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| Titel |
Global and hemispheric temperature reconstruction from glacier length fluctuations |
| VerfasserIn |
Paul Leclercq, Johannes Oerlemans  |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250035275
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| Zusammenfassung |
| Temperature reconstructions for recent centuries provide a historical context for the warming
over the twentieth century. They are the essential basis of estimations of the natural
variability in temperature before and during the onset of anthropogenic perturbation. For the
period before meteorological measurements started, as well as for remote regions from which
meteorological series are short or absent, documented glacier fluctuations can provide
valuable information on climate change. We use glacier length fluctuations to reconstruct
annual averaged surface temperatures of the past 400 years on European, hemispherical and
global scales.
We have collected a set of 281 glacier length records starting before 1945. The
majority of the available records is located at the mid-latitudes of the Northern
Hemisphere, but we have also records in the tropics, the Arctic and at the mid-latitudes of
the Southern Hemisphere. Temperatures are derived from glacier length changes
using a linear response equation that has two parameters: the response time and the
climate sensitivity of a glacier. The values of these parameters are estimated for
each glacier by means of a simple model, that is calibrated on numerical model
results.
Our reconstruction is a temperature proxy with decadal resolution that is completely
independent of other temperature records. The global and hemispherical temperatures
reconstructed from glacier length fluctuations are in good agreement with the instrumental
record of the last century. This agreement validates our method. Furthermore our results agree
with existing multi-proxy reconstructions of temperature in the pre-instrumental period. The
temperature record obtained from glacier fluctuations provides an independent confirmation
of the warming of the twentieth century, giving a global cumulative warming of 0.93 ± 0.46
K over the period 1830 - 2000 and a cumulative warming of 0.91 ± 0.79 K over the period
1600 - 2000. |
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