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.
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. PETA-CARB aims at quantifying the amount, distribution, and vulnerability of deep permafrost soil organic carbon pools, as well as how rapidly permafrost thaw impacts these carbon pools on various spatial and temporal scales, allowing projection of future interactions between the permafrost carbon pools and Earth’s climate.
The project combines 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 are:
(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.
We focus 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 will involve synthesis of data from other research projects and study sites that allow upscaling of results to regional to continental scales.
The PETA-CARB project (2013-2018) is funded with a Starting Grant by the European Research Council (ERC) and is 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, serves as host institution and provides scientific infrastructure, logistics, and administrative support.