USGS Geological Research Activities with the U.S. Bureau of Land Management

Environmental Impacts of Climate Variability

Monitoring, Modeling, and Forecasting Ecosystem and Climate Change

The USGS plays a critical role in global environmental change research by providing field-based data and information to calibrate and test regional and global ecosystem models. This area of research is a high priority of the US Global Change Research Program and represents an effort to develop research and products that will be useful to the global change research community, and decision making by land and resource managers on the potential impacts of likely future changes of the Earth climate system.

Alaska Climate Monitoring

One of the Earth Surface Dynamics Program research efforts is Arctic-Alaska climate monitoring, which is being conducted in close collaboration with the BLM (which has provided helicopter support in the past) and the U.S. Fish & Wildlife Service. The Global Terrestrial Network-Permafrost (GTN-P) is part of the Global Climate Observing System (GCOS), which was established in 1992 to ensure that the observations and information needed to address worldwide climate related issues are obtained. GCOS is intended to be a long-term operational system capable of providing the comprehensive observations required for monitoring the climate system, for detecting and attributing climate change, for assessing the impacts of climate variability and change, and for supporting research toward improved understanding of the climate system. The GCOS steering committee approved the development of a globally comprehensive permafrost monitoring network (GTN-P) in 1999 to detect temporal changes in the solid earth component of the cryosphere (i.e., permafrost). Changes in permafrost temperature and active layer thickness frequently reflect changes in surface climate over time, and therefore serve as useful indicators of climate change. The GTN-P network is a long-term international effort involving 12 nations and has two primary observational components: the active layer (i.e., the surface layer that freezes and thaws annually in cold regions) and the thermal state of the underlying permafrost.

Active layer monitoring

In the U.S., the National Science Foundation and the Department of the Interior jointly fund the GTN-P. All of the GTN-P observational sites (30) for active layer monitoring are located in Alaska. The DOI currently maintains 9 of these active-layer monitoring stations, most of which were installed in 1998. The network provides broad spatial coverage across Arctic Alaska with sites located in the National Petroleum Reserve Alaska (NPRA) and the Arctic National Wildlife Refuge (ANWR). These fully automated stations continuously monitor:

• Air temperature
• Snow Depth
• Solar radiation
• Shallow permafrost temperature (at several depths)

The DOI stations are co-located with a deep borehole, forming a Permafrost Climate-Detection Observatory. The data from these stations are essential for:

• Detecting contemporary climate changes in the Arctic
• Documenting the sensitivity of permafrost to climate change
• Providing data critical for testing climate models and cryosphere models
• Improving the reliability of impact assessments based on these models

Permafrost Thermal State

DOI also maintains an array of 21 deep boreholes (>125 m) in the NPRA for monitoring the thermal state of permafrost. Analysis of temperatures from the deep boreholes provided some of the first evidence that the Alaskan Arctic had warmed 2-4 degrees Celsius during the 20th century prior to the mid-1980's (Lachenbruch and Marshall, Science, 1986). DOI's 21 deep boreholes array is the largest array of deep boreholes in the world available for monitoring the thermal state of permafrost. Temperature measurements in this array are important for determining the long-term terrestrial response to climate change in the Arctic.

Carbon in Alaska

Alaska, for the past 30 years, has been undergoing a warming trend. This change in climate is being observed in glacier retreat, sea surface ice, melting, and degradation of permafrost at the southern boundary in the boreal forest, and CO2 emissions from Arctic ecosystems. Enormous amount of carbon exists in the ecosystems and in soils below the permafrost in Alaska. These reserves could be released as CO2 through enhanced fires and decomposition. Discontinuous permafrost is characteristic of this region where large fires result in permafrost degradation and oxidation of organic-rich layers, followed by vegetative regrowth and refreezing. The interaction of large wildfires, permafrost degradation, decomposition and forest regrowth are the main focus of our sampling and modeling strategies. The USGS scientists in partnership with the BLM, Army, and U.S. Forest Service are investigating:

• Fire impacts on heavy metal chemistry
• Atmospheric emissions from fire
• Fire effects on soil nutrients
• Fire and the carbon balance of boreal ecosystems

As fires cause permafrost to melt, the fate of the carbon is uncertain: carbon release to the atmosphere could increase atmospheric CO2; or carbon uptake by re-growth of plants could offset the rise in CO2. It is certain, however, that climate sensitivity and impact on CO2 in the boreal and arctic systems are significant and that moose and fish, along with human, habitats are changing in response to fire, climate change, and permafrost responses.