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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