Trends and outlook for high latitude ing trends were observed in the North Slope region of
(Arctic) permafrost Alaska from long-term monitoring sites
16
.
There has been a general increase in permafrost tempera- Temperature monitoring in Canada indicates a warming
tures during the last several decades in Alaska
4–6
, north- of shallow permafrost over the last two to three decades.
west Canada
7–9
, Siberia
10–13
, and northern Europe
14,15
. Since the mid-1980s, shallow permafrost (upper 20-30
m) has generally warmed in the Mackenzie Valley
7,17,18
.
Permafrost temperature records have been obtained The greatest increases in temperature were 0.3 to 1°C per
uninterrupted for more than 20 years along the Inter- decade in the cold and thick permafrost of the central and
national Geosphere-Biosphere Programme Alaskan northern valley (Figure 7.3). In the southern Mackenzie
transect, which spans the entire continuous permafrost Valley, where permafrost is thin and close to 0°C, no
zone in the Alaskan Arctic. Records from all locations significant trend in permafrost temperature is observed
7

along the transect show a substantial warming during (Figure 7.3). This absence of a trend is probably due to the
this period. The permafrost typically warmed by 0.5 to fact that this permafrost is ice-rich; a lot of heat is absorbed
2°C, depending on location (Figure 7.2). Similar warm- to melt the ice before an actual temperature change occurs.
Temperature at Temperature at
20 m depth (°C) 10-12 m depth (°C)
-4
0
Fort Simpson (10 m)
Happy Valley
-5
Northern Alberta (10 m)
Galbraith Lake
-6
-0.5
Wrigley (12 m)
-7
Franklin Bluffs
Deadhorse
-1
-8
Norman Wells
-9
(12 m)
West Dock
-1.5
-10
1980 1985 1990 1995 2000 2005 1986 1989 1992 1995 1998 2001 2004
Figure 7.2: Changes in permafrost tem- Figure 7.3: Ground temperatures at depths
peratures during the last 23 to 28 years of 10 or 12 m between 1984 and 2006 in
in northern Alaska. Temperatures are the central (Norman Wells and Wrigley)
measured at 20 m depth, at which there is and southern (Fort Simpson and North-
no seasonal temperature variation in the ern Alberta) Mackenzie Valley, showing
permafrost. increases of up to 0.3°C per decade.
Source: V.E. Romanovsky; updated from Osterkamp 2003
5
Source: S. Smith; updated from Smith and others 2005
7
184 GLOBAL OUTLOOK FOR ICE AND SNOW