Title |
A simplified, data-constrained approach to estimate the permafrost carbonclimate feedback
|
---|---|
Published in |
Philosophical Transactions of the Royal Society A: Mathematical, Physical & Engineering Sciences, November 2015
|
DOI | 10.1098/rsta.2014.0423 |
Pubmed ID | |
Authors |
C D Koven, E A G Schuur, C Schädel, T J Bohn, E J Burke, G Chen, X Chen, P Ciais, G Grosse, J W Harden, D J Hayes, G Hugelius, E E Jafarov, G Krinner, P Kuhry, D M Lawrence, A H MacDougall, S S Marchenko, A D McGuire, S M Natali, D J Nicolsky, D Olefeldt, S Peng, V E Romanovsky, K M Schaefer, J Strauss, C C Treat, M Turetsky |
Abstract |
We present an approach to estimate the feedback from large-scale thawing of permafrost soils using a simplified, data-constrained model that combines three elements: soil carbon (C) maps and profiles to identify the distribution and type of C in permafrost soils; incubation experiments to quantify the rates of C lost after thaw; and models of soil thermal dynamics in response to climate warming. We call the approach the Permafrost Carbon Network Incubation-Panarctic Thermal scaling approach (PInc-PanTher). The approach assumes that C stocks do not decompose at all when frozen, but once thawed follow set decomposition trajectories as a function of soil temperature. The trajectories are determined according to a three-pool decomposition model fitted to incubation data using parameters specific to soil horizon types. We calculate litterfall C inputs required to maintain steady-state C balance for the current climate, and hold those inputs constant. Soil temperatures are taken from the soil thermal modules of ecosystem model simulations forced by a common set of future climate change anomalies under two warming scenarios over the period 2010 to 2100. Under a medium warming scenario (RCP4.5), the approach projects permafrost soil C losses of 12.2-33.4 Pg C; under a high warming scenario (RCP8.5), the approach projects C losses of 27.9-112.6 Pg C. Projected C losses are roughly linearly proportional to global temperature changes across the two scenarios. These results indicate a global sensitivity of frozen soil C to climate change (γ sensitivity) of -14 to -19 Pg C °C(-1) on a 100 year time scale. For CH4 emissions, our approach assumes a fixed saturated area and that increases in CH4 emissions are related to increased heterotrophic respiration in anoxic soil, yielding CH4 emission increases of 7% and 35% for the RCP4.5 and RCP8.5 scenarios, respectively, which add an additional greenhouse gas forcing of approximately 10-18%. The simplified approach presented here neglects many important processes that may amplify or mitigate C release from permafrost soils, but serves as a data-constrained estimate on the forced, large-scale permafrost C response to warming. |
X Demographics
Geographical breakdown
Country | Count | As % |
---|---|---|
Netherlands | 1 | 17% |
United States | 1 | 17% |
Germany | 1 | 17% |
Unknown | 3 | 50% |
Demographic breakdown
Type | Count | As % |
---|---|---|
Members of the public | 5 | 83% |
Scientists | 1 | 17% |
Mendeley readers
Geographical breakdown
Country | Count | As % |
---|---|---|
United States | 4 | 1% |
United Kingdom | 1 | <1% |
Australia | 1 | <1% |
Unknown | 340 | 98% |
Demographic breakdown
Readers by professional status | Count | As % |
---|---|---|
Student > Ph. D. Student | 69 | 20% |
Researcher | 64 | 18% |
Student > Master | 37 | 11% |
Student > Bachelor | 33 | 10% |
Professor | 18 | 5% |
Other | 50 | 14% |
Unknown | 75 | 22% |
Readers by discipline | Count | As % |
---|---|---|
Environmental Science | 92 | 27% |
Earth and Planetary Sciences | 87 | 25% |
Agricultural and Biological Sciences | 29 | 8% |
Biochemistry, Genetics and Molecular Biology | 7 | 2% |
Social Sciences | 6 | 2% |
Other | 31 | 9% |
Unknown | 94 | 27% |