Almost 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 infrastructure that is important to Arctic's life and economy. Infrastructure such as supply roads, ports, pipelines, airports and fuel storages is often built directly on highly temperature-sensitive frozen ground. 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 founded by the Federal Ministry of Education and Research (BMBF):
• 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 permafrost model CryoGrid3 developed by the Alfred Wegener Institute in cooperation with the University of Oslo. To ensure realistic model development, we will use field measurements as well as satellite data from three key research sites in Alaska, Canada, and Siberia for model validation.
Contributions to the management of climatic change and the sustainable development of the Arctic
The improved permafrost model will provide deeper insights into the erosion and mass wasting processes at the study sites. Based on these insights, future risks can be assessed more precisely and sound strategies for the prevention of damage to infrastructure in the Arctic can be developed. This will help to mitigate the negative impact of rapid climate warming on the local population and the economy in the Arctic.
The long-term goal of our project is to enhance regional and global climate simulations in order to improve risk assessments of permafrost degradation under different climate warming scenarios. Detailed analyzes of changes in the energy, water and nutrient cycles help us to better understand the climate sensitivity of the Arctic ecosystems and allow the development of sustainable conservation measures.