Climatic Change http://doi.org/k5q (2013)

The northern permafrost zone contains enormous stores of carbon (∼1,700 Pg). Consequently the amount, rate and form of carbon release to the atmosphere from thawing permafrost all have the potential to significantly influence the future magnitude of climate change. The extent of this effect remains highly uncertain, however, because permafrost carbon dynamics are poorly represented in models that are used to assess atmosphere–biosphere carbon exchange.

In lieu of the quantitative information required to improve these models, expert judgments about future carbon emissions from permafrost can help to outline the potential risks posed by permafrost thaw and frame future research questions. Edward Schuur, from the University of Florida, and co-workers undertook a survey to quantify variability in experts' perception of the vulnerability of permafrost carbon to climate change. Respondents provided quantitative estimates of permafrost change in response to a number of warming scenarios corresponding to particular greenhouse gas representative concentration pathways (RCPs).

Results indicate that in response to a high RCP (8.5), carbon release from permafrost soils could be 162–288 Pg C in CO2 equivalent by 2100, and up to 50% larger, depending on how the global warming potential of methane is calculated. Two thirds of this release was believed to be avoidable under the lowest warming scenario (RCP 2.6). Importantly, the levels of emissions proposed are unlikely to overshadow fossil-fuel sources.