Cryosols in a Changing Climate - Cryopedology - page 152

Ground temperature ( ° c)

2

1

0

-1

-2

-3

1930 1940 1950 1960 1970 1980 1990 2000

1 m 0.5 m 0.3 m 0.08 m

Fig. 12.1 Simulated mean annual ground temperature at Bonanza Creek, Fairbanks, Alaska, from
1930 to 2003 (Romanovsky 2004 )

Global Trends Network-Permafrost (GTN-P), we fi nd that the MAGT warmed
throughout the world's permafrost region, with values ranging from 0.1 to 0.7 °C
per decade for the past several decades in high-mountain regions of the world, 0.3-
0.7 °C per decade in arctic Alaska, and 1.0 °C per decade in North Victoria Land,
Antarctica (Table 12.1 ) (Fig . 12.1 ).
Permafrost temperatures for several stations in Antarctica, the Arctic, and high-
mountain regions are given in Table 12.2 . Permafrost that is −3 °C or warmer is
considered to be “warm” permafrost and is very susceptible to thawing from climate
warming (Fig. 12.2 ).

12.4 Possible Impacts on Soil Properties

In the Arctic continued warming can be expected to increase the ice-free area. An
increase in shrubs (Loranty and Goetz 2012 ) and net primary production of vascular
plants has already been observed (Chapin et al. 1995 ), which will likely increase
soil organic C and N. Thickening of the active layer, especially in areas of sporadic
and isolated permafrost, has resulted in an increase in thermokarst (Lenz et al. 2013 )
and likely will result in an increase in redoximorphism and pervection (see Table
8.5 ) . In the High Arctic increased precipitation may reduce salinization. These same
changes can be expected in areas with alpine cryosols.