Recent Increases in Permafrost Thaw Rates and Areal Loss of Palsas in the Western Northwest Territories, Canada

Steven D. Mamet*, Kwok Pan CHUN, Geoffrey G.L. Kershaw, Michael M. Loranty, G. Peter Kershaw

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

Decay of palsas can indicate permafrost status, particularly in regions where air temperatures have increased rapidly in recent decades. Using weather data, annual surveys of active-layer thickness, and analyses of high-resolution aerial imagery from the eastern Selwyn/western Mackenzie Mountains, NT, Canada, we show that permafrost temperatures have increased, active layers have deepened, and palsa areal extents have decreased considerably since the 1940s. High-altitude palsas thawed quickly from the 1940s to the 1980s, although some low-altitude palsas have recently decreased rapidly in areal extent due to peat-block calving. The linear rate of increasing active-layer thickness may not be congruent with the non-linear rate of areal loss of palsas. The rapid and episodic collapse of palsas at some sites highlights the necessity to consider hydrology, vegetation cover, landscape position, and morphology in palsa dynamics in addition to a warming climate.

Original languageEnglish
Pages (from-to)619-633
Number of pages15
JournalPermafrost and Periglacial Processes
Volume28
Issue number4
DOIs
Publication statusPublished - 1 Oct 2017

Scopus Subject Areas

  • Earth-Surface Processes

User-Defined Keywords

  • active-layer thickness
  • linear mixed-effect models
  • long-term monitoring
  • Mackenzie/Selwyn Mountains, Northwest Territories
  • non-linearity
  • palsa
  • permafrost

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