic. A source that, in the worst case, could be many times the volume of the initial human emission. To this point, areas around the Arctic are now showing local methane levels above 1950 parts per billion with an ever-increasing frequency. The issue is of great concern to scientists, a number of which from NASA are now involved in an investigative study to unearth how large and damaging this methane beast is likely to become.  (You can keep account of these methane spike regions in real time using the Methane Tracker Google app linked here. )

CARVE Finds 150 Mile Wide Methane Plumes

A NASA program is now surveying Arctic methane releases to determine their level of amplifying feedback to human caused warming. Understanding the Arctic’s response to human warming is very important because vast stores of carbon many times the volume of human emissions over the past 200 years lay locked in both permafrost and in methane hydrates throughout the Arctic. As humans have caused the Earth to warm, sea ice and tundra melt have allowed organic carbon to decompose and bubble up in the form of methane and CO2 with ever greater force. Since a significant fraction of these Arctic carbon releases are in the form of methane, and because methane provides as much as 100 times the warming effect of CO2 by volume, even a small proportionate release of this vast carbon store could provide an extraordinarily powerful amplifying feedback to human caused climate change.

Recent studies have found that only a 1.5 degree Celsius global temperature increase puts these stores in jeopardy of large release. The amount of warming since the start of the Industrial Revolution is already at least .8 degrees Celsius (about 1/6th the difference between now and the last ice age, but on the side of hot). Perhaps more importantly, temperature forcing by human greenhouse gas emissions have done proportionately more work to melt ice and warm oceans than previously expected. As a result, the ice which locks in these vast carbon stores is disappearing at a rate far greater than most global models anticipated. This more rapid pace of thaw causes Earth Systems feedbacks to human warming to be an increasingly dire issue now.

As a result, we already have numerous instances of increased methane release around the Arctic. In 2011, a Russian expedition to the East Siberian Arctic shelf found vast plumes of methane 1 kilometer across rising up from the sea bed. All across the Arctic, researchers are finding methane bubbling up from tundra melt ponds. The concentrations of some of these melt ponds are so high that, in some cases, they burst into plumes of flame when lit.

Methane released from melt lake, Arctic

(Methane release from Arctic Melt ponds in high enough concentration to burn when lit. Image source: Sustainable Development Blog)

These methane sources also provide a serious fire hazard to the fragile Arctic environment, serving as fuel to massive tundra fires. Such fuel sources likely worsened a number of Arctic fires including this year’s Quebec inferno in which a single fire consumed 1,600,000 acres and sent plumes of smoke all the way across the Atlantic to Europe or last year’s Siberian fires that consumed millions of acres and whose smokes crossed the Pacific to fill valleys in Canada. The soot from these fires is yet one more amplifying feedback to climate change, as evidenced in a recent Los Alamos Laboratories study. Arctic fires, of late, have packed a punch far more powerful than even their southern brethren who’ve caused so much damage and loss to communities in recent years. The explosive nature of these tundra fires is plainly visible in this image of a massive Alaska blaze, larger than Rhode Island, provided below:

Massive tundra fires Alaska

(Image source: New Scientist)

Now, CARVE is finding its own evidence of massive Arctic methane emissions. Charles Miller, NASA’s principle investigator for the CARVE project, in a recent article, noted that the mission had discovered numerous atmospheric methane plumes in the Arctic. Some of these atmospheric plumes were of immense and troubling size, stretching as wide as 150 miles across.

Miller also notes:

“As temperatures warm, it’s thought that … organic materials could decompose more rapidly and give rise to gases such as carbon dioxide and methane,” Miller said. “The anticipated release of carbon should accelerate climate change…I think the experts all agree that that’s the case. The question that we’re grappling with is how much carbon might be vulnerable to release, and how fast might it be released.”

The CARVE mission is still in progress and end results are pending. But these initial reports from Miller and his team add to the disturbing evidence already arising from the Arctic. Evidence that became widely apparent in 2012 as Arctic methane release emerged as a powerful amplifying feedback to human-caused warming. In short, it appears that the Arctic methane response to human warming began sometime late last century and ramped up throughout the 2000s. Now, the Arctic appears to be providing an increasingly powerful amplifying feedback to human caused warming. It is a dangerous situation and one that should be abated as swiftly as possible through a prompt series of ongoing actions.

To these points, the following video, provided by NBC News gives excellent context.

As I’m unable to embed, the link to this video is provided here.

 

I would, however, like to add one caveat:

Global warming is not likely to unfold in a manner similar to the events depicted in the sci-fi movie “The Day After Tomorrow.” The pace of damage will be slower at first with weather worsening over time, sea level rise gradually worsening, and impacts to crops and agriculture increasing year by year, decade by decade. In this long ramping up period, there are increasing risks of single catastrophic events. But such events won’t have a neat finish. They will happen again and again, with risks and effects worsening as atmospheric heat energy increases. Perhaps, most importantly, humans will have to recover from these events in base conditions that are already difficult to manage.

As such, human climate change represents a long emergency of increasingly worsening base conditions even as the risk of increasingly damaging catastrophic events continues to rise over time. It is this ratcheting effect of climate change that makes it so deadly. The increasingly difficult base conditions make maintenance of human civilization far more difficult even as it reduces the chance that human systems will effectively recover from a number of devastating catastrophes that are surely in the pipe.

Once the climate juggernaut gets rolling it unleashes and multiplies a number of terribly monstrous and ever-worsening events. And it is for this critical reason that we need to get a handle on our carbon emissions as rapidly as possible.

Links:

NOAA

NASA’s CARVE Mission

Methane Tracker

Methane Forum Posts: Arctic Ice Blog

Vast Reservoirs of Arctic Carbon Could Effect Global Warming

A4R Methane Tracking

Sustainable Development Blog

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