PAGES 229–236 Arctic Landscapes in Transition: Responses to Thawing Permafrost

• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2010
• Subjects: Arctic; Arctic Ocean; Climate change; Ice; permafrost; Tundra; wedge*
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.232.887; http://thermokarst.psu.edu/2010_Eos_Arctic_Transitions.pdf

Observations indicate that over the past several decades, geomorphic processes in the Arctic have been changing or intensifying. Coastal erosion, which currently supplies most of the sediment and carbon to the Arctic Ocean [Rachold et al., 2000], may have doubled since 1955 [Mars and Houseknecht, 2007]. Further inland, expansion of channel networks [Toniolo et al., 2009] and increased river bank erosion [Costard et al., 2007] have been attributed to warming. Lakes, ponds, and wetlands appear to be more dynamic, growing in some areas, shrinking in others, and changing distribution across lowland regions [e.g., Smith et al., 2005]. On the Arctic coastal plain, recent degradation of frozen ground previously stable for thousands of years suggests 10–30 % of lowland and tundra landscapes may be affected by even modest warming [Jorgenson et al., 2006]. In headwater regions, hillslope soil erosion and landslides are increasing [e.g., Gooseff et al., 2009]. These changes result from a system- wide response to changing climate [Hinzman et al., 2005] arising from a region- wide warming and thawing of permafrost (Figure 1). Permafrost is ground that has existed at temperatures below freezing for at least 2 years. Within permafrost lie all forms of ground ice (ice in pores, cavities, and voids, or other openings in soil or rock) as well as massive ice (ice formed as lenses, layers, wedges, and blocky structures). Massive ice leaves large unstable voids in soils when it melts. Although some level of landscape change is expected in response to natural climate variability, the scale and rapidity of recently observed changes suggest that Arctic landscapes may be particularly sensitive to climate change and capable of rapid geomorphic responses to perturbations. Scientists