Expert assessment of vulnerability of permafrost carbon to climate change

• DOI: 10.1007/s10584-013-0730-7
• Publication Date: 2013-03-25T11:21:26Z
• Authors: E. A. G. Schuur; B. W. Abbott; W. B. Bowden; V. Brovkin; P. Camill; J. G. Canadell; J. P. Chanton; F. S. Chapin; T. R. Christensen; P. Ciais; B. T. Crosby; C. I. Czimczik; G. Grosse; J. Harden; D. J. Hayes; G. Hugelius; J. D. Jastrow; J. B. Jones; T. Kleinen; C. D. Koven; G. Krinner; P. Kuhry; D. M. Lawrence; A. D. McGuire; S. M. Natali; J. A. O’Donnell; C. L. Ping; W. J. Riley; A. Rinke; V. E. Romanovsky; A. B. K. Sannel; C. Schädel; K. Schaefer; J. Sky; Z. M. Subin; C. Tarnocai; M. R. Turetsky; M. P. Waldrop; K. M. Walter Anthony; K. P. Wickland; C. J. Wilson; S. A. Zimov
• Keywords: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmospheric Science; Global and Planetary Change; 550; Atmosphere; [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere; 551; 01 natural sciences; [SDU.ENVI] Sciences of the Universe [physics]/Continental interfaces, environment; Atmospheric Sciences; Climate Action; 13. Climate action; Earth Sciences; Meteorology & Atmospheric Sciences; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment; environment; Environmental Sciences; 0105 earth and related environmental sciences

Approximately 1700 Pg of soil carbon (C) are stored in the northern circumpolar permafrost zone, more than twice as much C than in the atmosphere. The overall amount, rate, and form of C released to the atmosphere in a warmer world will influence the strength of the permafrost C feedback to climate change. We used a survey to quantify variability in the perception of the vulnerability of permafrost C to climate change. Experts were asked to provide quantitative estimates of permafrost change in response to four scenarios of warming. For the highest warming scenario (RCP 8.5), experts hypothesized that C release from permafrost zone soils could be 19–45 Pg C by 2040, 162–288 Pg C by 2100, and 381–616 Pg C by 2300 in CO2 equivalent using 100-year CH4 global warming potential (GWP). These values become 50 % larger using 20-year CH4 GWP, with a third to a half of expected climate forcing coming from CH4 even though CH4 was only 2.3 % of the expected C release. Experts projected that two-thirds of this release could be avoided under the lowest warming scenario (RCP 2.6). These results highlight the potential risk from permafrost thaw and serve to frame a hypothesis about the magnitude of this feedback to climate change. However, the level of emissions proposed here are unlikely to overshadow the impact of fossil fuel burning, which will continue to be the main source of C emissions and climate forcing.