A recent study by scientist Jeff Morgan Stibel at the California Museum of Natural History discovered a surprising link between climate change and the decline in human brain size.
Stibel analyzed the fossils of 298 specimens from the past 50,000 years, along with natural records of temperature, humidity and global precipitation, to understand the impact of environmental changes on the neurological system and because of this in human behavior. Stibel has previously investigated brain shrinkage and sought the causes of this phenomenon.
Scientists divide the fossils into four groups based on their age in four different intervals: 100 years, 5,000 years, 10,000 years and 15,000 years. They then compared the changes observed in the samples with four different climate records.
“Given recent global warming trends, it is important to understand the impact of climate change, if any, on human brain size and, ultimately, human behavior,” wrote Stibel in his published paper.
Climate is not the only factor
The study concluded that as the temperature increased, the average brain size decreased significantly. However, this process takes place over many generations and takes thousands of years.
In particular, human brain size decreased by 10.7% during the Holocene warming. Humidity levels and rainfall also seem to influence brain development, although less so than temperature, according to the study.
Although Stibel concluded that there is a link between climate change and the size of the human brain, he acknowledged that other factors also influence this phenomenon, such as ecosystems, culture or technology.