Permafrost temperature states are generally colder further north, as permafrost progresses from discontinuous to continuous. Additionally, according to borehole monitoring sites, permafrost temperatures have generally increased across Canada, Alaska and Siberia over the last half-century. A study (Shiklomanov et al., 2012) has shown that Alaskan permafrost temperatures across the continuous-discontinuous boundary has increased within the last few decades (Figure 1).
Melting rates have been shown to vary across permafrost types and locations. Permafrost that forms at colder temperatures has a lower threshold for change than those that form at higher temperatures. This means that a modification from cold permafrost to warm permafrost will continue to occur. This trend will lead to a more continuous permafrost type across the Arctic.
The active layer thickness (the surface ground layer that melts and freezes seasonally) variation over the last 15 years fluctuates differently across the Arctic (Figure 2). A general, yet inconsistant increase in active layer thickness has been found at most sites, indicating a warming climate. However, some sites (Alaska Coastal Plain & West Siberia) have seen a decrease in active layer thickness (Romanovsky et al., 2012).
Recent Permafrost Trends (IPY)
Permafrost Temperature during IPY (°C)
Permafrost Temperature Change (°C)
Period of Record
-5.0- to -10.0
early 1980s to 2009
Osterkamp, 2007; Smith et al., 2010; Romanovsky et al., 2010
Mackenzie Delta and Beaufort coastal region
-0.5 to -8.0
late 1960s to 2009
Burn & Kokelj, 2009; Burn & Zhang, 2009; Smith et al., 2010
Canadian High Arctic
-11.8 to -14.3
1978 to 2008
Smith et al., 2010; Smith et al., 2012
0.0 to -5.0
1985 to 2009
Osterkamp, 2008; Smith et al., 2010; Romanovsky et al., 2010