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Glaciers in Switzerland |
June
2009
Ice
volume of Switzerland's glaciers calculated |
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Switzerland's
glaciers have lost twelve percent of their ice volume since 1999. This
is the result of a new procedure developed by scientists at ETH Zurich.
The water stored in Switzerland's glaciers currently equates to about two
thirds of the volume of Lake Geneva.
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Rottalgletscher
(Kanton Bern) |
Swiss
glaciers have lost a lot of ice in recent years due to increased melting.
As temperatures climb, so do the fears that the glaciers could one day
disappear altogether. Until now it could only be estimated approximately
how big the ice volume in the Swiss Alps actually is and how it has changed
in recent years. A team of scientists headed by Martin Funk, ETH-Professor
at the Laboratory of Hydraulics, Hydrology and Glaciology (VAW) at ETH
Zurich, however, has now developed a novel procedure for determining the
ice volume of a glacier. Their results are presented in the current issue
of Global and Planetary Change.
The
researchers developed the new method according to the law of mass con-servation,
which states that the surface mass balance has to be balanced by the ice
flow and the change in ice thickness. This allows to infer on the ice thickness
distribution of a glacier from the surface topography by estimating the
mass balance distribution. "The calculation of the current ice volume is
the most important indicator in predicting future glacier changes", explains
Martin Funk.
74
km3 of glaciers |
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The
scientists applied the procedure to the 59 Swiss glaciers larger than three
square kilometers. For the remaining 1'400 glaciers, the ice volume was
estimated by using an empirical area-volume approach derived from the new
generated data set. The total glacier ice volume in 1999 was estimated
to 74 km3, with an accuracy of 9 km3. This means the total volume of all
glaciers of Switzerland is smaller than that of the Lake Geneva, which
has a water volume of 89 km . With a glaciated land area of 1'063 km2,
the Swiss glaciers have an average ice thickness of 70 meters. |
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The
scientists also discovered that the 59 larger glaciers account for almost
88% of the ice volume, whereas about 24% is stored in the Aletsch region
alone (the Oberaletschgletscher, Mittelaletschgletscher and Great Grosser
Aletschletschgletscher). The area of the Great Aletsch Glacier is approximately
the same as the total area of all the Swiss glaciers smaller than one square
kilometer. However, they have an overall ice volume that is twenty times
smaller than that of the Grosser Aletschgletscher . "This just goes to
show that the large glaciers carry the most weight in determining a region's
ice volume", explains Funk.
Volume
decreased by 12 percent |
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The
ETH Zurich study also revealed a change in the ice volume since 1999. Over
the last decade - the warmest for 150 years - Switzerland's glaciers have
lost 9 km of ice (-12%), including 2.6 km (-3.5%) in the record-breaking
summer of 2003 alone. These figures are all the more alarming as the climate
continues to warm up and the temperatures in the Swiss Alps are expected
to increase by 1.8 degrees in the winter and 2.7 degrees in the summer
by 2050.
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Source:
ETH Zürich, Laboratory of Hydraulics, Hydrology and Glaciology (VAW),
June 2009 |
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