36
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Figure 2.1. Ice ages in Earth history (Eyles, 1993).
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Only 3 per cent of glaciers are outside both the great Antarctic and Greenland ice sheets
that constitute the largest fresh water reserve of the hydrosphere (Lvovitch, 1967). The
large polar caps cover an area of 13.6 million km 2, with an average thickness of 2.2 km
and a maximum close to 5 km. The water equivalent volume of ice of this ice sheet is