About a quarter of the land surface of the northern hemisphere of the earth is characterized by permanently frozen soils. Strong Arctic climate warming leads to thawing of permafrost soils, triggering large-scale landscape and ecosystems changes and thereby severely impacting the heat and water cycles of Arctic ecosystems. At the same time, carbon and other nutrients that are stored in large amounts in permafrost soils are exposed to microbial decomposition upon thaw. By this decomposition greenhouse gases are produced in the soils which can further amplify climate warming. In addition, thawing reduces the structural stability of the soils. The resulting erosion leads to strong mass wasting (movement of soil material) which can reshape entire landscapes.
These changes threaten the stability of Arctic ecosystems as well as the stability of infrastructures that are important to Arctic's life and economy. Infrastructures such as supply roads, airports, pipelines, and fuel storages are built directly on highly temperature-sensitive frozen ground. Offshore activities and shipping in the Arctic are also dependent on infrastructure such as ports in permafrost regions. The safety of this infrastructure is directly dependent on the thermal stability of the underlying and surrounding permafrost. Reliable and prompt assessments of risks of potential damages to both the ecology and infrastructure are therefore critically important.
The PermaRisk project aims to provide novel tools for the simulation of erosion and mass wasting processes in permafrost landscapes under a warming climate. Current land surface models used to simulate permafrost dynamics are not capable to represent soil erosion and mass wasting. Thus, current model assessments are most likely far too conservative in their estimates of permafrost thaw impacts. The following research questions have not yet been answered and are therefore at the focus of our project:
• How does climate warming affect the intensity of erosion and mass wasting processes?
• How does erosion and mass wasting affect infrastructure and ecosystem functions such as the energy, water, and nutrient cycles in the Arctic?
• What are the interactions between erosion-induced landscape changes and permafrost degradation?
In order to answer these crucial questions we will extend and improve the CryoGrid3 model developed by the Alfred Wegener Institute in cooperation with the University of Oslo. We will use field measurements as well as satellite data from three key research sites in Alaska, Canada, and Siberia for model validation. Gaining detailed insights into erosion and mass wasting processes at the research sites will help to mitigate future damage to buildings, roads, and other infrastructure. Furthermore, we aim to provide a novel tool for mapping risks in permafrost environments that are yet impossible to quantify. Finally, we hope to gain new insights into the sensitivity of the Arctic to climatic change and potential feedback mechanisms.