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Updated December 11, 2003
The human imprint on the environment
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Angel glacier, Jasper
National Park, Alta.
©2003 ICN-RCI / Hemera |
In the Americas,
the great human adventure began late—well after the colonization
of Europe, Asia and even
Australia.
Some 25,000 years ago, masses of ice coated much of the planet, locking
up a large proportion of its water reserves. As ocean levels fell substantially
and vast stretches of new land emerged between 25,000 and 14,000 years
ago, a land bridge linked Asia and North
America across what is now the Bering Strait.
Animal herds, and hunters pursuing them, crossed the land bridge and reached
an ice-free zone that extended over what is now part of Alaska,
the Yukon and the Northwest
Territories.
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Athabasca glacier,
Rockies
©2003 ICN-RCI / Hemera |
A colossal wall of ice initially blocked their route to the south. Later,
when a corridor formed in the ice, groups made their way along it in an
odyssey that was to lead them to the southern tip of the Americas.
From what is known at present, this is the most likely theory of how human
beings arrived in the Americas.
While it is not impossible that peoples from Oceania,
Asia or even Europe reached
American shores by sea, there is no irrefutable evidence to support such
a theory.
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