How Neolithic man adapted to climate change
New research shows how early farmers adapted to a well-documented climate shift 8,200 years ago. The results demonstrate the value of using lipid biomarkers to explore ancient societies’ responses to climate change.
A new study led by the University of Bristol and co-authored by a Stanford University researcher has uncovered evidence that early farmers adapted to climate change 8,200 years ago.
The research, published Aug. 13 in the Proceedings of the National Academy of Sciences (PNAS), centered on the Neolithic and Chalcolithic city settlement of Çatalhöyük in southern Anatolia, Turkey, which existed from about 7500 BC to 5700 BC. During the height of the city’s occupation, a well-documented climate change event 8,200 years ago resulted in a sudden decrease in global temperatures caused by the release of a large amount of glacial meltwater from a massive freshwater lake in northern Canada.
This was the first time this climate event had ever been linked to an archaeological site.
Examining the animal bones excavated at the site, scientists concluded that the city’s herders turned toward sheep and goats at this time, as these animals were more drought-resistant than cattle. Cut marks on the animal bones revealed butchery practices: a high number of marks during the climate event showed that the population exploited any available meat due to food scarcity.
“By linking past climate change to archaeological records, this research allows us to more closely explore changes in human behavior concurrent with past environmental change,” said co-author Sharmini Pitter, PhD ’14, who conducted isotopic analyses for the paper as part of her dissertation in the department of Environmental Earth System Science at the School of Earth, Energy & Environmental Sciences.
The authors also examined the animal fats surviving in ancient cooking pots. They detected the presence of ruminant carcass fats, consistent with the animal bone assemblage discovered at Çatalhöyük. For the first time, compounds from animal fats detected in pottery were shown to carry evidence for the climate event in their isotopic composition.
“This was the first time this climate event had ever been linked to an archaeological site,” said Pitter, who currently serves as the Assistant Director of the NOAA Center for Coastal and Marine Ecosystems (CCME) at Florida A&M University.
The scientists concluded that the isotopic information carried in the hydrogen atoms from the animal fats reflected that of an ancient precipitation. A change in the hydrogen signal suggested changes in precipitation patterns corresponding to the shift to cold and dry conditions.
“Changes in precipitation patterns in the past are traditionally obtained using ocean or lake sediment cores,” said lead author Mélanie Roffet-Salque of the University of Bristol. “This opens up a completely new avenue of investigation – the reconstruction of past climate at the very location where people lived using pottery.”
Co-authors of the paper include Paul Valdes and Richard Evershed of the University of Bristol; Arkadiusz Marciniak, Kamilla Pawłowska, and Marta Krüger of Adam Mickiewicz University; Joanna Pyzel and Lech Czerniak of the University of Gdansk; and C. Neil Roberts of Plymouth University.