Climate change in interior Alaska is affecting permafrost freeze and thaw processes, wetland dynamics, phenology and distribution patterns of species, precipitation patterns, and fire frequency and intensity. These impacts are occurring in the midst of already altered hydrologic and fire regimes resulting from changes in land use on and off military installations, military training activities, and the presence of invasive species. The potential ecosystem responses to climate change and to these non-climatic anthropogenic stressors could have severe ramifications on how, where, and when the Department of Defense (DoD) can train in Alaska.
Permafrost is soil, sediment, and rock that stays at or below the freezing point of water for two or more years, though ice is not always present. Permafrost can be either continuous or discontinuous and when present is covered by a thin active layer that seasonally thaws during the summer. Climate change can degrade permafrost by affecting its extent and the degree of seasonal thawing
To address these concerns, SERDP initiated a suite of projects in FY 2011 focused on understanding and predicting how permafrost changes will impact ecological systems and the implications for Alaskan training land sustainability. These efforts will fill knowledge gaps relative to how climate change is affecting permafrost and the overall system dynamics, informing decisions on the development of future training and installation management plans.
Permafrost degradation in many areas of Alaska has the potential to dramatically affect surface features such as soil and vegetation, as well as surface and subsurface hydrology. At the same time, changes in soil, vegetation, and fire regime can impact the rates and extent of permafrost degradation. Understanding the connections among these phenomena is critical for exploring and testing the response of permafrost to climate change. Under the SERDP project Identifying Indicators of State Change and Forecasting Future Vulnerability in Alaskan Boreal Ecosystems (RC-2109), Dr. Edward Shuur from the University of Florida and his team will determine the mechanistic links among fire, soils, permafrost, and vegetation succession to develop and test field-based ecosystem indicators that can be used to predict boreal ecosystem vulnerability and forecast landscape change in response to projected changes in climate and fire regime and management. The resulting maps will help land managers identify those DoD lands that are resistant and those that are vulnerable to permafrost degradation.
Modeling surface hydrology is complicated when permafrost is present. Under the SERDP project Addressing the Impacts of Climate Change on U.S. Army Alaska with Decision Support Tools Developed through Field Work and Modeling (RC-2110), Dr. Thomas Douglas of the U.S. Army Cold Regions Research and Engineering Laboratory (CRREL) and his team will couple a widely used physical-based hydrology model with a permafrost thermal model. Coupling of these models will expand capabilities for modeling permafrost hydrology in cold regions and enable better prediction of how these unique ecosystems will respond to climate change. The team will use climate projections for the next 100 years to model ecosystem changes in interior Alaska. The end result will be a GIS-based decision support system using spatially explicit ecosystem response data on climate and non-climate related anthropogenic stressors.
Permafrost’s reach extends even further than surface hydrology and features. Its distribution in interior Alaska is the primary influence governing groundwater flow, recharge, and discharge and hence ecosystem state, landscape evolution, and infrastructure sustainability. Characterizing permafrost distribution and developing tools to predict evolving groundwater and permafrost interaction and ecosystem changes driven by climate change would provide a framework to understand the current hydrologic state and to predict hydrologic changes across Alaska. Under the SERDP project Improved Understanding of Permafrost Controls on Hydrology in Interior Alaska by Integration of Ground-Based Geophysical Permafrost Characterization and Numerical Modeling (RC-2111) led by Dr. Michelle Walvoord of the U.S. Geological Survey, three-dimensional numerical modeling tools are being developed based on field experimental data to enable prediction of groundwater flow and interaction with permafrost, future hydrologic changes, and ecosystem consequences associated with different climate change scenarios. In addition, this project will further the development of tools for delineating the extent and depth of permafrost under different environmental conditions.
- SERDP and ESTCP Resource Conservation and Climate Change Program Area
- Identifying Indicators of State Change and Forecasting Future Vulnerability in Alaskan Boreal Ecosystems
- Addressing the Impacts of Climate Change on U.S. Army Alaska with Decision Support Tools Developed through Field Work and Modeling
- Improved Understanding of Permafrost Controls on Hydrology in Interior Alaska by Integration of Ground-Based Geophysical Permafrost Characterization and Numerical Modeling