Public Release: 

Synchrony in human energy consumption

Proceedings of the National Academy of Sciences

Researchers report evidence of long-term synchronous energy consumption between human societies. Many species exhibit synchrony, or coincident changes in an attribute over space and time, between populations. Whether human societies exhibit synchrony is unclear; nor are the potential underlying mechanisms known. Jacob Freeman and colleagues analyzed historical and radiocarbon records to identify synchrony in energy consumption among human populations. The historical records provided information on energy consumption in eight countries since 1880, whereas radiocarbon records provided estimates of energy consumption in societies from four continents over the past 10,000 years. Energy consumption tended to oscillate at a similar rhythm across the various radiocarbon and historical records. The degree of rhythmic synchrony decreased with distance, with records from the same continent exhibiting greater synchrony than those from different continents. Long-term mean trends in energy consumption were also correlated across societies in both the radiocarbon and historical records. The decline in synchrony with distance suggests that synchrony in both ancient and modern societies is driven by interactions such as trade, migration, and conflict. The results further suggest that globalization may not be a new phenomenon, but instead a natural consequence of human societies evolving toward increased carrying capacity, according to the authors.

Article #18-02859: "Synchronization of energy consumption by human societies throughout the Holocene," by Jacob Freeman et al.

MEDIA CONTACT: Jacob Freeman, Utah State University, Logan, UT; tel: 435-797-5744, 515-556-6385; e-mail:


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