Early Human Species to Likely Driven to Extinction by Climate Change

Of the six or more different species of early humans, all belonging to the genus Homo, only we Homo sapiens have managed to survive. Now, a study reported in the journal One Earth today (October 15, 2020) combining climate modeling and the fossil record in search of clues to what led to all those earlier extinctions of our ancient ancestors suggests that climate change — the inability to adapt to either warming or cooling temperatures — likely played a major role in sealing their fate.

“Our findings show that despite technological innovations including the use of fire and refined stone tools, the formation of complex social networks, and — in the case of Neanderthals — even the production of glued spear points, fitted clothes, and a good amount of cultural and genetic exchange with Homo sapiens, past Homo species could not survive intense climate change,” says Pasquale Raia of Università di Napoli Federico II in Napoli, Italy. “They tried hard; they made for the warmest places in reach as the climate got cold, but at the end of the day, that wasn’t enough.”

To shed light on past extinctions of Homo species including H. habilis, H. ergaster, H. erectus, H. heidelbergensis, H. neanderthalensis, and H. sapiens, the researchers relied on a high-resolution past climate emulator, which provides temperature, rainfall, and other data over the last 5 million years. They also looked to an extensive fossil database spanning more than 2,750 archaeological records to model the evolution of Homo species’ climatic niche over time. The goal was to understand the climate preferences of those early humans and how they reacted to changes in climate.

Their studies offer robust evidence that three Homo species — H. erectus, H. heidelbergensis, and H. neanderthalensis — lost a significant portion of their climatic niche just before going extinct. They report that this reduction coincided with sharp, unfavorable changes in the global climate. In the case of Neanderthals, things were likely made even worse by competition with H. sapiens.

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