The polar regions are thought to be among the most vulnerable ecosystems impacted by rapid and long-term changes in climate (IPCC, 2007). Satellite and ground surface measurements have shown that in recent decades, the polar regions have experienced more rapid changes in the seasonality and areal extent of snow cover and of sea ice than in the past. In the Arctic, the summer of 2007 marked the first recorded year that a navigable Northwest Passage opened in the Arctic Ocean since the Canadian Ice Service began routine navigation monitoring in 1972. NASA’s Earth Observatory map and graph show the minimum extent of sea ice in the Arctic.
This potential shortcut for international shipping raises issues of sovereignty and increasing environmental impacts. At the south pole in recent years, several ice shelves have detached suddenly and catastrophically from the Antarctic polar ice mass region. These changes at the poles have significant effects on the ecosystem food chain, disrupting traditional locations of feeding and breeding grounds for wildlife, challenging the safety of Arctic hunters as ice conditions shift, and latitudinally displacing various fish and sea mammal populations.
As the extent of sea ice changes during polar summers and winters, what is happening to the land surface and soils in the Arctic polar regions and on Antarctica? In contrast to more temperate regions, soils and sediments at depth are permanently frozen and remain frozen even during the warmest seasons of the year in polar regions. This permanently frozen portion of the soil is called ‘permafrost.’ Immediately above the permafrost may be a transitional zone separating the permafrost from the active layer that extends to the land surface. The ‘active layer’ is a dynamic soil layer, seasonally freezing and thawing, thus its name. It is important to understand the relation between the permafrost and active layers because a continual long-term decrease in permafrost thickness with consequent increase in active layer thickness is thought to be an indicator of long-term warming. In part, these dynamic conditions cause soils in polar regions and in high altitude areas to be particularly sensitive to climate change. Little is known about long-term soil climate in regions of permafrost, but NRCS has significant expertise in monitoring soil climate in regions of extremes.
As early as 1995, some soil climate stations were established under the auspices of the US Global Climate Change Program to better understand soil moisture and temperature regimes for soil taxonomic classification in extremely cold regions. Additional sites have been added in the last several years. The installation of multi-depth sensors provides a comparative record of permafrost and active layer soil moisture and temperature at multiple depths.
Relatively little is known about Antarctic soils and soil-climate in particular, other than that the soils may represent the coldest, driest part of the soil-climate continuum. Nine long-term soil-climate stations are located in the Ross Island Region of Antarctica such that the effects of latitude, elevation, and soil age could be studied. Three study sites were initially chosen to conduct research on the effects of fuel spills on Antarctic soils. All stations are part of an international cooperative project led by Landcare Research, Hamilton, New Zealand and supported by Antarctica New Zealand in Christchurch. At all stations, measurements at multiple depths are made at regular intervals throughout the day and recorded every hour. Because of the remoteness and extreme conditions at many of the locations, data cannot be transmitted instantaneously but is manually downloaded once a year from each station. A complete map of the sites, station records, data labels, and soils descriptions can be downloaded at the Soil Climate Research Stations section of the NRCS National Soil Survey website. You can also refer to the article, "Soil Climate Monitoring Project in the Ross Island Region of Antarctica," to learn more about the project.
Beginning in 1995, soil climate monitoring stations were established on the North Slope of Alaska. Several southern Alaskan sites were also established at this time. Most of the North Slope sites were established as part of the USDA Global Climate Change research program. Effects of global change can be detected in the seasonal thaw characteristics and active-layer depths of permafrost soils. Long-term changes in the active layer thickness and duration have impacts on soil processes such as storage of soil organic carbon and near-surface hydrology. This research is conducted cooperatively with the University of Delaware, the University of Montana Missoula, and the University of Alaska Fairbanks. The university research is funded through the National Science Foundation (NSF) research grants. Yearly service and data collection visits are required to repair and maintain the stations. Data are recorded every hour. At present, only data and metadata for the North Slope sites can be accessed and downloaded through NRCS National Soil Survey website (at the Soil Climate Research Station section). Data from the Soil Climate Analysis Network (SCAN) stations at the southern part of Alaska can be accessed and downloaded from the Alaska SCAN section of the National Water and Climate Center website.
2nd from the Bottom Image: Photo courtesy of the U.S. Fish and Wildlife Service
Other Images: Photos courtesy of the NRCS National Soil Survey Center