Climate change may have pushed ancient humans to extinction – now. Powered by Northrop Grumman

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Throughout Earth’s history, climate change has pushed animal and plant species to extinction. Around 250 million years ago, global warming triggered by massive volcanic eruptions wiped out 96% of all marine species during the Permian Period, such as Science magazine details. Now some researchers believe climate change did the same for ancient humans.

A research team led by Pasquale Raia of the University of Naples Federico II in Italy has crossed nearly 3,000 archaeological records of human species with temperature, precipitation and other meteorological data over the past 5 million years . Their findings, published in A land, suggest that episodes of global cooling influenced human evolution, leading three of modern man’s cousins ​​to extinction.

Although some scientists believe that the fossil record of ancient humans is not detailed enough to draw such conclusions, Raia believes her team’s research offers people today a warning from the past of human evolution.

“It is disturbing to discover that our ancestors, who were no less impressive in terms of mental power compared to any other species on Earth, could not withstand climate change,” he said in a press release published by EurekAlert.

Climate niche

Modern humans, called Homo sapiens, are part of the genus Homo, which has been around for at least 2.8 million years. Several different species of Homo lived on Earth during this time, and archaeological records show some had the intelligence to control fire, establish social networks, make stone tools, and create clothing. Although these signs reveal clues to technological and cognitive skills, only H. sapiens survived.

Why? So far, no one knows. The researchers note in One Earth that “no coherent explanation has yet been offered, despite the enormous importance of the matter.”

Raia, an evolutionary biologist, teamed up with more than a dozen other scientists to investigate. They tapped into a fossil database that contained 2,754 archaeological records to map where and when six different species of Homo lived over time, such as Sapiens reports. The researchers also used a statistical modeling technique called a past climate emulator to reconstruct ancient climatic conditions in the places where the six species lived, dating back 5 million years.

Then, they analyzed the environmental conditions at particular times and found that the climate had suddenly changed for three species – H. erectus, H. heidelbergensis and H. neanderthalensis – just before their last known appearance in the fossil record, according to The scientist. Specifically, it became colder for all three, wetter for H. erectus and drier for H. heildelbergensis and H. neanderthalensis.

The researchers used techniques from the field of conservation biology to assess whether these species may have been vulnerable to climate change. For example, H. erectus, which lived about 110,000 years ago on what is now the Indonesian island of Java, lived in hot and humid conditions. But depending on the climate model, an ice age may have created temperatures that were too cold for the species to adapt.

Their analysis shows that climate change occupied more than half of the niche of H. erectus and H. heidelbergensis before their disappearance – as well as a quarter of the niche of H. neanderthalensis. Changing habitats and increasing cold have likely limited food sources and threatened the survival of those more accustomed to warmer climates.

The domino effect of environmental change

Debates rage on how and why ancient humans died out. Several researchers not involved in this study pointed out that the fossil record of human evolution is scarce and less reliable as it goes back in time. Others say that the last appearance of fossilized remains at a given location may not mean that the species was extinct at that time – it may just mean that fossils of later dates have not yet been discovered, such as The Scientist reports. Further analysis and studies of animals and plants from these same places and times may give credit – or not – to Raia’s hypothesis.

In the EurekAlert press release, Raia says he agrees with the comments of his colleagues but that his team’s main conclusions “are true under all assumptions” and serve as a warning as the planet is facing unprecedented climate change. “We were surprised by the regularity of the effects of climate change,” says Raia. “It was perfectly clear, for the extinct species and for them only, that the climatic conditions were just too extreme just before the extinction and only at this precise moment.”

Does this mean modern humans could be extinct? According to Smithsonian National Museum of Natural History, human evolution occurred during one of the most dramatic eras of climatic instability in Earth’s history. Ancient humans faced many extreme challenges, including disease, injury, and predation, and species that adapted survived.

But for modern humans, time may be running out. the The United Nations says the planet has less than 10 years to avoid irreversible damage. And while humans can rely on technological know-how to stay alive, the plants and animals they depend on for food could succumb to higher temperatures, more acidic oceans, and other changes. environmental, creating a domino effect that could make life on Earth more and more. precarious, as the researchers detailed in Scientific reports.

“Personally, I take this as a thunderous warning message. Climate change has made Homo vulnerable and powerless in the past, and it may well happen again, ”says Raia.

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