A recent study by scientist Jeff Morgan Stibel of the California Museum of Natural History has found a surprising link between climate change and the decline in human brain size.
Stibel analyzed the fossils of 298 specimens from the last 50,000 years, along with natural records of global temperature, humidity, and precipitation, to understand the impact of environmental changes on the neurological system and consequently on human behavior.
Stibel had previously analyzed brain shrinkage and sought to find the causes of this phenomenon.
The scientists divided the fossils into four groups based on their age at four different intervals: 100 years, 5,000 years, 10,000 years and 15,000 years. They then compared the observed changes in the samples to four different climate records.
“Given recent global warming trends, it is critical to understand the impact of climate change, if any, on human brain size and ultimately human behavior,” Stibel writes in his published paper.
The weather is not the only factor.
The study concluded that as temperatures have been increasing, the average size of the brain has been decreasing significantly.
However, this process occurs over multiple generations and takes thousands of years.
In particular, the size of the human brain shrank by 10.7% during the warm Holocene period. Humidity levels and precipitation also seem to influence brain growth, although to a lesser extent than temperature, according to the study.
Although Stibel comes to the conclusion that there is a link between climate change and the size of the human brain, he acknowledges that other factors also influence this phenomenon, such as the ecosystem, culture or technology.
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