With climate warming predicted to continue during the next century, amplified in Arctic and sub-Arctic regions (ACIA 2005), thermokarst activity will generally spread and intensify still more. Thawing of permafrost is projected to be concen trated in the current discontinuous permafrost zone during the next 100 years (Deslile 2007). This is of particular concern in sub-Arctic Alaska, where ~40% of the area may be susceptible to thermokarst (Jorgensen et al. 2007). Thus, global warming at high latitudes is putting large areas of ice-rich permafrost at risk of thermokarst subsidence and related disturbances (Nelson et al. 2001).
Although projected climate warming in the twenty-first century will lead to deeper ground thaw in many permafrost regions, its impacts will be modulated by site-specific conditions. For example, peat and vegetation cover may buffer permafrost from severe degradation, whereas local disturbance of ground cover or fires in the boreal forest or tundra may accelerate permafrost thaw (Yi et al. 2007). Thus, caution is needed in generalizing between projected changes in atmospheric climate and geocryological responses.
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