The Challenge
Arctic permafrost deposits are estimated to freeze-lock as much carbon in the atmosphere, allowing a potentially significant climate warming feedback loop when permafrost thaws and carbon is released as greenhouse gases. However, permafrost carbon pool estimates have high uncertainties and the dynamics of rapid permafrost thaw in a warming Arctic are poorly understood. None of these pools or rapid processes are considered in current Earth System Models so far.
Project Objectives and Results
Data on the spatial distribution of soil carbon pools and their vulnerability to rapid thaw processes such as thermokarst is required to determine what, and how fast, climate feedbacks might result. The PETA-CARB project therefore aimed at quantifying the amount, distribution and vulnerability of deep carbon stores in permafrost deposits. It was also investigated how fast dew processes influence permafrost carbon storage on different temporal and spatial scales. The overall goal of the project was to improve the prediction of future interactions between permafrost carbon storage and the Earth's climate.
Methodology
The project combined remote sensing based change detection, mapping, and spatial data analysis for permafrost landscapes, quantitative field studies, and modelling of thermokarst processes to quantify the size and vulnerability of deep permafrost soil carbon pools to rapid thaw and resulting impacts. The three research topics were:
(1) Systematic measurement of rapid permafrost thaw,
(2) Characterization of deep permafrost SOC stocks and carbon accumulation rates, and
(3) Quantification of deep permafrost SOC pools and vulnerability assessment.
Study Regions
We focused our field expeditions on different regions in Alaska (Arctic Coastal Plain, Yukon Kuskokwim-Delta) and Siberia (Lena Delta, Central Yakutia) that represent a variety of permafrost and environmental conditions. However, the scope of our project goes beyond these core study sites and is involving synthesis of data from other research projects and study sites that allow upscaling of results to regional to continental scales.
Funding
The PETA-CARB project (2013-2018) was funded with a Starting Grant by the European Research Council (ERC) and was additionally supported by the Helmholtz Association with special funds for successful ERC grants. The Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, in particular the Periglacial Research Unit in Potsdam, served as host institution and provides scientific infrastructure, logistics, and administrative support.
