Thawing Permafrost Expected To Cause Additional Warming

Permafrost covering almost a quarter of the northern hemisphere contains enormous amounts of carbon, maybe more 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 alter ecosystems and cause costly infrastructural damage due to increasingly unstable ground, the report says.

Policy Implications of Warming Permafrost seeks to highlight the potential hazards of carbon dioxide and methane emissions from warming permafrost, which will not be included in climate-prediction modelling done for the fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC).

The report recommends a special IPCC study 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.

Most of the current permafrost formed during or since the last ice age and extends to  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 CO₂  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.

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

Recommendations

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. 

·        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.

(UNEP)

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.