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University Distinguished Lecture
Unique Insights to the Earth's Climate History
Preserved in its Cryosphere
ABSTRACT
The chemical and physical properties preserved in the Earth's
cryosphere (glaciers, ice caps and ice sheets) provide proxy records
that contribute prominently to our knowledge of the Earth's past
climate, the ultimate yardstick against which the significance of
present and projected climate change will be assessed. These records
continuously advance our understanding of the mechanisms controlling
the Earth's complex climate system and provide an independent test for
climate models used to project the future consequences of human
activities. The ice core proxy records now reveal that the climate
system is experiencing both rapid and unprecedented changes on time
scales that range from decades to centuries. There is concern that the
Greenland ice sheet may now be losing mass and contributing to sea
level rise. Yet the Antarctic ice sheet may be gaining mass and
offsetting meltwater from Greenland. Additional monitoring and
modeling are essential. In contrast, observations from widely
dispersed parts of the globe - from the glacier fields of Alaska to
the remnants of ice atop Mount Kilimanjaro - confirm that most of the
remaining ice on the Earth is rapidly disappearing. The anticipated
impacts of this rapid and extensive loss of high mountain glaciers
include regional hydrological disruptions in agriculture and power
generation, a modest contribution to sea level rise and the eventual
loss of unique paleoclimate histories by virtue of those ice cores
that will never be recovered.
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