NEW research has revealed more about how the last ice age impacted the migration of humans.
The research shows how the circulation and climate of the North Pacific effected early human migration from Asia to North America.
The project was led by the School of Earth and Environmental Sciences at the University of St Andrews.
The Pacific Ocean contains around half the water in Earth’s oceans and is a vast reservoir of heat and CO2
However, at present, the slow circulation of North Pacific restricts this heat and CO2’s movement, limiting its impact on climate.
The international team of scientists used sediment cores from the deep sea to reconstruct the circulation and climate of the North Pacific during the peak of the last ice age.
The results revealed a dramatically different circulation in the ice age Pacific, with strong ocean currents creating a relatively warm region around the modern Bering Sea.
Dr James Rae, from the University of St Andrews who led the study said: “Our data shows that the Pacific had a warm current system during the last ice age, similar to the modern Atlantic Ocean currents that help to support a mild climate in Northern Europe”
The warming from these ocean currents created conditions more favourable for early human habitation, helping address a long-standing mystery about the earliest inhabitants of North America.
Professor Ben Fitzhugh, an anthropologist at the University of Washington and co-author of the study said:“According to genetic studies, the first people to populate the Americas lived in an isolated population for several thousand years during the peak of the last ice age, before spreading out into the American continents”
The new research suggests that these early Americans may have lived in a relatively warm refugium in southern Beringia, on the now submerged land beneath the Bering Sea.
Due to the cold climate that dominated other parts of this region during the ice age, it has been unclear, until now, how habitable conditions could have been maintained.
Dr Will Gray of the LSCE institute in France said: “The warm currents revealed by our data would have created a much more pleasant climate in this region than we might have previously thought”,
“This would have created milder climates in the coastal regions of the North Pacific, that would have supported more temperate terrestrial and marine ecosystems and made it possible for humans to survive the ice age in an otherwise harsh climatic period.”
“Our work shows how dynamic Earth’s climate system is.
Dr Will Gray of the LSCE institute in France added:”Changes in the circulation of the ocean and atmosphere can have major impacts on how effectively humans may inhabit different environments, which is also relevant for understanding how different regions will be affected by future climate change”
