Abstract

The Greenland ice sheet contains about a tenth
of the world’s fresh water, and if it were to melt
would cause a 7 m rise in global sea-level
(Intergovernmental Panel on Climate Change
(IPCC) 2001). The ice sheet covers 82% of the
total area of Greenland (Ohmura
et al.
1999).
It is a huge ice dome, with two main peaks: one
at 3220 m at Summit (about 728N, 298W), and
the other at 2850 m in the south at about 648N,
448W (Philip 1999) (Fig. 1). The ice sheet is
up to about 3 km thick in the middle, and its
great weight depresses the underlying crust
which assumes the concave shape of a saucer.
The ice sheet has waxed and waned in response
to natural changes in insolation and climatic
feedbacks over millennia.