Publication Date:
2014-07-10
Description:
A large amount of organic carbon stored in permafrost soils across the high latitudes is
vulnerable to thaw, decomposition and release to the atmosphere as a result of climate
warming. This process is anticipated to be a significant positive feedback on future radiative
forcing from terrestrial ecosystems to the Earth’s climate system. Here, we describe the
development of a geospatial framework designed to characterize permafrost carbon
vulnerability in the northern hemisphere. The broadly-defined regional classification is based
on a Pan-Arctic spatial representation of the major environmental controls on a) the rate and
extent of permafrost degradation and thaw, b) the quantity and quality of soil organic matter
stocks, and c) the form of permafrost carbon emissions as CO2 and CH4. The framework was
developed by integrating existing spatial data layers describing permafrost and ground ice
conditions, bioclimatic zones, and topographic and geographic attributes. The resulting
Permafrost Regionalization Map (PeRM) can be used for synthesis studies on permafrost
carbon vulnerability, including data representativeness and gap analysis, model-data
integration and model benchmarking.
The utility of the PeRM framework is demonstrated here through areal density analysis
and spatial summaries of existing data collections describing the fundamental components of
permafrost carbon vulnerability. We use this framework to describe the spatial
representativeness and variability in measurements within and across PeRM regions using
observational data sets describing active layer thickness, soil pedons and carbon storage, longterm
incubations for carbon turnover rates, and site-level monitoring of CO2 and CH4 fluxes
from arctic tundra and boreal forest ecosystems. We then use these regional summaries of the
observational data to benchmark the results of a process-based biogeochemical model for its
skill in representing the magnitudes and spatial variability in these key indicators. Finally, we
are using this framework as a basis for higher-resolution mapping of key regions of particular
vulnerability to both press (active layer thickening) and pulse (thermokarst development)
disturbances, which is guiding on-going research toward characterizing permafrost
degradation and associated vegetation changes through multi-scale remote sensing. Overall,
this work provides a critical bridge between the abundant but disordered observational and
experimental data collections and the development of higher-complexity process
representation of the permafrost carbon feedback in geospatial modeling frameworks.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Conference
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notRev