Jökull - 01.10.1998, Page 30

glacier variations. Future climate changes will be mon-
itored instrumentally and this will of course give much
more quantitative information about the changes than
is available about past climate changes. Nevertheless,
it is important to monitor glacier variations associated
with future climate changes (Haeberli, 1995). The cli-
matic signal contained in records of glacier variations
has a large area coverage whereas most meteorological
data consist of point measurements. Moreover, the
glacier records document climate changes that occur in
relatively high mountain areas which are often poorly
represented in the meteorological data. Finally, it is im-
portant for the interpretation of past records of glacier
variations to obtain good data on glacier variations as-
sociated with climate changes which are well defined
by measurements.
The interpretation of climate from records of
glacier variations is problematic in a number of ways.
The advance and retreat of surge-type glaciers is un-
related to climate and records from such glaciers must
be eliminated from a data set that is to be used for de-
ductions about climate. The response of non-surging
glaciers to climate changes is influenced by the re-
sponse time of the glaciers, which leads to a delay be-
tween a climate change and the associated response of
the glacier terminus (c/. Jóhannesson and others,
1989).
Glacier variations are not only important because
of local hydrological effects or as indications of cli-
mate changes. Increased runoff from glaciated areas
is important for future global sea level rise that may
occur as a consequence of future climate warming
Fig. 1. Sólheimajökull, S-Iceland, has one of the most complete records of glacier front variations since 1930. Photo: Oddur
Sigurðsson, 30 Oct. 1985. -Sólheimajökull.
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JÖKULL, No. 45, 1998