Physical Science Component
In phase III of Alaska EPSCoR, the science components are integrated into one program addressing social-ecological systems in Alaska. Here the physical science component is described.

Climate change in Alaska and the circumpolar North is having a major impact on permafrost with important implications for both engineering and ecology. Traditionally, methods of engineering design in permafrost regions were concentrated on the interaction between structures and permafrost. The main design approach for the permafrost region has been to maintain the frozen state of the soil and its pre-construction thermal regime. The design is based on the assumption that permafrost in the area surrounding structures remains unchanged; however, climate change now is making this approach unsafe even in the continuous permafrost zone. In the discontinuous permafrost zone, such an approach always has been misleading.

The combined impact of climate change and development on permafrost has created new challenges for engineers designing structures for use in areas with degrading permafrost. There are no proven design approaches for building on degrading permafrost, and many structures in Alaska have suffered excessive settlement due to continuing permafrost degradation. In our program we explicitly address the engineering design approaches that must be incorporated in building on permafrost and apply this information to improve understanding of climate-permafrost interrelationships under the more complex conditions of natural ecosystems.

The same physical principles used to improve engineering designs on permafrost apply to natural ecosystems and their protective effects on permafrost. The formation, existence, and stability of permafrost in the discontinuous zone therefore depend not only on cold climatic conditions, but also on ecosystem components, especially vegetation. The ways in which climate and vegetation interact to influence permafrost, however, are not well understood. For example, permafrost temperature in undisturbed tundra has increased more rapidly than air temperature in the past twenty years, which cannot be explained by a simple climate-permafrost linkage. We introduce a new conceptual framework to study interactions among permafrost, climate change, vegetation, wildfire, and society. Direct climate impacts on permafrost are relatively well studied and can be predicted by models developed by climate and permafrost scientists. Indirect effects, such as the influence of changing fire regimes on vegetation-mediated permafrost development, however, are poorly understood and require cooperation between physical and biological scientists. We hypothesize that climate directly determines permafrost formation and stability in the continuous permafrost zone but that climate-vegetation-permafrost interactions are essential to permafrost response to climate change in the discontinuous permafrost zone. Studies of climate-ecosystem-permafrost interaction in these two permafrost zones will help elucidate permafrost reaction to climate change.