According to the findings, there was a serious temperature drop in Europe at that time. This led to the expulsion or death of a group of the archaic human species, Homo erectus, who arrived in the region.
University College London paleoclimatologist Chronis Tzedakis and his team have found evidence of cooling in marine sediment collected from the ocean floor off the Portuguese coast.
Principal isotope analyzes of marine plankton remains collected from both the ocean surface and floor also showed a sudden cooling occurred about 1.1 million years ago. Evidence was also supported by analysis of pollen grains from terrestrial vegetation.
Tzedakis stated that the water temperature near Lisbon, which is around 21 degrees on average today, dropped to 6 degrees at that time.
This previously unknown cooling was probably caused by the northerly ice moving south.
Tzedakis states that the planet has gone through multiple cold and hot phases, with an ice age reaching its peak about 900,000 years ago.
Although there were speculations that this cooling may have occurred earlier, no evidence was found.
How did it affect people?
Climate scientist Axel Timmermann, one of the research team, created models for how people would be affected by this cooling at the time.
Timmermann, who works at the Institute of Basic Sciences in South Korea, concluded that the weather at that time was too cold for archaic humans to survive.
It is estimated that these people’s physiology is not suitable for the cold, and they have difficulties in finding food, plants and meat.
The article, published in the peer-reviewed scientific journal Science, writes that this cooling also coincides with what was previously known about human habitation on the continent.
Fossils and stone tools collected at the site showed that Homo erectus arrived in Europe from Asia between 1.4 and 1.8 million years ago.
Previous studies also suggested a sharp decline in population 1.1 million years ago.