Importance of soil thermal regime in terrestrial ecosystem carbon dynamics in the circumpolar north
O'Donnell, Jonathan A.
Kicklighter, David W.
Sokolov, Andrei P.
Melillo, Jerry M.
MetadataShow full item record
In the circumpolar north (45-90°N), permafrost plays an important role in vegetation and carbon (C) dynamics. Permafrost thawing has been accelerated by the warming climate and exerts a positive feedback to climate through increasing soil C release to the atmosphere. To evaluate the influence of permafrost on C dynamics, changes in soil temperature profiles should be considered in global C models. This study incorporates a sophisticated soil thermal model (STM) into a dynamic global vegetation model (LPJ-DGVM) to improve simulations of changes in soil temperature profiles from the ground surface to 3 m depth, and its impacts on C pools and fluxes during the 20th and 21st centuries.With cooler simulated soil temperatures during the summer, LPJ-STM estimates ~0.4 Pg C yr-1 lower present-day heterotrophic respiration but ~0.5 Pg C yr-1 higher net primary production than the original LPJ model resulting in an additional 0.8 to 1.0 Pg C yr-1 being sequestered in circumpolar ecosystems. Under a suite of projected warming scenarios, we show that the increasing active layer thickness results in the mobilization of permafrost C, which contributes to a more rapid increase in heterotrophic respiration in LPJ-STM compared to the stand-alone LPJ model. Except under the extreme warming conditions, increases in plant production due to warming and rising CO2, overwhelm the enhanced ecosystem respiration so that both boreal forest and arctic tundra ecosystems remain a net C sink over the 21st century. This study highlights the importance of considering changes in the soil thermal regime when quantifying the C budget in the circumpolar north.
© The Author(s), 2016. This is the author's version of the work and is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Global and Planetary Change 142 (2016): 28-40, doi:10.1016/j.gloplacha.2016.04.011.
The following license files are associated with this item:
Except where otherwise noted, this item's license is described as Attribution-NonCommercial-NoDerivs 3.0 United States
Showing items related by title, author, creator and subject.
Importance of recent shifts in soil thermal dynamics on growing season length, productivity, and carbon sequestration in terrestrial high-latitude ecosystems Euskirchen, E. S.; McGuire, A. David; Kicklighter, David W.; Zhuang, Qianlai; Clein, Joy S.; Dargaville, R. J.; Dye, D. G.; Kimball, John S.; McDonald, Kyle C.; Melillo, Jerry M.; Romanovsky, V. E.; Smith, N. V. (2005-10-07)In terrestrial high-latitude regions, observations indicate recent changes in snow cover, permafrost, and soil freeze-thaw transitions due to climate change. These modifications may result in temporal shifts in the growing ...
Simultaneous determination of thermal conductivity, thermal diffusivity and specific heat in sI methane hydrate Waite, William F.; Stern, Laura A.; Kirby, S. H.; Winters, William J.; Mason, D. H. (Blackwell Publishing, 2007-03-11)Thermal conductivity, thermal diffusivity and specific heat of sI methane hydrate were measured as functions of temperature and pressure using a needle probe technique. The temperature dependence was measured between −20°C ...
Tierney, Jessica E.; Oppo, Delia W.; Rosenthal, Yair; Russell, James M.; Linsley, Braddock K. (American Geophysical Union, 2010-03-05)Instrumental data suggest that major shifts in tropical Pacific atmospheric dynamics and hydrology have occurred within the past century, potentially in response to anthropogenic warming. To better understand these trends, ...