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A scientist in the US has uncovered a potential effect of climate change that has been little-known until now. And it's surprising, to say the least. According to this research, the human brain could shrink as a result of climate disruption.
A scientist in the US has uncovered a potential effect of climate change that has been little-known until now. And it's surprising, to say the least. According to this research, the human brain could shrink as a result of climate disruption.
To reach this conclusion, scientist Jeff Morgan Stibel, a researcher at the National History Museum in Los Angeles, analyzed the brain fossils of 298 Homo specimens to assess possible changes in their size linked to the impact of climatic variations (changes in temperature, rainfall, humidity, drought, etc.) over the last 50,000 years. Published in the journal Brain, Behavior and Evolution, the study is based on data relating to the geographical origin of Homo specimens, as well as their sex. Once this information had been collated, brain size was studied in relation to several ice ages.
The study concluded that brain size had decreased by around 10.7% during the Holocene warming period, an ongoing geological era that began over 11,000 years ago. "Across regional and global paleoclimate records, brain size in Homo averaged significantly lower during periods of climate warming as compared to cooler periods," Jeff Morgan Stibel explains. "The results suggest that climate change is predictive of Homo brain size, and certain evolutionary changes to the brain may be a response to environmental stress," the scientist observes.
To a lesser extent, arid periods were associated with larger brain size, compared with periods of humidity and precipitation. Temperature variations therefore appear to be the more important climatic factor in brain size change. "The adaptive response appears to have started roughly 15,000 years ago and may persist into modern times," explains Jeff Morgan Stibel.
However, the researcher points out that "future studies will be needed to confirm any assumptions regarding the responsiveness of brain size to climate change." Indeed, these findings should be treated with caution, especially as other factors unrelated to climate, such as culture and technology, could also influence changes in human brain size.
