Climate shift may have spurred migration across now submerged land bridge

St Paul Island in the Bering Sea. Credit Matthew Wooller

A new study by Canadian, UK and US researchers has found that climate conditions shifted to become wetter and warmer around 15,000 years ago and contributed to the first human migration between Asia and North America.

A stretch of land known as the Bering Land Bridge once connected what is today Russia and Alaska, when sea levels were much lower during the last glaciation. This was an important bridge because it provided an opening for the dispersal of people and animals from Asia into the Americas.



Led by University of Alaska Fairbanks (UAF), working with geographers at the University of Southampton (UK), the research team was able to gauge climate conditions by studying a 12-metre-long sediment core collected from a lake on St. Paul Island in the Bering Sea.



By analysing organisms in the core, scientists constructed a climate record of the Bering Land Bridge during the past 18,500 years. Almost all of the bridge and evidence of its past conditions is now submerged due to sea level rise.



The study, which also involves the universities of Arizona, Pennsylvania State, Wisconsin-Madison, Mount Allison, New Brunswick, York (Canada) and Plymouth (UK), is published in the journal Royal Society Open Science.

