2023-08-11 11:52:48
Pink shading on the map highlights areas where early human species suffered a major reduction in habitat suitability due to cooling, drought, and reduced food resources. – INSTITUTE FOR BASIC SCIENCE
MADRID, 11 Ago. (EUROPA PRESS) –
1.12 million years ago a massive cooling in the North Atlantic, with changes in climate, vegetation, and food resources, disrupted early human occupation of Europe.
The job, published in science by an international group of scientists from Spain, the United Kingdom and South Korea presents observational and modeling evidence documenting that unprecedented climatic stress changed the course of early human history.
Archean humans, known as Homo erectus, moved from Africa to central Eurasia about 1.8 million years ago. From there they spread to western Europe, reaching the Iberian Peninsula around 1.5 million years ago.
After experiencing initially fairly mild climatic conditions, these groups eventually settled in southern Europe, as documented by various dated fossils and stone tools from this period.
But given the increasing intensity of glacial cycles in Europe beginning 1.2 million years ago, it remains unknown how long early humans lived in this area and whether occupation was interrupted by worsening climatic conditions.
To better understand the environmental conditions experienced by the first human species in Europe, the team of pollen experts, oceanographers, climate modellers, archaeologists and anthropologists combined data from deep ocean sediment cores from the eastern subtropical Atlantic. with new climate model simulations and of human habitats made with supercomputers that cover the period of depopulation.
After screening thousands of tiny plant pollens stored in the core of ocean sediment and analyzing preserved temperature-sensitive organic compounds left behind by tiny algae, which lived more than a million years ago, the scientists found that around 1.127 million years ago years, the climate over the eastern North Atlantic and adjacent land suddenly cooled by 7 degrees C.
“This massive cooling marks one of the first terminal stadial events in the paleoclimate record. It occurred during the last phase of a glacial cycle, when ice sheets disintegrated, releasing large amounts of fresh water into the ocean and causing changes in ocean circulation and a southward spread of sea ice“, says Professor Chronis Tzedakis, from University College London (UCL) and lead author of the study.
Data on pollen extracted from the core of ocean sediments reinforce this hypothesis. “Rivers and winds carry tiny pollen from adjacent land to the ocean, where it sinks and settles in the deep ocean. Based on our analysis of pollen from ocean sediments, the cooling of the North Atlantic transformed the vegetation of western Europe into an inhospitable semi-desert landscape“adds Dr Vasiliki Margari from UCL, lead author of the study.
To quantify how early humans might have reacted to an unprecedented climate anomaly, scientists at the SII Center for Climate Physics (ICCP) in South Korea conducted new computer model simulations for this period.
By adding glacial freshwater to the North Atlantic, ICCP’s Dr Kyung-Sook Yun and Hyuna Kim were able to reproduce key features of the terminal stadium event, such as cooling and drying over southern Europe.
“We then use this global climate model simulation as input to a human habitat model, which determines whether or not certain environmental conditions were suitable for early Homo erectus. We found that, in many areas of southern Europe, early human species such as Homo erectus would not have been able to survive,” describes Professor Axel Timmermann, Director of the ICCP at Pusan National University and co-author of the study.
Although the cooling only lasted about 4,000 years, the lack of stone tools and human remains for the next 200,000 years raises the possibility of a long-term hiatus in European occupation. Europe was repopulated about 900,000 years ago by a group often called Homo antecessor. This group and its descendants were much more resistant, because they were able to adapt to the increasing intensity of glacial conditions over Europe.
“Our study of past climates documents the sensitivity of southern European vegetation and human food resources to North Atlantic temperature changes. This result adds to mounting evidence that our human history has been shaped by climate changes of the past,” adds Professor Timmermann.
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