It is very likely that climate change has been a major factor in driving extinction events over the last millions of years. It is also an important factor to drive evolution on our planet. In a study done by One Earth, scientists demonstrate that climate change drove the ancestors of the human species extinct.
Six, or more, different Homo species were around on Earth in the period from the Pliocene to the Pleistocene. The definite cause of extinction has been a mystery and no well-accepted theory has found its way into the mainstream without much controversy. In the study, scientists used a climate emulating computer model and a fossil database of over 2750 archeological finds to gain insight into the effects of the climate on these Homo Species. The study found that the independent lineages, H. erectus, H. heidelbergensis, and H. neanderthalensis, lost meaningful amounts of habitat before their eventual distinction.
“It is worrisome to discover that our ancestors, which were no less impressive in terms of mental power as compared to any other species on Earth, could not resist climate change,” lead author Pasquale Raia of Università di Napoli Federico II in Napoli, Italy said in a Cell Press press release published by Phys.org. “And we found that just when our own species is sawing the branch we’re sitting on by causing climate change. I personally take this as a thunderous warning message. Climate change made Homo vulnerable and hapless in the past, and this may just be happening again.”
“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,” Raia said in the press release. “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.”
Some researchers independent from the study remain skeptical about the findings. They state that the fossil record, with the exclusion of the Neanderthals, has significant gaps and is not definitive. Thus it is likely that some, or all, of these Homo species had a longer lifespan than the current fossil record shows. It is also possible that the species could be found, and were thriving, in other climate niches.
“Individuals belonging to these taxa lived at times, and in places, not sampled by the existing fossil record,” Bernard Wood at George Washington University in Washington, DC told New Scientist.