Over the past 2 million years, much of the Northern Hemisphere was dominated by vast glaciers. This meant that much of the planet’s water was locked up in vast ice sheets, which lead to sea levels up to 150 metres lower than today. This meant that shallow areas of what is the modern day sea became exposed land masses, completely changing the planet’s characteristics.
One of these areas was a land bridge which connected the eastern most reaches of Siberia and the US state of Alaska in place of the Bering Striates. This body of water is approximately 53 miles wide and 50 metres deep, connecting the Arctic Ocean and the Pacific Ocean, whilst separating North America and Asia. Previous fluctuations in global sea level lead to it giving way to the “lost world of the ice age” (Professor Elias) or Beringia.
This land bridge was never covered by ice as the region was too dry for glaciation to occur as the land mass blocked moisture from the pacific, leading to very little snow. This, coupled with the fact that there was a layer of unfrozen soil 20 – 30 cm thick lying on top of the permafrost, allowed grasses and herbs to grow, as well as shrubs in the wetter areas. The vegetation was, in turn, able to support large herbivores such as Mammoths, Horses and Long Horned Bison. Inevitably predators soon followed, leading to Beringia being populated by animals such as the Pleistocene Lion, the Scimitar Cat and of course, Humans.
It is thought that humans migrated to Beringia about 15,000 – 3,500 years ago. This was during a period when the earth’s climate had warmed sufficiently for them to survive here, but the ice sheets had not caught up with the new temperatures. This meant that the sea levels remained low enough for Beringia to not be submerged, whilst humans were able to live here.
There is little archaeological evidence of humans in the area, especially compared to the numerous animal and plant fossils, because permanent settlements were not established. These early humans had to follow the herds, and so lived in tents or caves. There are also no graves, as the permafrost meant that it was impossible to dig below the 30 cm deep active layer. However, there is sufficient evidence for the theory to have developed that this was early humans’ route into the Americas from Asia. Amongst this evidence there are unique carvings of people wearing tailored clothing, which would have enabled them to survive the harsh conditions.
This land bridge began to shrink due to rising sea levels 11,000 years ago, before the continents of Asia and North America were finally separated 10,000 years ago. As the ice receded, humans were able to move down new corridors in the ice sheets, spreading south into Canada- an area which had been dominated by ice. Other animals which had populated Beringia were not so fortunate, most of which became extinct.
Beringia is evidence of the complicated climatic history of our planet, and proves that sea levels fluctuated long before industrialization and the emission of greenhouse gases. However, as well as being an interesting geographical case study, Beringia is also a key piece in our understanding of the history of our species which helped to shape the world as we know it.
Contributed by Matthew Cockerill
This article was written using information from the Yukon Beringia Interpretive Centre’s website, as well as my own notes from a lecture at the Royal Holloway University given by Professor Scott Elias.