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Arctic Methane Emissions ‘Certain to Trigger Warming’

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As climate change melts Arctic permafrost and releases large amounts of methane into the atmosphere, it is creating a feedback loop that is "certain to trigger additional warming," according to the lead scientist of a new study investigating Arctic methane emissions. 

The study released this week examined 71 wetlands across the globe and found that melting permafrost is creating wetlands known as fens, which are unexpectedly emitting large quantities of methane. Over a 100-year timeframe, methane is about 35 times as potent as a climate change-driving greenhouse gas than carbon dioxide, and over 20 years, it's 84 times more potent.

Permafrost terraces in Alaska.
Credit: U.S. Fish and Wildife Service Alaska/flickr

Methane emissions come from agriculture, fossil fuel production and microbes in wetland soils, among other sources. The study says scientists have assumed that methane emissions from wetlands are high in the tropics, but not necessarily in the Arctic because of the cold temperatures there. 

But a spike in global methane concentrations in the atmosphere seen since 2007 can be partly traced back to the formation of fens in areas where permafrost once existed, according to the study, led by University of Guelph (Ontario, Canada) biology professor Merritt Turetsky.

The methane emissions stemming from melting permafrost could be critical to determining how fast the climate will change in the future.

“Methane emissions are one example of a positive feedback between ecosystems and the climate system,” Turetsky said. “The permafrost carbon feedback is one of the important and likely consequences of climate change, and it is certain to trigger additional warming.”

Warming and thawing permafrost stimulate methane release, which enhances the greenhouse effect, creating a feedback loop, she said.

“Even if we ceased all human emissions, permafrost would continue to thaw and release carbon into the atmosphere,” Turetsky said. “Instead of reducing emissions, we currently are on track with the most dire scenario considered by the IPCC. There is no way to capture emissions from thawing permafrost as this carbon is released from soils across large regions of land in very remote spaces.”

The Intergovernmental Panel on Climate Change projected in its fifth assessment on climate change report that the earth’s average temperatures could warm by as much as 8.64°F above 1986-2005 temperatures if nothing is done to curb greenhouse gas emissions.

Coastal erosion reveals the ice-rich permafrost underlying the Arctic Coastal Plain in the National Petroleum Reserve in Alaska.
Credit: USGS

Turetsky’s study shows that fens in the northern latitudes created when permafrost thaws can have emissions similar to wetlands in the tropics. Emissions from fens are generally higher than bogs and some other wetland types because fens, fed by groundwater, have higher nutrient levels and more grasses than bogs, leading to more methane production.

“Our study highlights that northern wetlands without permafrost emit more methane than wetlands with permafrost,” U.S. Geological Survey research ecologist and study co-author Kimberly Wickland said.

“When permafrost is absent, wetlands can be more connected to groundwater, allowing for wetter conditions — the main ingredient for methane production,” she said. “It is possible that methane emissions from wetlands will continue to increase with continued permafrost thaw, but that will depend primarily on whether wetlands stay wet. If they dry, then methane emissions will decline.”

Gavin Schmidt, a climate scientist at NASA's Goodard Institute for Space Studies in New York and not part of the study, said it's too soon to draw conclusions about how much wetland methane emissions will impact global warming, though scientists widely agree that the amplified feedback is generally going to increase. 

The paleo record shows that the Arctic was several degrees warmer during the last interglacial period 120,000 years ago, and there is no evidence of increased levels of methane in the atmosphere during that period, he said. 

"It's not to say at some point it won't become an issue," Schmidt said, adding that there is evidence of many "methane burps" across the globe in the very distant past. 

"The planet is very capable of surprising us," he said.

By surveying many wetland sites across the globe as Turetsky and her team have, scientists can gain a much broader understanding of the source of methane emissions from melting permafrost and their role in the feedback loop, Schmidt said. Many previous studies have examined just a single site whereas Turetsky's team examined numerous sites across the globe. 

"The work these people are doing in terms of trying to synthesize that information and bring it all together, I think it's certainly going in the right direction," he said. 

Turetsky's study, “A synthesis of methane emissions from 71 northern, temperate, and subtropical wetlands,” was published this week in the journal Global Change Biology.

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Comments

By Ken Lundgreen (94109-9052)
on May 2nd, 2014

I don’t think the theory of sudden release by the clatrate gun applies to these wetlands where there are no large stores clathrate hydrate sequestered methane. But; increased concentrations in the atmosphere & water does act as as a positive feedback itself & thus in that regard contributor to the next chain reaction clathrate burp gun that will burn the sky & suck oxygen out of the oceans leading to hydrogen sulfide production & release that will kill off oxygen breathing organisms.

Reply to this comment

By Robert Atack (5391)
on May 2nd, 2014

>and over 20 years, it’s 84 times more potent.<
BUT methane only lasts in the atmosphere for about 8 years, so why add another 12 years to the equation?
This from a friend
If anyone can demonstrate where this analysis is incorrect I would be pleased to hear from them.

Kevin


There has been considerable discussion on Collapse of Industrial Civilisation about the warming effect of the total greenhouse gas content of the atmosphere.

In 2013 I woke up to the fact that the ‘official’ methane multiplier was way too low: like many people I accepted the ‘official’ figure without thinking.  And only very recently weeks have I woken up to the fact that the entire basis for most assessments is phony.

I have no access to a suitably equipped laboratory and can only present this case as scientifically as possible from a theoretical perspective.

1. If we take a tube containing methane and pass a ray of the right spectral wavelength through it the methane molecules will absorb energy and reradiate it randomly, resulting in a lower reading at a sensor at the end than would occur if the tube were a vacuum tube (cf. the work of Tyndall, 1859).

2. If we repeat the procedure one year later, the methane will absorb and reradiate exactly the same amount of radiation.

3. In the atmosphere methane molecules can be oxidised, primarily by hydroxide ions OH- or OH radicals OH. , which are generated by the splitting of water molecules by ionizing agents

4. The effect in the atmosphere is to progressively convert CH4 into CO2 via a ‘decay’ curve.

5. Since CH4 in the atmosphere has a very much higher greenhouse effect than CO2 (well over 100 times as great as CO2 in the short term), evaluation of an individual molecule’s overall warming potential poses a considerable problem; a complex integration of ‘area under the graph’ is necessary, and even that cannot be readily achieved because the rate of oxidation can vary hugely, depending on the availability of OH ions and radicals, which are themselves subject to variation y many other factors. 

6.  For a long time the relative warming effect of CH4 was described as ‘about twenty times that of CO2’, while an ‘official’ factor of 23 was assigned. In 2013 the ‘official’ factor was raised to 34. This was on the basis of a very high initial warming factor which eventually decline to a value of 1.

7.  Methane is generated by natural systems in enormous quantities whenever organic matter is decomposed in situations which lack oxygen: since solids and liquids are around one-thousand times as dense as gases, running of oxygen tends to be a commonplace occurrence wherever dead organic matter accumulates. Methane is also generated in other biological situations, and as a result of ancient deposits of organic matter in sedimentary rocks being subject to extreme heat -the gas often associated with oil and coal.

8. For most of the time the prior to the Industrial Revolution the generation of methane and its oxidation were roughly in balance. There was always a relatively small amount of methane in the atmosphere: the generally accepted figure is around 750ppb immediately prior to industrialism. That methane was contributing to maintenance of the relatively stable temperatures of the Halocene.

9.  Since practically every molecule of CH4 that was in the atmosphere that was oxidised to CO2 was replaced by another, the warming effect did not change and was always the product of the instantaneous absorption and reradiation rate, as measured in a tube in a laboratory. Although individual molecules were removed as per the ‘decay’ curve, the overall amount of CH4 did not decline as suggested by accepted climate modelling factors of 23 and 34. 

10.  In recent times atmospheric methane levels have been somewhat above twice the pre-industrial level, in the range 1500 to 1800ppb or 1.5 to 1.8ppm. Higher levels of the order of 2.3ppm have been reported in arctic regions, so a fair approximation of current atmospheric methane is 2ppm.

11. Since release of methane constantly replaces (or exceeds) methane oxidation, we must use the instantaneous warming factor of something in excess of 100. Doing so gives us a CO2 equivalence of 200ppm.

12. Adding the CO2 equivalence of CH4 of 200ppm to the 400ppm CO2 gives us a total CO2 equivalence of 600ppm for just carbon dioxide and methane.

13. If we apply the same logical argument to other ‘minor’ greenhouse gases we discover that we are at well over 700ppm CO2 equivalence.

14. If we consider the state of affairs prior to the Industrial Revolution we had approximately 0.75ppm CH4, which gives an equivalence of 0.75 x 100 = 75ppm CO2. That gives us a total equivalence of 355ppm for CO2 plus CH4. Other components of the atmosphere would have taken the total CO2 equivalence to something around 400ppm CO2, as compared to the current value in excess of 700ppm

15. That suggests we currently have about twice the greenhouse gas warming forcing compared to a little over 200 years ago. Clearly that level of forcing is having the disastrous effects on the natural world we have been witnessing over in recent times, and we cannot be surprised that we have triggered numerous positive feedbacks.

16 Since the prime purpose of government is to facilitate the looting-and-polluting of the commons by corporations and opportunists in order that Ponzi financial and economic arrangements can be maintained in the short term, and the gate-keepers of the commercial media require business-as-usual, of no discussion of the almost certain runaway nature of climate change is publicly allowable.

Kevin Moore   8th March 2014

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By Dave (Basking Ridge, NJ 07920)
on May 5th, 2014

Your friend may want to know that the GWP of a GHG is defined relative to an equal mass of CO2 emissions; whereas atmospheric concentrations are typically expressed on a volume basis. This means that his estimates of CO2 eq for methane as expressed here are about 2.7 times too high due solely to failing to compensate for mass differences.

To try to respond to some of your question - the atmospheric residence time is defined as a characertistic or decay time as opposed to a time when it has all gone.

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By Tony
on May 6th, 2014

I asked, essentially, this question on Real Climate. I received an answer from Gavin Schmidt:

“The impacts over a single year are small (tiny even) because of the inertia of the climate system which integrates the forcings over time. 20 years is pretty much a minimum at which it makes any sense, but as you can read in section 8.7 of AR5, there are many problems with GWP as a concept.”

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By Chena River (Fairbanks, AK 70030)
on May 7th, 2014

You should put this at a 4th grade reading level for everyone in the world to understand the importance of the data.

Reply to this comment

By Tony
on May 3rd, 2014

“But a spike in global methane concentrations in the atmosphere seen since 2007”

The resumed rising trend since 2007 (after levels of methane were steady for several years) is worrying, but it isn’t a “spike”. I think we need to be careful about such descriptions as they can render the whole story bad, in the minds of some people.

Reply to this comment

By harry bailey (spring, texas, 77389)
on May 4th, 2014

and after the oceans warm up, there is a vast amount of frozen methane off of California that will melt, its started already.

Reply to this comment

By idic5
on May 4th, 2014

” it is creating a feedback loop that is “certain to trigger additional warming,” according to the lead scientist of a new study investigating Arctic methane emissions. “

Is this feedback loop the same as a runaway loop?

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By Robin Datta (Fresno CA 93720)
on May 5th, 2014

Permafrost methane is one thing; a “burp” from the East Siberian Arctic Shelf could be quite another, considering the ample opportunity for it: a 40 year lag from greenhouse gas emissions to the effects and a 400 ppm CO<sub>2</sub> corresponding to a 4°C rise by paleoclimate records.

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By michael
on May 6th, 2014

The IPCC report excludes emissions from permafrost in the warming scenarios of WG1. This is clearly stated. Then in WG 3 it produces the emission reduction targets to avoid the warming described in WG1 but forgets to say that permafrost etc is excluded from those emission reduction budgets.

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By Tom Mallard (BELLEVUE, WA 98008)
on May 7th, 2014

There is no reason to downplay the role methane emissions in the Arctic will contribute to continued warming regardless of what humans do about the other greenhouse emissions.

This study didn’t mention the clathrates deposits and those emissions have grown exponentially over the past 5-years and contain 1,000+ gigatons of reserves to contribute beyond anything land permafrost thawing contributes.

Also, when looking at past records over time, methane becomes CO2 with aging so how do you tell after it’s converted to CO2 that the origin was CH4?

Please regard this as a logic fallacy to not recognize that identification of the source of CO2 found in ice-cores needs to differentiate between whether it originated as CH4 or not, or it must be assumed during a heating event that methane was indeed released in some significant quantity to control risks.

With that uncertainty, it’s not rational to dismiss this source of greenhousing when the ocean deposits and the land-based outgassing are both increasing exponentially with each warming season. CARVE has identified areas of ocean some 90-miles in diameter outgassing CH4 like soda water that began as centimeter wide pipes widely dispersed so there is ample reason to be worried.

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