Life and climate in an ice age - Ice Ages and Interglacials: Measurements, Interpretation, and Models - page 3

Figure 1.1. Distribution of vegetation in North and Central America at the height of the last
ice age (Adams and Faure, 1997).
included Siberia, Alaska and parts of the Yukon. Beringia was bounded by the
then permanently frozen Arctic Ocean and the continental ice sheets. Rain and
snow tended to fall on the high southern ice fields of the Yukon and Alaska, thus
reducing the amount that fell on the Beringian side. At the height of glaciation
the retreat of the sea meant that most of the land was far from maritime influence
and so had an arid, continental climate. The low winter snowfall prevented
glaciers from forming and left grass and other vegetation accessible to grazers
throughout the winter. This is what made Beringia habitable at a time when
much of the land to the south was buried in ice.
As well as creating a dry climate, the ice sheets also made loess—a fine dust
produced by the grinding action of the glaciers and deposited on the edge of
streams emerging from the ice front. Loess blew across Beringia, establishing a
well-draining soil. The result was a land of grassy steppes. An array of tiny plants