AGU: Geophysical Research Letters

 

Editors' Highlight

Abrupt increase in permafrost degradation in Arctic Alaska

Permafrost in Arctic zones has typically been considered stable because of low mean annual temperatures. However, the risk for thaw subsidence in Arctic lowlands is high because of large volumes of ground ice at the top of the permafrost, which can melt in response to changes in the surface energy balance. To analyze the stability of Arctic permafrost, Jorgenson et al. (2006) studied ground ice wedges in northern Alaska using field surveys conducted in 2003 and 2004, aerial photographs taken in 2001, and spectral analysis of these aerial photographs. By comparing these data to aerial photographs taken in 1982 and 1945, the authors identified temporal changes in various stages of ground ice within their field study and found that an abrupt, large increase in permafrost degradation occurred in northern Alaska since 1982 to areas that had previously been stable for thousands of years. The authors inferred that this degradation was associated with record high temperatures observed in the area between 1989 and 1998, suggesting that even modest global warming can have detrimental effects on permafrost.

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