Laboratory Manual for Introductory Geology 4e

FIGURE 15.17 Atmospheric temperatures and CO 2
concentrations over the past
150,000 years, as measured in the Vostok ice cores from Antarctica.
Vostok ice cores 150,000 to 100,000 years ago
Temperature (0°C)
2
Temperature
0
–2
–4
–6
–8
–10
–12
150,000 140,000 130,000 120,000
Years ago
300
280
Carbon dioxide
260
240
220
200
180
110,000 100,000
CO 2
concentration (ppm)
We don’t need sophisticated instruments to understand how glaciers respond to
climate change, however. All we have to do is look. The most dramatic example of
glacial change was witnessed by people all over the globe, who watched on television
as a huge piece of the Antarctic glacier—larger than the state of Rhode Island—
broke off in the summer of 2017. Another notable example involves the Athabasca
Glacier in Jasper National Park, Alberta, Canada, one of the most popular tourist
destinations in the province and the most visited glacier in North America. The
glacier has been retreating since 1843, and the Alberta tourist bureau is concerned
that if the retreat continues, it won’t be long before there won’t be a glacier left to
visit. FIGURE 15.18 dramatically documents the glacier’s retreat.
FIGURE 15.18 Retreat of the Athabasca Glacier, Alberta, Canada.
1843/4
93
1843/4
Old Banff - Jasper
1906
LITTLE
ICE
93
1922
1917
1906
AGE MAXIMUM
1919
1922
1924
Sunwapta River
EXTENT
1843/4
1938
1948
Sunwapta
Lake
1938
1959
1954
CAR
PARK
1948
1959
1843/4
1979
1992
1979
N
0 200
meters approx.
ATHABASCA
GLACIER
1999
(a) The black-and-white photograph from 1906 (top) and the
color photograph from 2006 (bottom) show approximately the
same location. Notice that the glacier is visible only in the far
left-hand portion of the 2006 image.
Produced by: The Cartographic Section, Geography Department,Western, 2003.
(b) Changes in the position of the glacier’s terminus between 1843
and 1999.
15.5 GLACIERS AND CLIMATE CHANGE
405