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Researchers have sampled an enormous stalagmite in the Pozzo Cucù cave in Italy in order to conduct paleoclimatic reconstruction of the last ice age. Their conclusions have helped answer questions related to the demise of Neanderthals. Source: O. Lacarbonara / University of Bologna

Climate Change Did Not Cause the Demise of Neanderthals

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On August 29th 2018 The Smithsonian Institute announced “Climate records gathered from stalagmites in Romanian caves show two extremely cold dry periods correspond with the disappearance of Neanderthals.” And now, a new study of stalagmites in Italy has announced that “ Homo neanderthalensis did not become extinct because of changes in climate.” What are we make of such an extreme, 180-degree about turn in the scientific community?

The study was published in Nature Ecology & Evolution by a joint team of researchers led by Andrea Columbu from the University of Bologna in Italy and scholars from the University of Innsbruck in Austria, where the isotopic analyses were carried out. The radiometric dating was conducted by researchers from Australia's University of Melbourne and China's Xi'an Jiaotong University , and the original stalagmite samples were collected with assistance from Grotte di Castellana , the Apulian Speleology Association.

The new study has based its findings on the analysis of samples taken from caves on the Murge karst plateau in Apulia, Italy. (Public domain)

The new study has based its findings on the analysis of samples taken from caves on the Murge karst plateau in Apulia, Italy. ( Public domain )

Paleoclimatic Reconstruction Exposes Flaws in Climate Change Hypothesis

For a long time, the extinction of Homo neanderthalensis was attributed to Homo sapiens moving into their territories and extending their hunting activities to Neanderthals themselves. More recently a shift of perspective caused archaeologists to believe changes in climate brought about the demise of Neanderthals. But, after a detailed paleoclimatic reconstruction of the last ice age, which involved the analysis of stalagmites sampled from caves on the Murge karst plateau in Apulia, Italy, the new study concludes that this supposed climate change did not, in fact, occur in the western Mediterranean 42,000 years ago.

According to the research team, Neanderthals and Homo sapiens coexisted in this region for at least 3,000 years, from approximately 45,000 to 42,000 years ago. Samples extracted from stalagmites show that climate change, during this time span and in this area of Apulia, was “not particularly significant.” Andrea Columbu explains that this new research demonstrates a climate niche during the transition from Neanderthals to Homo sapiens, which leads to the conclusion that “it doesn't seem possible that significant climate changes caused the extinction of Neanderthals in Apulia”.

The field of paleoclimatic reconstruction based on stalagmite samples opens the door to a whole new world of discoveries and advances in understanding about the past. (Charles R. Knight / Public domain)

The field of paleoclimatic reconstruction based on stalagmite samples opens the door to a whole new world of discoveries and advances in understanding about the past. ( Charles R. Knight / Public domain )

Stalagmites as Paleoclimatic and Paleoenvironmental Archives

Thanks to what is the first ever paleoclimatic reconstruction of these early Neanderthal-occupied areas, the research team has managed to rebut the mainstream archaeological and paleontological hypothesis that claims that climate change was the cause of the demise of Neanderthals. The results gained from the analysis of stalagmite samples appear to prove that this thesis does not apply to the Neanderthals who inhabited the Mediterranean area as far back as 100,000 years ago.

Rising from the floor of Karst Caves , these stalagmites were formed over millions of years from drips of water from the cave ceiling. Jo De Waele, a research coordinator and professor at the University of Bologna, explains in Eureka Alert that stalagmites are “excellent paleoclimatic and paleoenvironmental archives” providing unquestionable evidence of the presence or absence of rain. The calcite in stalagmites is composed of carbon and oxygen isotopes which reveal soil conditions and how much it rained during their formation. When all this data had been assembled and interpreted with radiometric dating, the researchers discovered that Apulian stalagmites showed a consistent pace of dripping in the last and previous ice ages. This means, according to the paper, that “no abrupt change in climate happened during the millennia under investigation” that might have caused Neanderthals' extinction .

The question of what caused the demise of Neanderthals has been preoccupying scientists since the first Neanderthal remains were discovered in 1829 by the Dutch naturalist Philippe-Charles Schmerling in Belgium. (Thilo Parg / CC BY-SA 3.0)

The question of what caused the demise of Neanderthals has been preoccupying scientists since the first Neanderthal remains were discovered in 1829 by the Dutch naturalist Philippe-Charles Schmerling in Belgium. ( Thilo Parg / CC BY-SA 3.0 )

So, What Did Cause the Demise of Neanderthals?

The research concludes that there was little variation in rainfall between 50,000 and 27,000 years ago, while the carbon isotopes show that the bio-productivity of the soil samples remained consistent during this period. If climate change did not occur in this part of the Mediterranean, then scientists “may rule out” the hypothesis that it is responsible for the extinction of Neanderthals . So, if it wasn’t climate change , what caused the demise of Neanderthals after coexisting with Homo sapiens for about three thousand years?

Experts have been pondering the question of why Neanderthals became extinct since the beginnings of anthropology. When asked, Stefano Benazzi, a palaeontologist at the University of Bologna who is cited in the University of Bologna release , explains that the primary reason Homo sapiens achieved supremacy over Neanderthals “had to do with technology.” In other words, Homo sapiens developed new hunting technologies that were “far more advanced than Neanderthals” leading to the eventual extinction of our most notorious relatives.

Top image: Researchers have sampled an enormous stalagmite in the Pozzo Cucù cave in Italy in order to conduct paleoclimatic reconstruction of the last ice age. Their conclusions have helped answer questions related to the demise of Neanderthals. Source: O. Lacarbonara / University of Bologna

By Ashley Cowie

Comments

Lioba62's picture

The fact that Neanderthals and Homo sapiens existed together and we know by DNA that they mated. The integration of the two groups could also be part of the reason for the decline of the Neanderthals.

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