Early humans in Europe were likely wiped out by a big freeze

11 Aug 2023

Image: © Manuel Mata/Stock.adobe.com

An international study published in Science suggests that a gap in the continuous inhabitation of Europe can be explained by ‘extreme glacial cooling’.

While we worry about increasingly frequent heatwaves and rapidly rising average temperatures, early humans in Europe had a very different problem to deal with – severe cold.

In fact, a new study conducted by scientists in the UK, South Korea and Spain has found that early humans that once lived in Europe may have been wiped out by a catastrophic decline in average temperatures across the continent as a result of “extreme glacial cooling”.

The earliest evidence of human existence in Europe traces back to between 1.1m and 1.5m years ago in present-day Spain. But the latest study punctures the idea that humans have continuously inhabited the continent.

Human inhabitation of Europe started with homo erectus – our direct ancestor that left Africa and spread to parts of Europe, Asia and beyond. But there is a gap of around 200,000 years between 1.1m and 900,000 years ago – during which time the cooling is predicted to have happened.

A team of 11 researchers from institutions including University College London, University of Cambridge and the IBS Centre for Climate Physics in Busan, South Korea, found that the newly discovered cooling event was “comparable to the most extreme events of the last 400,000 years”.

“Contrary to previous beliefs, our study demonstrates that human occupation of Europe was not continuous, but rather punctuated by at least one regional climate-induced extinction,” climate physicist and co-author Prof Axel Timmermann told Reuters.

While sub-zero temperatures are not unthinkable for modern humans to survive in, thanks to advanced heating facilities and relatively abundant availability of food, early humans are not thought to have adapted to such extreme weather conditions.

“There is no direct evidence that they could even control fire at this time,” Timmermann said. “Therefore, the extremely cold and dry conditions over Europe and the corresponding lack of food, must have greatly challenged human survival.”

Published in the journal Science yesterday (10 August), the international study involved reconstructing the ancient climate based on organic compounds left by tiny algae and pollen content in a deep-sea sediment core drilled off Portugal’s coast.

These sediments revealed temperature and vegetation changes, and computer simulations run during the study show that average temperatures dropped about 4.5 degrees Celsius during this time, possibly explaining the gap in recorded human existence in Europe.

“The ability to estimate these past environments permits us to better understand the forces that shaped our evolution,” said Sacha Vignieri, deputy editor for research at Science.

“Using climate models to estimate past environments and spatial distribution models to predict species occurrence, [this study and others] now reveal details about hominin evolution that fossils alone cannot.”

10 things you need to know direct to your inbox every weekday. Sign up for the Daily Brief, Silicon Republic’s digest of essential sci-tech news.

Vish Gain is a journalist with Silicon Republic