Permafrost 101: Why We Need To Account For Thawing Ground In Climate Projections

by Roz Pidcock, via Carbon Brief

Melting permafrost in the Arctic could push the earth towards climate change that is “irreversible on human timescales”, according to a new report…. Here’s our quick guide to what you should know about melting permafrost.

The report, by the United Nations Environment Programme (UNEP), says billions of tonnes of carbon once locked up in permafrost could be released into the atmosphere this century – accelerating global warming. But how much might be released, and how quickly? These questions are still being debated in the scientific community, which means that it’s sometimes hard for media coverage to strike the right balance when discussing how significant the effect could be.

1. What is permafrost?

Permafrost is the name given to permanently-frozen ground in high latitudes. Permafrost acts like a lid, locking frozen carbon deposits deep below ground. The upper layer of permafrost thaws and re-freezes naturally each year. As the carbon thaws, microbes degrade it – a process that releases carbon dioxide and methane.

As atmospheric temperatures rise – due mainly to human activity – heat penetrates deeper into the ground than before. This leads to more permafrost thawing, and more carbon being released to the atmosphere.

2. What does that have to do with climate change?

Scientists are concerned that carbon dioxide and methane released into the atmosphere from permafrost will mean more global warming. Methane is a powerful greenhouse gas – around 25 times more effective at trapping heat than carbon dioxide over a 100-year cycle.

What’s more, this additional warming can create a vicious circle. Extra warming thaws more permafrost, leading to further warming – and so on. Scientists call a self-reinforcing warming cycle like this a positive feedback.

This has important consequences for limiting climate change – it’s already looking increasingly unlikely that warming can be limited to two degrees above pre-industrial levels – the internationally accepted target. An additional source of greenhouse gases from permafrost further reduces the chances of hitting that target.

Permafrost Feedback

The positive feedback from thawing permafrost amplifies existing atmospheric warming due to human activities. Source: UNEP report “Policy Implications of Warming Permafrost”.

3. Don’t scientists know about melting permafrost already?

Yes, scientists have already raised concern that rising temperatures could thaw part of the vast reservoir of frozen methane along continental shelves and undersea in the Arctic and, more recently, in the Antarctic.

But there is a lot of uncertainty about how big the global reservoir is and how much of it is thawing, which we wrote a bit more about here. About 60 per cent of methane in the atmosphere results from human activity, like agriculture and landfill. So far, only a small amount is from melting permafrost. The remaining 40 per cent is released naturally from wetlands.

All of this uncertainty means that the Intergovernmental Panel on Climate Change has been unable to properly account for thawing permafrost in its projections for future global warming.

4. What does the new UNEP report say?

The new report is a synthesis of the most up-to-date scientific research. It says that permafrost covers a quarter of the northern hemisphere and currently stores around 1700 billion tonnes of carbon – almost twice the amount currently present in the atmosphere.

Between 43 and 135 billion tonnes of methane could be released by 2100 as permafrost thaws, according to the report, and by 2200 that number could reach 246 to 415 billion tonnes. These emissions could start now but continue for many centuries, influencing both the short term and long term climate.

Temperatures in the high latitudes are projected to rise twice as fast as the global average. The report warns a three degree world, or six degrees in the Arctic, could melt 30 to 85 per cent of near-surface permafrost. As well as affecting the climate, this would permanently affect local hydrology, alter habitats and could damage critical infrastructure built on melting ground.

Permafrost _thaw _2100

One model projection indicates a 59% loss in near-surface permafrost area by 2100 for the IPCC A1B scenario Source: UNEP report “Policy Implications of Warming Permafrost”.

5. Will this push the earth past a tipping point?

The UNEP report warns that the release of carbon from permafrost is essentially irreversible on human timescales. Some media coverage of the UNEP report has suggested that carbon released from melting permafrost could push the climate past a tipping point.

A climatic tipping point is a threshold beyond which the climate undergoes a shift from one physical state to another, and could include things like thawing permafrost, melting of the Greenland ice sheet or the dieback of the Amazon rainforest.

While scientists are confident that such tipping points exist in theory, predicting when they might occur and measuring progress towards them cannot be done with certainty. Research is beginning to provide a clearer picture though – a recent study suggests that some tipping points in the climate may even occur below two degrees of warming.

6. So what should be done about melting permafrost?

To reduce some of the uncertainty on this subject, the report recommends a special IPCC assessment into how emissions from melting permafrost will influence global climate. Countries with substantial permafrost should also create national networks to adequately monitor permafrost carbon release and develop adaptation plans to estimate the costs and risks of permafrost thaw, says the report. All this will help scientists factor permafrost feedbacks into future projections of the climate, as well as set emissions targets to reduce global warming.

Looking ahead

Methane from permafrost is likely to be an important source of carbon emissions on timescales of hundreds or even thousands of years, and it’s important that the feedbacks are better understood so they can be factored into climate projections. But carbon dioxide emissions from burning fossil fuels continue to be the biggest obstacle to stabilising global climate in the short term.

As Professor David Archer, expert on the impact of methane on global climate at the University of Chicago, explained to Carbon Brief recently, if the problem of excess carbon dioxide emissions is fixed, methane is unlikely to be much of an issue.

Roz Pidcock writes about climate science and media coverage for Carbon Brief. This piece was originally published at Carbon Brief and was reprinted with permission.

23 Responses to Permafrost 101: Why We Need To Account For Thawing Ground In Climate Projections

  1. Mike Roddy says:

    Nice summary, Roz, thanks.

    A scientist from Berkeley told me last week that there has been another surprise: microbes coming back to life, in ground that has been frozen for 10,000 years. This adds considerable methane emissions to previous projections. The paper he referred to has not been published, but if anyone has information here it would be interesting to hear about it.

  2. prokaryotes says:

    I assembled a bit on “Flooded soild”, which touches briefly on permafrost thawed soils too. The main culprit here which i read a bit about (don’t have link now) is the forming of thermocast lakes, which could become a substantial Greenhouse gases emitter. But it varies highly on the soil type, organic matter and such.

    Despite the clear effect of increasing temperatures on the rate of methanogenesis, the actual impact of global warming on methane production rates in wetlands and permafrost regions is highly unpredictable. Because methanogenesis requires anoxic conditions, any drying of flooded soil environments would both decrease methane production and increase methane oxidation, reducing overall methane emissions. Alternatively, warmer climates could increase growing seasons, which would increase methane emissions (Sylvia, 2005).

  3. prokaryotes says:

    Modern thermokarst lake dynamics in the continuous permafrost zone, northern Seward Peninsula, Alaska

  4. Wes says:

    Very cautious and understated article which minimizes the very dangerous mess we’ve gotten ourselves into. Two degrees is “increasingly unlikely”? Gimme a break. There is no way to hold 2 deg and 3 deg would require massive action starting now, which shows no sign of happening. There seem to be a large number of positive feedbacks that are kicking in which were discounted or not understood in the early research.

    I’m with the authors at the AGU Conference that titled their paper “Is Earth F**ked?” If scientists want to get anyone’s attention, that’s the way they have to talk.

  5. David Moore says:

    I agree with Wes that CO2 is adding 2 plus ppm per year and this rate is increasing led by China and India. This is without permafrost methane added in. Limiting rise to 2 or 3 degrees C seems very unlikely. Stop sugar coating the problem!

  6. Jim Baird says:

    NASA points out “the Earth’s poles are warming faster than the rest of the planet because of energy in the atmosphere that is carried to the poles through large weather systems.” Hence we have the threat of methane releases from the permafrost and icecap melting.

    These systems are driven in the main by sea surface heat which can be sapped to produce energy with OTEC. The more energy produced the more the ocean surface is cooled.

    Part of this heat is converted to mechanical energy in the process but the bulk, 20 times the energy produce, is moved to the deep water heat sink that has a lower coefficient of exansion.

    Kevin Trenberth, points out in a paper, “An imperative for climate change: tracking Earth’s global enery”, “The warming required to produce 1 mm SLR if the heat is deposited in the top 700 m of the ocean can take from 50 to 75 1020 J, or 110  1020 J if deposited below 700 m depth.

    In other words you can move heat from the surface to the depths with OTEC to counter 50 percent of current sea level rise due to thermal expansion.

    By sapping the heat of hurricanes you also diminish the amount of heat that would be moved from the tropics towards the poles and thus forestall melting.

    This is the lesson of Hurricane Sandy, no one apparently cares to learn.

  7. Probably not a good idea if we have to disturb the thawing soil in the process…

  8. Jeb says:

    Did the Koch brothers buy Think Progress??? Holy smoke, what a smokescreen. There are more than twenty KNOWN feedback loops, permafrost is arguably only the third worst, the numbers are WAY understated (trillions of tonnes TOTAL), the wording is lamely lowballing, some tipping points will be exceeded in 5 to 10 years, and I can’t state ALL that is wrong with the article in this comment, but I am going to do a post on my site refuting this article, stating the actual reality of the dangers of feedback loops…(there are already some posts out there, even about their prior article on permafrost)…

  9. Jeb says:

    Regarding prior comment, the total planetary methane stored is estimated at 20 to 26 TRillion tons. > Link to summary of planetry methane

  10. Paul Klinkman says:

    Every single time that I see some projection into 2100 I wonder, does this projection take positive feedback loops into account? If it doesn’t, we need that explicitly stated. Positive feedback is the norm in this field, and to assume otherwise without stating your evidence-free assumption creates a misperception.

    If I tell you that you’re getting a 7% loan, and I extrapolate 7% for one century linearly to get 700% interest, that would be financial malfeasance on my part. (Gag line: and so I’d be hired by a big bank in an instant.)

  11. Greatgrandma Kat says:

    Your opening comment was really uncalled for. If thats how you really feel about this site none of us here will miss you if don’t post here again. All of us here realise the understated mess we are in, but without good science we are lost. Speculation without data is just that. The real fight is against the denial machine that has delayed action and is still promoting the burning of fossil fuels.

  12. Greatgrandma Kat says:

    Don’t act like your the only one with this information or that you are better informed than anyone else. Working together is the only way we can move forward.

  13. David Goldstein says:

    QUESTION???- does the 1700 billion tonnes of carbon ‘stored beneath the permafrost’ include the methane clathrates or not. It seems that there are two distinct ‘carbon pools’ when speaking of permafrost- one is organic carbon that is simply part of the frozen soil that will be released as ‘the lid’ of permafrost thaws. The other are the actual methane clathrates that tend to be stored in shelves under freezing water. So…does the 1700 billion tonnes incude the clathrate or is that a whole other carbon pool?

  14. Solar Jim says:

    RE: “David Archer, expert on the impact of methane on global climate at the University of Chicago, explained to Carbon Brief recently, if the problem of excess carbon dioxide emissions is fixed, methane is unlikely to be much of an issue.”

    If this is actually the statement of D. Archer then I conclude he does not understand the basics of climate change.

  15. prokaryotes says:

    Well, the idea is basically to have the Biochar act as a sponge for the Greenhouse gases in that soil.

  16. prokaryotes says:

    If you read the comments here you see that D. Archer’s studies are not without a pitch of controversy.

  17. Superman1 says:

    But, even titling the paper as a question is misleading. It makes it appear as though there is some doubt remaining.

  18. Superman1 says:


    Good observation. Unfortunately, this is the reality of how climate change is reported in the official studies. Kevin Anderson shows how the major climate change reports consistently understated carbon emissions PAST, present, and future, to soften the dire straits we are in. But, even Anderson’s relatively harsh conclusions are based on computations that don’t take into account the positive feedbacks. I have sufficient experience with nonlinear dynamical systems to know the devastating impact positive feedbacks can have on system performance once triggered. And, we are observing these feedbacks coming into play as we speak, and they are all self-reinforcing.

    BTW, could you provide a listing of the twenty positive feedbacks that you mention. I would like to have those for future reference. Even the few I have been focusing on are grim enough; a more complete set would be of real value.

  19. Superman1 says:

    I don’t think any of the models include positive feedbacks. Even Kevin Anderson, with his supposedly harsh forecasts, mentions off-handedly that inclusion of positive feedbacks in the models would make the situation worse.

    This is all a game. We’re seeing numerous positive feedbacks come into play already. No one has convinced me that we can stabilize the temperature at the present 0.8 C given the feedbacks we are already observing, with some of the Arctic methane feedbacks starting to accelerate.

    Nobody likes to be told they have Stage 4 incurable cancer, and the average remaining time is six months. That’s where we are. Yes, a magical cure for the climate change that removed copious amounts of CO2 from the atmosphere in a short time would ameliorate the problem, just as a magical cure for Stage 4 cancer would prolong life. What’s the odds of either happening?

  20. Superman1 says:

    Archer et al understand the problem only too well. Unfortunately, he and almost every other climate change researcher get their funds directly or indirectly from the government. The last thing the government (and its industry supporters) wants is for the citizenry to fully understand the catastrophe we are facing. So, all these climate change reports tend to include underestimates (like not including positive feedback effects in the climate models, or underestimating future carbon emissions, etc), and usually end with patently phony ‘glimmers of hope’. If the reality of what we actually face sunk in with the citizenry at large, I think the resulting chaos and retributions would be unimaginable.

  21. Joan Savage says:

    Interesting about methane oxidation.

    In nature one of the better documented biotic pathways is methane > methanol > formaldehyde > formic acid. The formic acid end point is a relatively stable weak carbonic acid found in soils and emitted to the atmosphere by forests. If we are going to see an increase in formic acid and the intermediate metabolites, methanol and formaldehyde, understanding what those might do would be a help.

    Obviously that contrasts to non-biotic methane oxidation.

  22. EDpeak says:

    Look forward to hearing what the latest science says BUT leaders cannot claim that this is “new” – we have had warnings for many years, I have been talking about it for more than a half decade..see by google this one:

    Friday 01 September 2006

    “Changing climate: ‘Compost effect’ may cause global warming to reach crisis point in 2050 ”

    And not just methane emissions higher but also more CO2 in the atmosphere:

    rofessor Peter Cox, of Exeter University, told the Royal Geographical Society annual conference that temperatures could rise 8C by 2100 because of a “compost effect” which could see carbon dioxide levels increase 50 per cent faster than previously estimated.

    Currently, around one quarter of carbon emissions are absorbed by the soil and one quarter by the oceans. It had previously been assumed that these proportions would remain the same. But Professor Cox said that global warming is damaging the soil’s ability to absorb carbon emissions.

    It’s funny the article talks about “currently” CO2 beign 280…that was “only” 6 years ago…but in political terms it’s a long six years ago so corporations can’t claim they didn’t know about the effects of warming soils until 2012…it’s been known this is yet another Positive Feedback danger that the science pointed to as likely what we face “unless urgent action is take” they said in 2006…and said in 2007, and 2008…and so on ad nausium to this day…we need to complain less and get *active* as citizens, without that our profits-based and perpetual-growth based economies around the wolrd guarantee that each climate “summit” will be “far too little, far too late” (at best) and sugarcoated business as usual (or worse than usual) otherwise..