Download What is Beringia?

What is Beringia?
It was a land of ice, giant mammals and the First People of North America. We live in
unusual times. We may think that our climate today is typical but over the past 2
million years, the climate of the northern hemisphere has been dominated by huge ice
sheets. During each Ice Age, vast glaciers formed in the Northern Hemisphere, locking
up much of the world's water as ice. Global sea levels dropped as much as 100 - 150
meters as a result, revealing the floor of the Bering Sea and creating a land connection
between Alaska and Siberia (shown by the area in green). This land bridge was part of a
larger unglaciated area called Beringia.
Glaciers never formed in Beringia because the climate was too dry. Beringia, clothed in
the hardy grasses and herbs of the tundra, was home to the giants of the Ice Age: the
mammoth, the giant short-faced bear, the steppe bison, and the scimitar cat. At the
height of the last great Ice Age, the most successful hunters of all, human beings,
entered Beringia from Siberia, conquering the last frontier for the human species.
The First Peoples of Beringia
Beringia has played a key role in the evolution and dispersal of our own species. Like
the elephants, our lineage arose in Africa and long ago spread across areas of Eurasia
that offered moderate climates. By 60,000 years ago, and perhaps earlier, some people
embarked upon one of the most remarkable achievements of humankind: they learned
how to live in the far north. Using artifacts made by hand from stone, bone, sinew,
wood, fiber, and moss, they invented secure dwellings and tailored skin clothing. They
developed expert control of fire, including the use of alternative fuels such as animal
dung, finely broken bone, and fat or oil in areas lacking woody plants. They learned to
travel over snow and ice, and they may have invented watercraft with which to cross
dangerously cold rivers. They also learned to cope with long hours of winter darkness.
These ancient people were skilled in many of the arts and sciences we pursue today.
They possessed amazing biological knowledge - the nutritional and medicinal
properties of many plants and the habits and anatomy of many animals. They were
experts at finding stone suitable for flaking into tools and grinding into pigments. They
were probably great storytellers who entertained and educated themselves by passing
on oral histories and knowledge from one generation to another.
We do not yet know exactly when people first reached Beringia and settled there
permanently, but it was the uncovering of the Bering Land Bridge that enabled them to
reach the North American continent. Until recently, it was believed that the last period
of the Bering Land Bridge came to an end around 14,000 years ago and that people must
surely have crossed the land bridge by that time. Recent studies of samples from the
floors of the Bering and Chukchi Seas suggest that the land bridge was totally
submerged around 11,000 years ago. Support for this later date can be found in the
remains of bowhead whales and marine molluscs that would have passed to the
Beaufort Sea from the Pacific Ocean shortly after this time.
Beringia exists today, not as a land bridge but as a seaway. The Bering Strait is only 80
kilometers wide, and a few people have made hazardous crossings of its shifting sea ice.
Of more importance during the past 11,000 years has been the link between the Pacific
and Arctic Oceans. If nature takes its normal course the land bridge will eventually
become exposed again as glaciers advance across the continents and sea level is
lowered. It is too soon to say whether that normal course of events will be diverted by
the effects of global warming arising from the activities of our species.
Post-glacial flooding caused sudden and catastrophic landscape changes. More gradual
changes allowed time for plant and animal adaptation. The current rise in global
temperatures, particularly in the north, is continuing to change the landscape. The arctic
coast is eroding faster than it has in living memory in some areas. Permafrost is melting
and the circumpolar treeline has shifted over the last 50 years.
Above: Permafrost slumping erodes the coastline of the Beaufort Sea. The melting
permafrost expands upslope because meltwater and earth flow downslope, repeatedly
exposing more permafrost to melting
.
Above: The same block failure along the Beaufort coast. The Beaufort Sea undercuts the
cliffs causing large blocks of land to drop into the sea
125,000-year-old tree rings tell us Beringia was warm.
The rings of 125,000 year-old spruce tree stumps found buried in the permafrost near
Fairbanks, Alaska, are amazingly similar to the rings found in spruce in the same area
today. This tells us that the climate of central Eastern Beringia at that time was similar
to, or even warmer than, today's climate.
Left: Spruce tree trunk cut from a log preserved in permafrost in the Eva Forest Bed
near Fairbanks, Alaska. It grew approximately 125,000 years ago.
Right: Cross section of a white spruce tree that was cut in 1990 near Fairbanks, Alaska
at the same elevation as the 125,000-year-old tree. Note how similar the trunk and ring
sizes are to those of the older tree.
Ice Age Gallery of animals:
http://beringia.com/archives/old_site_archive_Sept_2008/iceage.htm
Charlie Lake cave excavation (photo gallery):
http://www.sfu.museum/journey/en/mod/multimedia/photographs/index.php
Watch the ice disappear from the Bering Strait (simulation):
http://instaar.colorado.edu/QGISL/bering_land_bridge/
http://www.ncdc.noaa.gov/paleo/parcs/atlas/beringia/images/movies/lbridge.mov
GREAT full size screen shot of the World Map:
http://kyleabaker.com/wp-content/uploads/2008/06/wallpaper-world-map-2006-large.gif