 |
| Titel |
Estimating the glacier contribution to sea-level rise over the past 200 years |
| VerfasserIn |
Paul Leclercq, Johannes Oerlemans  , Graham Cogley |
| Konferenz |
EGU General Assembly 2011
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250054492
|
|
|
|
|
|
| Zusammenfassung |
| There is abundant evidence that eustatic sea level has been rising for at least the past two
centuries. Although the error bars are significant, the general view is that this rise has been
between 15 and 25 cm for the period 1850-2000. Thermal expansion of ocean water, changes
in terrestrial storage of water, mass loss of smaller ice caps and glaciers, and possible
long-term imbalances of the mass budgets of the Greenland and Antarctic ice sheets have
been listed as the most important processes contributing to the observed sea-level rise. In
order to make reliable future projections of sea-level rise, it is really crucial to understand,
and be able to reproduce, the contribution of each of these components over the past
centuries.
In this study, we present a new estimate of the contribution of glaciers and small ice caps
to the sea-level rise over the period 1800-2005. We directly use data on geometric changes of
glaciers. Hereby, we avoid the problems associated with the modelled mass balance
sensitivity approach that needs climate data as input and has the problem of defining an
proper initial state.
Length records form the only direct evidence of glacier change that has potential global
coverage before 1950. Hence, we exploit the available information on changes in glacier
length. At the moment, we have 335 glaciers length records worldwide that start before 1945.
The length changes of these glaciers show a worldwide coherent signal; from the middle of
the 19th century up to present glaciers retreated. We calculate a globally representative signal
from the 335 glacier length records. By means of scaling, we deduce a global glacier volume
signal, that is calibrated with the mass-balance and geodetic observations of the period
1950-2005. We find that the glacier contribution to sea-level rise was 8.2 ± 2.1 cm for the
period 1800-2005 and 9.1 ± 2.3 cm for the period 1850-2005. These values are significantly
larger than previous estimates, for instance as reported in the latest IPCC report. |
|
|
|
|
|
|