Geoscience Reference
In-Depth Information
Table 2.1
Major Arctic ice caps
Name/Region
Surface area (10
3
km
3
)
Devon Is.
16.6
Ellesmere Is.
77.2
Axel Heiberg Is.
12.6
Barnes (Baffin Is.)
6.0
Penny (Baffin Is.)
6.0
Iceland
11.3
West Spitzbergen
36.6
Northeast Land
14
Franz Josef Land
13.7
Novaya Zemlya
23.6
Severnaya Zemlya
18.3
Greenland Ice Sheet
1710
Greenland glaciers/ice caps
48.6
Sources
: From Field (
1975
); Govorukha (
1988
); and Williams and
Ferringo (
2002
).
Hemisphere. The ice sheet covers an area of 1.71 million km
2
, and contains an
ice volume of 2.93 x 10
6
km
3
(Bamber, Layberry, and Gogineni,
2001
), which if
completely melted is equivalent to a sea level rise of about 7 m. There is a central
dome rising to 3,200 m elevation and a subsidiary dome in Southern Greenland. A
detailed map is provided at
Figure 8.1
. The dimensions of the other Arctic ice caps
are insignificant by comparison (see
Table 2.1
), although they exert an influence on
the local climate conditions. Paralleling the pattern for the Greenland ice sheet (see
Chapter 8
), the net mass balance of most Arctic ice caps and glaciers has turned
negative (Dyuergerov and Meier,
1997
)
Based on data through the middle 1990s, Approximately 40 percent of the sur-
face of the Greenland Ice Sheet saw surface melt during summer (Abdalati and
Steffen,
1997
), both the areal extent of surface melt and melt intensity show general
upward trends over the past several decades (Tedesco et al.,
2010
). For several days
in early July 2012, nearly the entire ice sheet experienced a brief period of surface
melt, including the summit. Although this was the first time in the satellite record
that the summit has seen melt, there is evidence in ice core data of similar events
occurring several times over the past few thousand years. This is again discussed in
more detail in
Chapter 8
.
In sharp contrast to the Antarctic, there are only a few small ice shelves (floating
shelves of glacier ice connected to the shore) in the Arctic. Until fairly recently, the
Ward Hunt Shelf extended about 100 km along the north coast of Ellesmere Island
(Jeffries,
1992
; Mueller, Vincent, and Jeffries,
2003
). It was up to 20 km wide, occu-
pied three fiords and was 40-50 m thick. Since the early 1900s, however, its size
has been greatly reduced and there have been many calving events leading to the
formation of ice islands that may drift around the Arctic Ocean for many years An
