“Contrary to the idea that early societies passively accepted environmental changes, our study shows that they developed sophisticated strategies to adapt to changing conditions,” says Dr. Magdalena Bunbury, the study’s lead author. The study uses, among other things, carbon isotope analysis (14C data) to date traces of human activity in the research area. The authors collected more than 20,000 14C data spanning the past 17,000 years. After strict quality control, 6268 data points remained that could be used for the study. “Using several statistical approaches, we can use these 14C data to reconstruct whether the population increased or decreased in certain eras,” explains Dr. Bunbury.
“In addition, we analyzed 49 high-resolution climate archives from the area between 50 and 70 degrees north latitude, which enable a detailed reconstruction of the environmental conditions in the study region between 4100 and 1100 BCE,” adds Dr. Mara Weinelt from the ROOTS Cluster of Excellence, who initiated and supervised the study. In addition, the team included archaeological information on more than 3,600 houses from nearly 1,500 sites across most of the study area.
Based on this extensive data set, the study’s results highlight the complex links between regional climate trends and local adaptations. For example, a pronounced Holocene warm period between around 7050 and 2050 BCE in Scandinavia had different effects depending on latitude. “In southern Scandinavia, this warmer climate may have encouraged the spread of agriculture in the early 4th millennium BC, which was accompanied by significant population growth,” says Dr. Bunbury, who conducted postdoctoral research at ROOTS until 2022 and is now at James Cook University in Cairns, Australia.
A cooling trend around 2250 BCE then marked the beginning of a climate shift. However, it varied in terms of duration and timing in the different latitudes and regions of the study area. Neolithic communities in southern Norway demonstrated their resilience despite cooling trends by continuing to farm and settle further in the region. At the same time, people in modern-day Denmark grew a greater variety of crops and developed houses in which crops could be stored for longer periods. “These processes can be interpreted as adaptations to the changed environmental conditions,” explains co-author Dr. Jutta Kneisel from the CAU.
A very special approach emerged in the icy expanses of Arctic Norway. Instead of adopting extensive farming as a livelihood, communities there continued to gather food from nature to ensure survival. With the wide range of food sources, they reduced risks.
The study also covers the 2nd millennium BCE and then shows abrupt cooling periods. The data indicate simultaneous short-term declines in population numbers. Archaeological finds suggest that trade networks with continental Europe were disrupted. After these short-term cooling phases, the population began to grow again from the middle of the 2nd millennium. She even developed a new, stable house shape.
“We cannot attribute all changes in human societies to climate. However, the data clearly shows significant connections between population trends, settlement and economic practices on the one hand, and climate trends on the other. In particular, the recovery of population numbers after abrupt “Cooling events in the 2nd millennium BCE are a clear indication of the resilience and adaptability of early societies in Scandinavia to climate fluctuations,” says Dr. Cries.
Further research focusing on smaller regions could provide further insight into the connections between people and the environment.