A study on the influence of climate change on human evolution

A map of the habitats of the various human species
An article published in the journal “Nature” reports the results of a research on the correlation between climate changes that occurred over the last two million years and the evolution of human beings. A team of researchers led by Axel Timmermann, director of the IBS Center for Climate Physics (ICCP) at Pusan ‚Äč‚ÄčNational University, South Korea, used ICCP’s Aleph supercomputer to simulate climate history. The results were compared with the largest database of human fossils and archaeological artifacts built under the direction of Pasquale Raia of the University of Naples Federico II, Italy. The result was that the best habitats for the human species that existed in these two million years match the climatic changes caused by the oscillation of the Earth’s axis and the periodic changes in the shape of the Earth’s orbit.

Research on the influence of climate change on the evolution of the human species has been going on for a long time because its importance was already widely recognized. The problem was in the scarcity of paleoclimatic data and information on the environments in which the various species of the genus Homo lived. Over the years, a lot of information has been collected and now technological advances make it possible to create climatological models and simulations of climate change that offer the possibility of trying to understand how human evolution was influenced by environmental changes.

This type of study spans various scientific disciplines. Simulations require knowledge of climatology and computer science. Climate change occurs for a number of causes and among them, there are astronomical processes linked to some variations of the Earth’s orbit and axis. Correlations with human evolution require paleontological and archaeological examinations.

The history of humanity is complex and there are discussions on the classification of the various species assigned to the genus Homo and the relationships between the different species. In this study, five species were included considering the Early African Homo, Homo habilis, and Homo ergaster, in one group, Homo erectus, Homo heidelbergensis, Homo neanderthalensis, and Homo sapiens.

As far as possible, the results of the climate simulation were verified by comparing them with the available data, which were found to be in agreement. The results were combined with the largest database of paleontological and archaeological information regarding the places and times in which the various human species lived. That combination particularly showed the influence of astronomical cycles related to the Earth and its orbit. Different human groups preferably lived in environments with different climates but these were habitats made more suitable for those groups by climatic changes caused by astronomical cycles.

The top image (Courtesy Axel Timmermann et al. All rights reserved) shows a map of the habitats of the various human species which also includes the Denisovans, a species known only thanks to a few well-preserved bones that allowed the extraction of DNA. The Denisovans are also included in the family tree on the left which indicates the various stages of human evolution estimated thanks to this study.

The bottom image (Courtesy Axel Timmermann. All rights reserved) shows the optimal habitats obtained from the simulations for Homo heidelbergensis, Homo neanderthalensis, and Homo sapiens, which have various overlaps with the relative time scales. The overlaps could indicate a succession of species with Neanderthals that evolved from Homo heidelbergensis in Europe while Homo sapiens evolved from Homo heidelbergensis in Africa.

Successions and interbreedings between populations of different species are complex to trace but make up important parts of the history of humanity. A study like this can provide new information and suggest times and places where they may have occurred.

Future studies that will include climate models should also take into account the complexity of ecosystems and therefore the changes in flora and fauna occurring in the various habitats. This requires adding plant and animal fossil databases. These are long and complex studies that can offer valuable insights into the recent history of life on Earth. These are studies that show the influence of natural phenomena, including astronomical ones, on human beings before they developed tools sophisticated enough to dominate their environment to the point of having an influence on the climate themselves.

The optimal habitats obtained from the simulations for Homo heidelbergensis, Homo neanderthalensis, and Homo sapiens

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