Skip to main content
U.S. flag

An official website of the United States government

The State of the Art of Modeling Permafrost Carbon Dynamics

Presentation Date
Thursday, December 12, 2024 at 1:40pm - Thursday, December 12, 2024 at 5:30pm
Location
Convention Center - Hall B-C (Poster Hall)
Authors

Author

Abstract

The potential for a release of a large amount of carbon from permafrost thaw, relative to total-predicted-future-global-natural emissions, and the high inter-model variability in the future carbon budget of permafrost soils (McGuire et al, 2016; Steinert et al., 2024; McGuire, 2018), suggests that more modeling work is needed to reduce this variability. Our overarching questions are what is the state of the art of modeling permafrost carbon dynamics, and where, specifically, should efforts be focused? We assessed the state of the art of modeling permafrost thaw and ensuing emissions in the land component of Earth System Models (ESMs) and standalone land / land surface / terrestrial biosphere models. To do so, we surveyed individual modelers’ perception of the level of completeness of their models, in their ability to represent below-ground carbon dynamics. We limited the scope of this study to below-ground processes only, to keep it realistic logistically, and because models are missing many of the processes needed to model permafrost carbon, permafrost carbon thaw, and the positive carbon-climate feedback. Of the 41 land modeling groups contacted across the globe, many of which are affiliated to an ESM, with a request to participate in our survey, 36 completed the survey (88% response rate). Our survey included processes related to modeling the dynamics of soil energy, soil water, soil carbon, snow, nutrients, vegetation (a few processes only), disturbances and numerics. Of the 174 total “checks” a team could obtain, which represent inclusion of the different processes necessary to represent permafrost thaw (1 check/process), all sections combined, the mean score was 49%, without including checks given to processes which survey participants indicated as “under active development”. The standard deviation across the mean was 16%. Our results show that disturbances are not sufficiently developed, and development is still needed in the soil energy, soil water, soil carbon and snow model sections across most models. Overall, the state of the art of modeling permafrost thaw and ensuing emissions in these models is incomplete, and shows a wide spread across models, which likely explains in part the large inter-model variability in CMIP6 model results for net ecosystem exchange in the arctic boreal zone.

Category
Biogeosciences
Funding Program Area(s)