Overview of the various models for ice ages in the recent past (3 MYBP to present) - Ice Ages and Interglacials: Measurements, Interpretation, and Models - page 221

Figure 8.4. Schematic of the three modes of ocean circulation that prevailed during different
times of the last glacial period. A section along the Atlantic is shown. The rise in bottom
topography symbolizes the shallow sill between Greenland and Scotland. North Atlantic
overturning is shown by the solid line, and Antarctic bottom water by the dashed line
(Rahmstorf, 2002).

necessarily true. Glaciers grow when the rate of precipitation exceeds the rate of
evaporation and sublimation. An ample source of moisture must be an ingredient
of glacier formation.
Bischof (2000) has suggested that an alternative to the astronomical theory of
solar-driven ice ages

can be achieved by physically moving excessive amounts of ice from the
polar regions to lower latitudes. If, for example, the air pressure distribution over
the Arctic Ocean were such that winds blew from the Bering Strait across the Pole
towards Fram Strait, then massive amounts of pack ice would be moved into the
Norwegian Greenland Sea and push the polar front southward. In the winter,
this process would continuously produce additional sea ice in the open leads
created by the offshore winds in the Bering Strait region, setting in motion
a veritable 'ice machine'. The regional extent of ice and snow cover in the
Norwegian Greenland Sea would increase, cooling the region, and the high

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