The Mechanism

What is the mechanism behind accelerated warming of the Arctic Ocean, huge abrupt methane eruptions from the seafloor of the Arctic Ocean and skyrocketing temperatures?

1. Potential for Methane Release in Arctic

Vast amounts of methane are stored in hydrates under the seafloor of the Arctic Ocean. Furthermore, vast amounts of methane in the form of free gas are contained in sediments under the seafloor of the Arctic Ocean. Thirdly, vast amounts of carbon are frozen in the permafrost and much may enter the atmosphere in the form of methane as the permafrost continues to thaw.

Natalia Shakhova et al. in 2010 estimated the accumulated potential for the East Siberian Arctic Shelf (ESAS) region alone (image on the right) as follows:
- organic carbon in permafrost of about 500 Gt
- about 1000 Gt in hydrate deposits
- about 700 Gt in free gas beneath the gas hydrate stability zone.

In early 2014, Sam Carana estimated annual methane emissions from hydrates and permafrost at 100 Tg (i.e. 0.1 Gt). This methane will contribute to further warming of the air over the Arctic and the North Atlantic, causing further extreme weather events, such as heatwaves and storms along the path of the Gulf Stream from the North Atlantic into the Arctic Ocean, in turn triggering further releases from hydrates at the seafloor of the Arctic Ocean and threatening to escalate into runaway global warming.

Such methane eruptions are caused by warming water of the Arctic Ocean, which in turn is due to emissions by people. Some elements of the mechanism causing methane to erupt from the seafloor are described in more detail below.

2. Ocean Heat

From: Ocean Temperature Rise continues

Above graph, based on NOAA data, shows a polynomial trendline pointing at an October Northern Hemisphere sea surface temperature anomaly rise of more than 5°C (9°F) by 2050, compared to the 20th century average, from an earlier post.

Waters at greater depth are also warming rapidly, as illustrated by the image on the right, from an earlier post, showing a rise in ocean heat up to 2000 m deep that has more than doubled over the past decade. Data from 2005 through to 2014 contain a polynomial trendline that points at a similar rise by 2017, followed by an even steeper rise.

The North Atlantic is warming rapidly, with sea surface temperature anomalies as high as a 12°C (21.6°F) recorded east of North America earlier this year, as illustrated by the image below.

A warmer North Atlantic is a major contributor to the rapidly warming waters of the Arctic Ocean, since the Gulf Stream keeps carrying warmer water into the Arctic Ocean all year long.

A further contributor is a warmer North Pacific.

Further contributions come from the combined impact of numerous feedbacks, in particular changing winds and currents, cryosphere changes and methane releases, as further described below.

From: Watch where the wind blows

3. Feedbacks: Changing Winds and Currents, Cryosphere Changes and Methane

- Changed Winds and Currents

Emissions by people are not only causing temperatures of the atmosphere and oceans to rise, they are also causing winds and ocean currents to change. Such changes can in turn result in heatwaves that are more intense and that persist for prolonged periods. Furthermore, strong northbound winds, combined with strong precipitation and waves can speed up the volume of warm water carried by Gulf Stream into the Arctic Ocean, as discussed in an earlier post. 

- Arctic Sea Ice

A warming atmosphere, warming oceans and decline of the Arctic snow and ice cover all go hand in hand. The IPCC concluded in AR5 that, for RCP8.5, the Arctic Ocean will likely be nearly ice-free in September before mid-century. Prof. Peter Wadhams warned, back in 2012, that the Arctic Ocean could be virtually ice-free within a few years. An exponential trendline based on sea ice volume observations shows that sea ice looks set to disappear in 2019, while disappearance in 2015 is within the margins of a 5% confidence interval, reflecting natural variability, as discussed at the FAQ page.

- Permafrost

Permafrost decline will cause Arctic temperatures to rise, due to albedo change and due to carbon that is contained in the permafrost and that can be expected to be released in the form of methane or carbon dioxide as the permafrost thaws. The image below pictures permafrost decline as foreseen by the IPCC in AR5. 

Obviously, rapid decline of the sea ice will come with albedo changes that will also make the permafrost decline more strongly than the IPCC foresees, while they will also cause even more extreme weather events. One of the dangers is that huge amounts of warmer water will flow from rivers into the Arctic Ocean, as discussed below.

- Warmer Water From Rivers

More sunlight getting absorbed in the Arctic will accelerate warming of the Arctic Ocean directly, while there will also be warmer water flowing into the Arctic Ocean from rivers in Siberia and North America, fueled by stronger and longer heatwaves, storms and wildfires. 

map from: http://en.wikipedia.org/wiki/File:Rs-map.png

Above map shows that a number of large rivers in Siberia end up in the Arctic Ocean. Another large river is the Mackenzie River, which ends in the Beaufort Sea, north of Alaska, where sea surface temperatures of about 20°C (68°F) were recorded in 2013, as the image below illustrates.

Another area of concern, also marked with a purple oval in the image below, is located in the north of Canada.

More extreme weather events include heat waves, storms, floods and wildfires, all of which can contribute to more rapid warming of the Arctic Ocean.

The combined effect of all the above will be that methane that is now contained in the form of free gas and hydrates in sediments under the Arctic Ocean, can be expected to be increasingly released as the Arctic Ocean warms further.

- Methane 

Of the vast amounts of methane stored in the Arctic, much of it is prone to be released with further temperature rises, as discussed in this earlier post and in this earlier post. Cracks in sediments used to be filled with ice. Warmer water is now melting the ice that used to sit in cracks. This ice has until now acted as a glue, holding the sediment together. Moreover, the ice in the cracks has until now acted as a barrier, a seal, that prevented the methane contained in those sediments from escaping. In a video interview with Nick Breeze, Natalia Shakhova mentions a sample of sediment taken from the ESAS seafloor in 2011 that turned out to be ice-free to a depth of 53 m at water temperatures varying from -0.6˚C to -1.3˚C. Back in 2008, Natalia Shakhova et al. considered release of up to 50 Gt of predicted amount of hydrate storage as highly possible for abrupt release at any time.

The image below, based on data from the IPCC and the World Metereological Organization (WMO), with an added observation from a NOAA MetOp satellite image, illustrates the recent rise of methane levels and the threat that methane levels will continue to rise rapidly.

When looked at from a longer range of years, above image fits in the black square on the image below.

The image below shows exponential rise based on data of East Siberian Arctic Shelf (ESAS) releases alone, as discussed in an earlier post.

Non-linear rise is supported by the fact that methane's lifetime increases as more methane enters the atmosphere. As the image below shows, peak methane levels have been very high recently.

All these feedbacks can interact and amplify each other in non-linear ways, resulting in rapid and intense temperature rises, as illustrated by the image below.

Diagram of Doom - for more background, see Feedbacks

4. Runaway Global Warming

The threat is that such rapid temperature rises will appear at first in hotspots over the Arctic and eventually around the globe, while also resulting in huge temperature swings that could result in depletion of supply of food and fresh water, as further illustrated by the above image, from an earlier post, and the image below, from another earlier post.

Rapidly rising temperatures will cause stronger evaporation of sea water. Since water vapor is one of the strongest greenhouse gases, this can further contribute to the non-linear temperature rises pictured above.

In conclusion, the situation is dire and calls for comprehensive and effective action, as discussed at the Climate Plan blog.

Post by Sam Carana.

Methane rising through fractures

by Harold Hensel

Methane is colorless and odorless and it is right above us in the atmosphere.

In addition to other sources, methane has traveled from the Arctic and has blanketed most of the Northern Hemisphere.

The well-known sources are methane hydrates from the Arctic Ocean floor and methane coming from thawing permafrost.

There is also another less well-known source. During the geologic history of the Arctic area, tectonic plates have spread, crashed into each other and subducted under one another. Geologists call the Arctic a tectonic plate junkyard. There are numerous fractures in the earth's crust there.

A quote from earth scientist Malcolm Light: ‘Mantle methane formed from the reduction of oceanic carbonates by water in the presence of iron (II) oxides buried to depths of 100 km to 300 km in the Asthenosphere and at temperatures above 1200°C.’ This is a nonorganic source of methane formed near the earth's mantel. Katey Walter Anthony from the University of Alaska calls it geologic methane.

Vast reservoirs of methane have been created by chemical reactions and stored near the mantle under a lot of pressure for millennia.

The methane has had a route to the surface through the fractures in the earth's crust, but the fractures have been sealed over by ice. Now for the first time in human history, the ice sealing the fractures is thawing. Methane is rising through the fractures and into the atmo­sphere. This methane has migrated to the United States and is over us.

Harold Hensel, 

Cedar Rapids.

Earlier published as 
Letter to the Editor 
Cedar Rapids Gazette 
(without images)


Related

- Study: Geologic methane seeping from thawing cryosphere - by Marmian Grimes
http://uafcornerstone.net/study-geologic-methane-seeping-from-thawing-cryosphere

- Focus on Methane - by Malcolm Light
http://arctic-news.blogspot.com/2014/07/focus-on-methane.html

- Arctic Atmospheric Methane Global Warming Veil - by Malcolm Light, Harold Hensel and Sam Carana

http://arctic-news.blogspot.com/2014/06/arctic-atmospheric-methane-global-warming-veil.html

- Mantle Methane - by Malcolm Light

http://arctic-news.blogspot.com/2014/02/mantle-methane.html

Post by Sam Carana.

Permafrost thawing could accelerate global warming

"If the permafrost melts entirely, there would be 5x the amount of carbon in the atmosphere than there is now" - Jeff Chanton

Jeff Chanton, the John Widmer
Winchester Professor of
Oceanography at Florida State.

A team of researchers lead by Florida State University have found new evidence that permafrost thawing is releasing large quantities of greenhouse gases into the atmosphere via plants, which could accelerate warming trends.

The research is featured in the newest edition of the Proceedings of the National Academy of Sciences.

“We’ve known for a while now that permafrost is thawing,” said Suzanne Hodgkins, the lead author on the paper and a doctoral student in chemical oceanography at Florida State. “But what we’ve found is that the associated changes in plant community composition in the polar regions could lead to way more carbon being released into the atmosphere as methane.”

Permafrost is soil that is frozen year round and is typically located in polar regions. As the world has gotten slightly warmer, that permafrost is thawing and decomposing, which is producing increased amounts of methane.

Relative to carbon dioxide, methane has a disproportionately large global warming potential. Methane is 33 times more effective at warming the Earth on a mass basis and a century time scale relative to carbon dioxide.

Changes in plant community composition in the polar regions could lead to way more carbon being released into the atmosphere as methane

As the plants break down, they are releasing carbon into the atmosphere. And if the permafrost melts entirely, there would be five times the amount of carbon in the atmosphere than there is now, said Jeff Chanton, the John Widmer Winchester Professor of Oceanography at Florida State.

“The world is getting warmer, and the additional release of gas would only add to our problems,” he said.

Chanton and Hodgkins’ work, “Changes in peat chemistry associated with permafrost thaw increase greenhouse gas production,” was funded by a three-year, $400,000 Department of Energy grant. They traveled to Sweden multiple times to collect soil samples for the study.

The research is a multicontinent effort with researchers from North America, Europe and Australia all contributing to the work.

Methane emerges from warmer areas

As the year draws to a close, it's time to review where warming has occured most strongly in 2013. Surface temperature anomalies in November 2013 were 0.77°C, the highest global November anomalies on record. In November 2013, high temperature anomalies occurred in the Arctic, well over 9°C north and south of Novaya Zemlya.

Indeed, global warming is hitting the Arctic particularly hard, and some models have underestimated the pace at which this is occuring. Most heat goes into the oceans, which - due to the Gulf Stream - contributes to accelerated warming in the Arctic, where also less monitoring takes place than over land. Stefan Rahmstorf, Co-Chair of Earth System Analysis at the Potsdam Institute for Climate Impact Research, says at RealClimate:

A new study by British and Canadian researchers shows that the global temperature rise of the past 15 years has been greatly underestimated. The reason is the data gaps in the weather station network, especially in the Arctic. If you fill these data gaps using satellite measurements, the warming trend is more than doubled in the widely used HadCRUT4 data.

Where did warming occur most strongly in 2013? The red/orange areas on the image below shows surface temperature anomalies of more than 2°C for the year from December 13, 2012, to December 12, 2012.

As the image shows, temperature anomalies have hit Earth most strongly in the cryosphere, i.e.
- in Antarctica, as discussed at this post;
- on the Qinghai-Tibetan Plateau, as earlier discussed at this post;
- in the Arctic, as discussed below.

Over the past 90 days, the Arctic Ocean has shown surface temperature anomalies of over 5°C and in some spots over 8°C.

Looking at anomalies over longer periods can mask the occurrence of much higher anomalies on individual days. As an example, temperature anomalies of over 20°C were recorded over a large part of the Arctic Ocean on November 17, 2013. 

Baffin Bay, west of Greenland, has until now received little attention. High temperature anomalies over the past year show up on the top image. These high temperatures are the more striking given that a cold sea current runs through Baffin Bay, as shown on the image below. 

Methane has emerged strongly from areas that have warmed most in 2013. In August 2013, high concentrations of methane showed up over Siberia. High methane releases have further occurred in all three parts of the cryosphere mentioned above, i.e. from the heights of Antarctica, as discussed at this post, on the Qinghai-Tibetan Plateau, as earlier discussed at this post, and in the Arctic, as discussed in many posts at the Arctic-news blog.

Huge methane concentrations have featured over Baffin Bay recently. The animation below shows huge methane emissions emerging from Baffin Bay on December 1-2, 2013. The power behind these methane releases is strong enough to make it difficult for thicker ice to form in Baffin Bay. The animation below shows an area marked by a red rectangle where it looks like the water would have been covered with thicker ice, had there not been so much methane bubbling up in the area.

This area with very thin ice in Baffin Bay is further illustrated in the Naval Research Laboratory 30-day Arctic sea ice thickness animation below.

This constitues yet another feedback, i.e. methane bubbling up from the seafloor of the Arctic Ocean with a force strong enough to prevent sea ice from forming in the area. 

Post by Sam Carana.

CLIMATE REPORT'S HUGE OMISSION OBSCURES FULL DANGER

by Gary Houser

CLIMATE REPORT'S HUGE OMISSION OBSCURES FULL DANGER:

Grassroots Must Insist IPCC Include Massive Permafrost Carbon

"Across two decades and thousands of pages of reports, the world's most authoritative voice on climate science has consistently understated the rate and intensity of climate change and the danger those impacts represent, say a growing number of studies .......   The speed and ferocity of climate change are outpacing IPCC projections on many fronts, including CO2 emissions, temperature rise, continental ice-sheet melt, Arctic sea ice decline, and sea level rise. 

The IPCC’s overly conservative reading of the science ..... means governments and the public could be blindsided by the rapid onset of the flooding, extreme storms, drought, and other impacts associated with catastrophic global warming."

                              

—  Scientific American, "Climate Science Predictions Prove Too Conservative", Dec.6, 2012    [1]

The primary scientific report used by governments of the world to guide their policies on climate has failed to convey the full danger being created by release of greenhouse gases into the atmosphere. By focusing on human-generated carbon, the Intergovernmental Panel on Climate Change (IPCC) has ignored an even more threatening process now being triggered by those emissions. Rapid warming in the Arctic - where temperatures are rising twice as fast as the global rate - is thawing an incomprehensibly vast stockpile of nature's own carbon which has been trapped in ice for millenia. This threat is described in a new mini-documentary (entitled "Last Hours"  [2] ), the importance of which has been highlighted by leaders on the climate issue such as Al Gore.   [3]  

The scale of this threat is mind-boggling. There is over three times more heating power stored in this "permafrost" than that which has been caused by human greenhouse gas emissions since the beginning of the industrial age - and this refers only to that located on land (as opposed to the coastal seabeds). [4]  This stockpile includes super greenhouse gas methane, acknowledged even by the IPCC itself to be a stunning 86 times more potent than carbon dioxide as a warming agent over 20 years (with climate-carbon feedbacks). [5]   

Despite a formal appeal by scientists specializing in permafrost study that IPCC issue a special assessment drawing attention to this tremendous danger  [6], the recently released report neglected to do so. The French news agency Agence France-Presse reported that due to bureaucratic delays and a log-jam in the processing of cutting edge data, 

"the cut-off date meant the authors were unable to evaluate recent, but very worrying, studies that say methane trapped in ice-bound coasts in northeast Siberia is being released as seas warm, thus putting the greenhouse effect into higher gear."   [7]

This massive failure by IPCC means that governments world-wide have not been given adequate warning about how preciously little time may be left to prevent the crossing of a tipping point leading to unstoppable global catastrophe. By not addressing the unique consequences brought on by accelerated Arctic warming, the IPCC is in fact skewing the picture that needs to be presented.

"Arctic and alpine air temperatures are expected to increase at roughly twice the global rate .... A global temperature increase of 3 degrees Celsius means a 6 degrees Celsius increase in the Arctic, resulting in an irreversible loss of anywhere between 30 to 85 percent of near-surface permafrost."   [8]

Even worse, more cutting edge science (also not included in the IPCC report) reveals additional unsettling developments. Exposure to sunlight appears to speed up the rate of permafrost thaw: "...sunlight increases bacterial conversion of exposed soil carbon into carbon dioxide gas by at least 40 percent compared to carbon that remains in the dark." [9]   This thaw on land is being matched in the shallow coastal seabeds. Natalia Shakhova - who has helped lead numerous fact-finding missions along the coast of Siberia - reports that releases there are "now on par with the methane being released from the arctic tundra."  [10]  She also warns that these releases can be larger and more abrupt than those resulting from decomposition on land.

As previously frozen methane vents to the atmosphere, the warming it causes can thaw and release even more. This "feedback" is capable of escalating into a "runaway" chain reaction that humanity would be helpless to stop. This is the same methane that some scientists point to as a major factor in the most sweeping mass extinctions in earth's history - the PETM and the end-Permian, the latter of which decimated  90 percent of all life forms.   Whether this association can be absolutely proven or not (the scientific basis for its connection to the Permian is explored in the BBC documentary "The Day Earth Nearly Died"  [11] ), no one can credibly deny the immense power of this greenhouse gas. 

By omitting this crucial information, policymakers are being dangerously lulled into believing there is more time to act - and less urgency - than what is in fact the case. At precisely the moment when the world needs the most unambiguous and emphatic warning from the scientific community - a moment which may not afford humanity any second chance to recover and correct course - it is nowhere to be found.  

Methane plumes rising from the seafloor

Over the years, the IPCC has been wrong numerous times in its projections. According to Scientific American:

"In the 2007 report, the IPCC concluded the Arctic would not lose its summer ice before 2070 at the earliest. But the ice pack has shrunk far faster than any scenario scientists felt policymakers should consider; now researchers say the region could see ice-free summers within 20 years."  [12]  

As the opening quote states, this pattern has persisted regarding several aspects of the issue. Given this history, it is not surprising the current IPCC report is again "behind the times" on the very day it is published.  In the short time following its release, a large number of experts on sea level rise are already saying that the IPCC projections are too cautious and conservative.  [13] 

Originally created with a mission to provide government bodies with un-biased scientific facts on climate disruption in order to inform the process of policymaking, the IPCC process has become seriously impaired by a combination of internal problems and outside pressure. The result has been the production of reports that not only fail to keep up with the cutting edge of the science itself but are also tainted by a bias toward overly conservative assessments. 

The same key article in Scientific American describes the internal logjam: 

"Such assessments typically take five to seven years to complete in a slow, bureaucratic process: ......... a summary for policymakers, condensing the science even further, is written and subjected to a painstaking, line-by-line revision by representatives from more than 100 world governments – all of whom must approve the final summary document."   [14]  

Materials from scientists are only accepted for consideration after they have been peer-reviewed and published in a scientific journal. This process in itself can take up to three years. Then another requirement is that such materials cannot be submitted beyond an early cut-off date. The goal of instituting an orderly process is laudable, but the severe problem is that the pace of climate disruption is most assuredly accelerating. If vital information at the cutting edge of these frightening changes cannot make it through these hurdles in time, there is a huge gap of five or six years before it can be integrated into the next report.  

 A key example would be the definitive paper documenting the land-based permafrost feedbacks which asks IPCC to issue a special assessment. Not only was this request ignored, but this documentation was not even considered as it was published after the cut-off date. 

The current IPCC report is quite intimidating at over 2000 pages long. A solution to both problems of timeliness and excessive length is to make the IPCC process more nimble by tackling the various key components of climate disruption individually rather than combining them all into one ponderous document. An example would be a report strictly limited to Arctic issues. As the most rapidly warming region on earth - with profound impact on the global climate - it is entirely deserving of special attention.

The second major problem is that when the IPCC was first set up, a provision was inserted which provides government entities the so-called "right" to review and approve the official Summary for Policymakers - the most important section. As the incredibly wealthy fossil fuel lobby holds great power over many governments, this provision provides an opening to pressure those governments into weakening the language.  As such power was actively used to weaken segments of the last Summary in 2007, [15]  it cannot be ruled out that such was used again. Scientific research should not be censored by political entities, a point made eloquently by British expert on feedback dynamics David Wasdell:

"What comes out is that which is 'acceptable' ...... from science that is about six years out of date, and that becomes the basis for negotiation and decision-making. It is grossly inappropriate....... There are many pressures ..... not least the enormous profits that continue to be made from fossil fuels." [16]  

This provision should be put up for debate and stricken.    

fish skeleton on parched soil, credit: Will Sherman

There is a corrective action which can be taken. Precedent already exists for the IPCC issuing a "Special Report" on aspects of the issue it considers worthy of special attention. A recent example is one on the increasing frequency of extreme weather events. There is a powerful case behind the need to release a Special Report on the threat from permafrost thaw in the Arctic. But an institution this size does not move unless there is a strong and coordinated campaign aimed at raising the issue and applying some "push". All the grassroots environmental groups that have led the climate movement are now called to recognize the dire need to integrate this frightening issue into the framework of all thinking and strategizing. If this is not done, and governments around the world continue to ignore it, there is a high likelihood that all other climate campaigns will fail. 

Keystone XL Pipeline protest - photo taken Feb 13, 2013 - from: flickr.com/photos/tarsandsaction/ 

The valiant effort to oppose the tar sands pipeline must be continued. But this movement must recognize that the climate threats are not presenting themselves in single file - one at a time. Several dangers are simultaneously bearing down on humanity. The laws of physics driving these threats will not pause for political stagnation. If the governments of the world fail to see the sleeping giant awakening in the Arctic and adjust their collective sense of urgency accordingly, then it appears our fate is sealed. The laws of physics will run their course. We owe it to those generations that would inherit a devastated planet to do better than that.      

The prospect of humanity being blindsided by a tremendous - and perhaps even fatal - blow is unthinkable. There is no "Planet B" to turn to if the conditions necessary to support life on our present planet are wiped out. Our society places great trust in the scientific community. Faced by any threat of this magnitude, our assumption is that our scientists will fulfill their moral obligation, act on the precautionary principle, and give us ample warning. In this case, that trust is being violated. It is therefore up to concerned citizens everywhere to speak out, hold them accountable,  and insist that governments receive the warning that is needed. This dangerous and potentially suicidal omission must not be allowed to stand.  

Who stands up for the children? - screenshot from children against climate change protest video

"The eyes of the future are looking back at us and they are praying for us to see beyond our own time. They are kneeling with hands clasped that we might act with restraint, that we might leave room for the life that is destined to come."  — Terry Tempest Williams [17]

---

Gary Houser is a public interest writer and documentary producer focusing on climate issues and the "sleeping giant" of Arctic methane in particular, and based in Ohio in the U.S.  He is seeking to network with others with similar concerns re: permafrost thaw who work in the U.S. context. Current projects are:  persuading major enviro / climate groups to integrate Arctic permafrost thaw as a high priority issue into their campaigns, a specific grassroots campaign to pressure IPCC toward a Special Report, public hearing on Arctic issues in the U.S. Senate, production and broadcast of Arctic permafrost thaw documentary on one of the national TV networks in the U.S.   He can be contacted at:  garyhouser4@gmail.com   

---

SOURCE LINKS:  

1. http://www.scientificamerican.com/article.cfm?id=climate-science-predictions-prove-too-conservative
2. www.lasthours.org
3. Press release: Last Hours Film Raises Issue Of Global-Warming-Induced Extinction ...
4. Is Arctic Permafrost the "Sleeping Giant" of Climate Change? - NASA ...
5. New IPCC report released in 2013, at IPCC AR5 WGI Table 8.7
6. Press Release - National Snow and Ice Data Center (NSDIC)
7. Compiling latest climate report took 3 years; critics say that's too long ...
8. NSIDC Press Room: Press Release: UNEP report urges ...
9. Thawing Permafrost May Be 'Huge Factor' in Global Warming ...
10. Arctic seafloor methane releases double previous estimates
11. "The Day Earth Nearly Died" (BBC documentary) : http://youtu.be/4dhNEAu4wDo
12. http://www.scientificamerican.com/article.cfm?id=climate-science-predictions-prove-too-conservative
13. Experts say the IPCC underestimated future sea level rise ...
14. http://www.scientificamerican.com/article.cfm?id=climate-science-predictions-prove-too-conservative
15. Washington Post: U.S., China Got Climate Warnings Toned Down
16. Video: Envisionation Interview: David Wasdell On the IPCC & Scientific ...
17. Quote by Terry Tempest Williams: The eyes of the ... - Goodreads

Post by Sam Carana.

Methane and the risk of runaway global warming

By Andrew Glikson

A satellite picture reveals permafrost melting around Liverpool Bay in Canada’s northwest territories. NASA Goddard Space Flight Center

Research was published this week showing the financial cost of methane being released from Earth’s permafrosts. But the risks go beyond financial – Earth’s history shows that releasing these stores could set off a series of events with calamitous consequences.

The sediments and bottom water beneath the world’s shallow oceans and lakes contain vast amounts of greenhouse gases: methane hydrates and methane clathrates (see Figure 1). In particular methane is concentrated in Arctic permafrost where the accumulation of organic matter in frozen soils covers about 24% of northern hemisphere continents (see Figure 2a) and is estimated to contain more than 900 billion tons of carbon.

Methane, a greenhouse gas more than 30 times more potent than CO₂, is released from previously frozen soils when organic matter thaws and decomposes under anaerobic conditions (that is, without oxygen present).

Most of the current permafrost formed during or since the last ice age and can extend down to depths of more than 700 meters in parts of northern Siberia and Canada. Thawing of part of the permafrost has not yet been accounted for in climate projections.

The Siberian permafrost is in particular danger. A large region called the Yedoma could undergo runaway decomposition once it starts to melt. This is because elevated temperatures cause microbes in the soil to decompose, which causes heat, which creates a self-amplifying process.

Figure 1: Global distribution of methane hydrate deposits on the ocean floor. Naval Research Laboratory

Palaeoclimate studies of stalagmite cave deposits across Siberia indicate they grew faster during the warm periods 424,000 and 374,000 years ago, due to permafrost melt. At that time, mean global temperatures rose by approximately 1.5 degrees Celsius above pre-industrial temperatures. Thus Vaks et al state: “Growth at that time indicates that global climates only slightly warmer than today are sufficient to thaw extensive regions of permafrost.”

Evidence of melting of permafrost has also been reported from the dry valleys of Antarctica, where development of thermokarst (small surface hummocks formed as ice-rich permafrost thaws) has been reported, reaching a rate about 10 times that of the last ~10,000 years.

The mean temperature of the continents has already increased by about 1.5C. With sulphur aerosols masking some of the warming, the real figure may be closer to 2C.

Figure 2a: Vulnerable carbon sinks. CSIRO Global Carbon Project

Figure 2b: Global average abundances of
carbon dioxide and methane 1978-2011

Arctic air temperatures are expected to increase at roughly twice the global rate. A global temperature increase of 3C means a 6C rise in the Arctic, resulting in an irreversible loss of anywhere between 30 to 85% of near-surface permafrost. According to the United Nations, warming permafrost could emit 43 to 135 billion ton CO₂ (GtCO₂) equivalent by 2100, and 246 to 415 GtCO₂ by 2200.
The geologically unprecedented rate of CO₂ rise (~2.75 ppm/year during June 2012-2013) may result in faster permafrost collapse.

Already measurements along the Siberian shelf uncover enhanced methane release. In 2010 a Russian marine survey conducted more than 5000 observations of dissolved methane showing that more than 80% of East Siberian shelf bottom waters and more than 50% of surface waters are supersaturated with methane. Atmospheric methane levels (during glacial periods: 300–400 parts per billion; during interglacial periods: 600–700 ppb) have recently reached 1850 ppb – the highest in 400,000 years (see Figure 2b).

Hansen et al estimate that the rise of CO₂ forcing between 1750 and 2007 has already committed the atmosphere to between +2 and +3 degrees Celsius, currently mitigated in part by sulphur aerosols.

Figure 3: Change in average annual land surface temperature since 1750. Berkeley Temperatures

Hansen refers to the “Venus Syndrome”, drawing an analogy between the enrichment of Venus’ atmosphere in CO₂ (its atmosphere is 96.5% CO₂ and its surface temperature is 462C) and potential terrestrial runaway greenhouse effects. This needs to be placed in context.

On Earth, weathering processes and oceans draw down the bulk of atmospheric CO₂ to be deposited as carbonates. It’s therefore impossible for Earth to develop Venus-like conditions. But the onset of a hyperthermal – a huge release of carbon such as happened during the Paleocene-Eocene Thermal Maximum 55 million years ago, with an attendant mass extinction of species – is possible.

Figure 4. Estimates of fossil fuel resources and equivalent atmospheric CO2 levels, including (1) emissions to date; (2) estimated reserves, and (3) recoverable resources (1 ppm CO2 ~ 2.12 GtC). Hansen, 2012, figure 1; http://www.columbia.edu/~jeh1/mailings/2012/20120127_CowardsPart1.pdf

Extraction and combustion of the current fossil fuel reserves (more than 20,000 billion tonnes of carbon – Figure 4) would inevitably lead to a hyperthermal commensurate with or exceeding the PETM. If that happens, CO₂ would rise to above 500ppm (see figure 4), temperature would rise by about 5C (figure 5) and the polar ice sheets would melt – it’s a future we could face if emissions continue to accelerate.

Figure 5: Growth in CO2 and CO2 equivalent (CO2+CH4) during the Pleistocene and the Holocene. IPCC AR4

Not that the above features too much in the Australian elections, where the reality of climate change has been replaced with pseudoscience notions, including by some who have not consulted basic climate science text books, and by hip-pocket-nerve terms such as “carbon tax”, “emission trading scheme” or “direct action”. The proposed 5% reduction in emissions relative to the year 2000 represent no more than climate window dressing.

Nor are coal exports mentioned too often, despite current exports and planned future exports, which represent carbon emissions tracking toward an order of magnitude higher than local emissions.

According to Dr Adam Lucas of the Science and Technology Studies Program at University of Wollongong, Australia (with ~0.3% of the global population) currently contributes domestic emissions of about 1.8% of global emissions. The total domestic and overseas consumption of Australian coal is responsible for more than 2% of global emissions. Plans to triple or even quadruple coal export volumes over the next 10 years would raise Australia’s total contribution to global GHG emissions to toward 9% to 11% by 2020 – an order of magnitude commensurate with that of Middle East oil.

Which places the “Great moral challenge of our generation” in perspective.

Andrew Glikson does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.

This article was earlier published at The Conversation.

Is the permafrost's integrity breaking down?

The chart below shows very high methane levels over Antarctica in April and May 2013. High levels of methane over Antarctica were recorded before in 2013, as described in an earlier post at the methane-hydrates blog.

Meanwhile, a methane reading of 2475 ppb was recorded on April 26, 2013, appearing to originate from the Himalayan Plateau, as illustrated by the image below.

Recurring high readings could indicate that methane is bubbling up through the permafrost, both in Antarctica and on the Himalayan Plateau.

Loss of the integrity of the permafrost is particularly threatening in the Arctic, where the sea ice looks set to disappear within years, resulting in huge albedo changes in summer. Decrease of surface reflectivity results in increases in absorption of energy from sunlight and decreases in shortwave radiation in the atmosphere. The latter results in lower photo-dissociation rates of tropospheric gases. Photo-dissociation of the ozone molecule is the major process that leads to the production of OH (hydroxyl radical), the main oxidizing (i.e., cleansing) gas species in the troposphere. A 2009 NASA study projects this to lead to a decrease in OH concentrations and a weakening of the oxidizing capacity of the Arctic troposphere, further increasing the vulnerability of the Arctic to warming in case of additional methane releases.

Levels of greenhouse gases such as carbon dioxide and methane are already very high in the Arctic atmosphere, while large quantities of black carbon get deposited on snow and ice, further contributing to the albedo changes. This threatens to result in rapid summer warming of many parts of the Arctic Ocean with very shallow waters. Additionally, rivers can bring increasingly warm water into those shallow seas in summer, adding to the threat that heat will penetrate the seabed that contains huge quantities of methane.



Above image, earlier included in an animation at the Arctic-news blog, shows methane concentrations on January 23, 2013, when a reading of 2241 ppb was recorded in the Arctic.

Analysis of sediment cores collected in 2009 from under ice-covered Lake El'gygytgyn in the northeast Russian Arctic suggest that, last time the level of carbon dioxide in the atmosphere was about as high as it is today (roughly 3.5 to 2 million years ago), regional precipitation was three times higher and summer temperatures were about 15 to 16 degrees Celsius (59 to 61 degrees Fahrenheit), or about 8 degrees Celsius (14.4 degrees Fahrenheit) warmer than today.

As temperatures rose back in history, it is likely that a lot of methane will have vented from hydrates in the Arctic, yet without causing runaway warming. Why not? The rise in temperature then is likely to have taken place slowly over many years. While on occasion this may have caused large abrupt releases of methane, the additional methane from such releases could each time be broken down within decades, also because global methane levels in the atmosphere were much lower than today.

In conclusion, the situation today is much more threatening, particularly in the East Siberian Arctic Shelf (ESAS), as further described in the earlier post methane hydrates.

Above post is an extract of the full post at the methane-hydrates blog.