Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.


Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup


All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Home Arguments Software Resources Comments The Consensus Project Translations About Support

Twitter Facebook YouTube Mastodon MeWe

RSS Posts RSS Comments Email Subscribe

Climate's changed before
It's the sun
It's not bad
There is no consensus
It's cooling
Models are unreliable
Temp record is unreliable
Animals and plants can adapt
It hasn't warmed since 1998
Antarctica is gaining ice
View All Arguments...

New? Register here
Forgot your password?

Latest Posts


Thawing of Permafrost Expected to Cause Significant Additional Global Warming, Not yet Accounted for in Climate Predictions

Posted on 16 December 2012 by John Hartz

This is a reprint of a press release posted by the United Nations Environment Programme (UNEP) on Nov 27, 2012.

Policymakers and Climate Scientists Must Monitor and Prepare for Large Carbon Dioxide and Methane Emissions from Permafrost, Says UNEP Report

Photo of permafrost exposure on the coast of Herschel Island, Yukon Territory

A scientist standing in front of an ice-rich permafrost exposure on the coast of Herschel Island, Yukon Territory (photo: Michael Fritz).

Permafrost covering almost a quarter of the northern hemisphere contains 1,700 gigatonnes of carbon, twice that currently in the atmosphere, and could significantly amplify global warming should thawing accelerate as expected, according to a new report released today by the UN Environment Programme (UNEP). 

Warming permafrost can also radically change ecosystems and cause costly infrastructural damage due to increasingly unstable ground, the report says.

The report, Policy Implications of Warming Permafrost seeks to highlight the potential hazards of carbon dioxide and methane emissions from warming permafrost, which have not thus far been included in climate-prediction modelling. The science on the potential impacts of warming permafrost has only begun to enter the mainstream in the last few years, and as a truly "emerging issue" could not have been included in climate change modelling to date. 

The report recommends a special IPCC assessment on permafrost and the creation of national monitoring networks and adaptation plans as key steps to deal with potential impacts of this significant source of emissions, which may become a major factor in global warming. 

"Permafrost is one of the keys to the planet's future because it contains large stores of frozen organic matter that, if thawed and released into the atmosphere, would amplify current global warming and propel us to a warmer world," said UN Under-Secretary General and UNEP Executive Director Achim Steiner. 

"Its potential impact on the climate, ecosystems and infrastructure has been neglected for too long," he added. "This report seeks to communicate to climate-treaty negotiators, policy makers and the general public the implications of continuing to ignore the challenges of warming permafrost." 

Most of the current permafrost formed during or since the last ice age and extends to depths of more than 700 meters in parts of northern Siberia and Canada. Permafrost consists of an active layer of up to two metres in thickness, which thaws each summer and refreezes each winter, and the permanently frozen soil beneath. 

Should the active layer increase in thickness due to warming, huge quantities of organic matter stored in the frozen soil would begin to thaw and decay, releasing large amounts of CO?  and methane into the atmosphere. 

Once this process begins, it will operate in a feedback loop known as the permafrost carbon feedback, which has the effect of increasing surface temperatures and thus accelerating the further warming of permafrost - a process that would be irreversible on human timescales. 

Arctic and alpine air temperatures are expected to increase at roughly twice the global rate, and climate projections indicate substantial loss of permafrost by 2100. A global temperature increase of 3°C means a 6°C increase in the Arctic, resulting in an irreversible loss of anywhere between 30 to 85 per cent of near-surface permafrost. 

Warming permafrost could emit 43 to 135 gigatonnes of carbon dioxide equivalent by 2100 and 246 to 415 gigatonnes by 2200. Emissions could start within the next few decades and continue for several centuries. 

Permafrost emissions could ultimately account for up to 39 per cent of total emissions, and the report's lead author warned that this must be factored in to the treaty to address global climate change expected to replace the Kyoto Protocol. 

"The release of carbon dioxide and methane from warming permafrost is irreversible: once the organic matter thaws and decays away, there is no way to put it back into the permafrost," said lead author Kevin Schaefer, from the University of Colorado's National Snow and Ice Data Center. 

"Anthropogenic emissions' targets in the climate change treaty need to account for these emissions or we risk overshooting the 2°C maximum warming target," he added. 

Most of the recent climate projections are biased on the low side relative to global temperature because the models do not at this time include the permafrost carbon feedback, the report says. Consequently, targets for anthropogenic greenhouse gas emissions based on these climate projections would be biased high.  

Ecosystems and Infrastructure under Threat

Warming permafrost also brings negative consequences in terms of ecosystem and infrastructure damage.

The dominant ecosystems in permafrost regions are boreal forests to the south and tundra to the north.  Permafrost is impermeable to water, so rain and melt water pool on the surface - forming innumerable lakes and wetlands which are used by migratory birds as summer breeding grounds. 

Ecosystem disturbances due to permafrost degradation will change species composition, and with it animal habitat and migration, according to the report. 

Longer growing seasons due to higher temperatures favour the growth of shrubs and woody vegetation resulting in a northward migration of the tree line. Permafrost degradation and the resultant drying of the land can also result in disturbances such as fires. Fire in boreal forests has recently increased in intensity and frequency, and could become more common in tundra regions. 

However, thawing permafrost is structurally weak, resulting in foundational settling that can damage or even destroy buildings, roads, pipelines, railways and power lines. Infrastructure failure can have dramatic environmental consequences, as seen in the 1994 breakdown of the pipeline to the Vozei oilfield in Northern Russia, which resulted in a spill of 160,000 tonnes of oil, the world's largest terrestrial oil spill. 

Roads, buildings and other infrastructure in discontinuous permafrost, which tends to be warmer, and along the Arctic coast, where salt content means small temperature changes can turn ice to ground water, are most vulnerable to damage. 

Climate change already could add up to US$6.1 billion to future costs for public infrastructure in the US state of Alaska between now and 2030, for example, and while there are only a handful of studies and reports evaluating the economic impacts of permafrost degradation, these indicate infrastructure maintenance and repair costs will increase. 

"Thawing permafrost represents a dramatic physical change with huge impacts to ecosystems and human infrastructure," said Mr. Schaefer. "Individual nations need to develop plans to evaluate the risks, costs, and mitigation strategies to protect human infrastructure in permafrost regions most vulnerable to thaw."


The report issues the following specific policy recommendations to address the potential economic, social and environmental impacts of permafrost degradation in a warming climate:

  • Commission a Special Report on Permafrost Emissions: The IPCC may consider preparing a special assessment report on how carbon dioxide and methane emissions from warming permafrost would influence global climate to support climate change policy discussions and treaty negotiations.
  • Create National Permafrost Monitoring Networks: To adequately monitor permafrost, individual countries may consider taking over operation of monitoring sites within their borders, increasing funding, standardizing the measurements and expanding coverage. This applies particularly to countries with the most permafrost: Russia, Canada, China and the United States. The International Permafrost Association should continue to coordinate development and the national networks should remain part of the Global Terrestrial Network for Permafrost.
  • Plan for Adaptation: Nations with substantial permafrost, such as those mentioned above, may consider evaluating the potential risks, damage and costs of permafrost degradation to critical infrastructure.  Most nations currently do not have such plans, which will help policy makers, national planners and scientists quantify costs and risks associated with permafrost degradation.

Additional information

The report was written by, and in collaboration with, the following partners:

  • Kevin Schaefer, University of Colorado, Boulder, USA;
  • Hugues Lantuit, Alfred Wegener Institute for Polar and Marine Research, Potsdam, Germany;
  • Vladimir E. Romanovsky, University of Alaska Fairbanks, Fairbanks, USA;
  • Edward A. G. Schuur, University of Florida, Gainesville, USA.

The full report can be downloaded here:

0 0

Printable Version  |  Link to this page


Comments 1 to 8:

  1. You wonder at times which rhubarb pot they have been hiding under. Sybil Fawlty springs to mind, Special Subject, the blindingly obvious. I suspect that damage to foundations will be the least of their worries. With anthropogenic CO2 emissions continuing their annual increase at the 3% level it should be time to remind those with the responsibility that under the laws of compound interest 3% annual equates to a doubling in 24 years. The start point was some few years ago now. Additionally a straight line projection forward for atmospheric CO2 ppm should give us 410 ppm in a Decade's time. Am I being unreasonable ? Johnb
    0 0
  2. I ran some quick calculations for you, Johnb. A straight line projection forward for atmospheric CO2 ppm gives 415 ppm in 2022 using the slope since 2000. That’s close enough to your estimate. A straight line projection to year 2100 gives 577 ppm, not doubled yet from today’s level (but it would be doubled from pre-industrial levels). The rate of increase is slightly exponential, not linear, so the proper number should be higher, maybe near 900 ppm in a worst case BAU scenario. The concentration of CO2 did increase by over 3 ppm last year (larger than any prior year in the record) but this increase represents only a 0.9% rise, not 3%. A 0.9% increase means a doubling time of 77 years. Most prior years increased 0.5% to 0.6%, therefore 0.9% might be anomalous and an overstatement of situation.
    0 0
  3. I'm quite surprised at this because until now I thought the permafrost thawing represented a much larger thread. If I read the above correctly the average yearly addition to the CO2 output will be about 1GT (43-135GT this century). Human output is currently around 30-35GT/y. So the 1GT/y seems like just a small addition. I must be missing something because a 39% of total emissions is mentioned.
    0 0
  4. It seems to defeat the purpose if a press release and report can only be accessed by a username and password. Or am I missing something?
    0 0
  5. Thanks Soundoff, I got my 3% figure for this past year from the following article in Scientific American. Other publications have also picked up on it. I believe that previous years have shown similar being in a rising trend from 2.6%. Always happy to be corrected. Johnb
    0 0
  6. Nicolas @ 3, it depends on which convention is being used for that 43-135Gt, Gt of CO2, or Gt of the C alone. If the latter then an extra 1Gt per year would be more than 10% as much C as human emissions, so not so small an addition. The convention used needs to be clarified.
    0 0
  7. Johnb and Soundoff, The Scientific American article said that the CO2 emissions increased 3% last year, not atmospheric concentration. There is not a direct one to one correspondence, since not all CO2 entering the atmospher is anthropogenic.
    0 0
  8. … as a truly "emerging issue" (the effects of warming permafrost) could not have been included in climate change modelling to date. Really? This issue has been “emerging” and largely ignored by overly conservative scientists for a decade or more. It is not as though the effects of thawing permafrost have only become apparent in the last year or so. We have known for decades that roads, railways, pipelines, bridges and buildings resting on permafrost foundations would be disastrously compromised by thawing which creates poorly drained waterlogged landscapes lacking bearing strength. That permafrost embodies or covers significant methane deposits, preventing their release into the atmosphere is hardly new. Their presence, estimated quantity and their warming effects, if released by thawing permafrost have been reported on in peer-reviewed Papers for at least 20 years. Over the last decade many scientists have reported their findings on cryogenic carbon, the threat posed my thawing permafrost and warned of the potential for this feedback to bring about abrupt climate change. The broader climate science community have largely ignored their findings. Belatedly declaring this a “truly emerging issue” seems a feeble excuse for the way it has been and continues to be ignored by those engaged in climate science modeling.
    0 0

You need to be logged in to post a comment. Login via the left margin or if you're new, register here.

The Consensus Project Website


(free to republish)

© Copyright 2024 John Cook
Home | Translations | About Us | Privacy | Contact Us