New Research Suggests Extreme Glacial Cooling Caused Early Human Extinction in Europe
Scientists from University College London (UCL) have uncovered evidence that an extreme glacial cooling period around 1.1 million years ago in southern Europe likely led to the extinction of early humans on the continent. This discovery challenges the previously held belief that there was continuous human occupation in Europe during that period.
The research, published in the journal Science, reveals that paleoclimate evidence indicates a significant drop in temperature in southern Europe approximately 1.1 million years ago. This climate shift is believed to be responsible for the disappearance of early human populations in the region.
The oldest known human remains in Europe, recovered from Iberia, suggest that early humans arrived from southwest Asia around 1.4 million years ago. The climate at that time was generally warm and wet, with occasional mild cold periods. It was previously believed that once humans arrived, they were able to survive through multiple climate cycles and adapt to increasingly harsh conditions 900,000 years ago.
Professor Chronis Tzedakis, senior author of the study, stated, “Our discovery of an extreme glacial cooling event around 1.1 million years ago challenges the idea of continuous early human occupation of Europe.”
The team of scientists from UCL, the University of Cambridge, and CSIC Barcelona analyzed the chemical composition of marine micro-organisms and examined the pollen content in a deep-sea sediment core off the coast of Portugal. This analysis revealed abrupt climate changes that culminated in extreme glacial cooling, with ocean surface temperatures dropping below 6°C and semi-deserts expanding on the adjacent land.
Lead author Dr. Vasiliki Margari expressed surprise at the findings, saying, “To our surprise, we found that this cooling at 1.1 million years ago was comparable to some of the most severe events of recent ice ages.”
Co-author Professor Nick Ashton of the British Museum noted, “A cooling of this magnitude would have placed small hunter-gatherer bands under considerable stress, especially since early humans may have lacked adaptations such as sufficient fat insulation and also the means to make fire, effective clothing, or shelters.”
To assess the impact of the climate on early human populations, the researchers ran a simulation on their supercomputer Aleph and developed a human habitat model, which predicted how suitable the environment was for early human occupation. The results showed that the climate around the Mediterranean became too hostile for early humans 1.1 million years ago.
The paleoclimate data and human habitat model results indicate that Iberia, and southern Europe in general, was depopulated during the Early Pleistocene. The lack of stone tools and human remains over the next 200,000 years further supports the possibility of a long-lasting hiatus in European occupation.
Co-author Professor Chris Stringer of the Natural History Museum in London commented, “According to this scenario, Europe may have been recolonized around 900,000 years ago by more resilient humans with evolutionary or behavioral changes that allowed survival in the increasing intensity of glacial conditions.”
The study, titled “Extreme Glacial Cooling Likely Led to Hominin Depopulation of Europe in the Early Pleistocene,” was a collaboration between UCL Geography, the IBS Center for Climate Physics at Pusan National University, and several other research institutions.
Further research is needed to fully understand the impact of extreme climate events on early human populations and their subsequent migration patterns.