Abstract
Aim
The long‐term cyclical patterns of China's geopolitical shifts are of great interest to scholars and the public, but to date there has been no satisfactory explanation for the alternating occupancy patterns of the country's pastoral and agrarian polities. We fill this gap by differentiating the agroecological settings of these polities over time and quantitatively analysing the relationships between climate change and historical geopolitical variations.
Location
China.
Methods
Our dataset comprised 38 palaeohydroclimate reconstructions, the historical boundaries of China's empire and the changes in its size, and 1028 wars and 2737 battle locations over the past 2300 years. China‐wide precipitation during the period was reconstructed using the ‘weighted composite plus scale’ method. Time‐series analyses were performed to identify the strength of the associations between climate change and the geopolitical variables. Granger causality analysis and wavelet analysis were performed to verify the hypothesized causal links. Wavelet analysis was also used to identify the possible interactions (i.e. frequencies, significance, consistency and synchrony) between the signal components of the climatic and geopolitical variables at different temporal scales.
Results
China's mean precipitation fell into three multicentennial cycles. The geopolitical variables corresponded to those cycles in the imperial era. The spatial–temporal frequencies of the boundaries and size of the agriculturalist empires and its frontiers with pastoralist empires were regulated by the long‐term (low‐frequency) precipitation fluctuations at the multicentennial scale. Wars of aggression were an important explanatory factor driving the land‐occupancy patterns of the two ecoempires under climate change, and caused most of the territorial shifts. Short‐term (high‐frequency) geopolitical changes were not associated with climate change.
Main conclusions
Precipitation‐induced ecological change was an important factor governing the macrogeopolitical cycles in imperial China. Long‐term territorial expansion favoured the polity (agriculturalist or pastoralist) that was better adapted to the changing ecological conditions in the country's heartland. Copyright © 2014 The Authors. Global Ecology and Biogeography published by John Wiley & Sons Ltd.
The long‐term cyclical patterns of China's geopolitical shifts are of great interest to scholars and the public, but to date there has been no satisfactory explanation for the alternating occupancy patterns of the country's pastoral and agrarian polities. We fill this gap by differentiating the agroecological settings of these polities over time and quantitatively analysing the relationships between climate change and historical geopolitical variations.
Location
China.
Methods
Our dataset comprised 38 palaeohydroclimate reconstructions, the historical boundaries of China's empire and the changes in its size, and 1028 wars and 2737 battle locations over the past 2300 years. China‐wide precipitation during the period was reconstructed using the ‘weighted composite plus scale’ method. Time‐series analyses were performed to identify the strength of the associations between climate change and the geopolitical variables. Granger causality analysis and wavelet analysis were performed to verify the hypothesized causal links. Wavelet analysis was also used to identify the possible interactions (i.e. frequencies, significance, consistency and synchrony) between the signal components of the climatic and geopolitical variables at different temporal scales.
Results
China's mean precipitation fell into three multicentennial cycles. The geopolitical variables corresponded to those cycles in the imperial era. The spatial–temporal frequencies of the boundaries and size of the agriculturalist empires and its frontiers with pastoralist empires were regulated by the long‐term (low‐frequency) precipitation fluctuations at the multicentennial scale. Wars of aggression were an important explanatory factor driving the land‐occupancy patterns of the two ecoempires under climate change, and caused most of the territorial shifts. Short‐term (high‐frequency) geopolitical changes were not associated with climate change.
Main conclusions
Precipitation‐induced ecological change was an important factor governing the macrogeopolitical cycles in imperial China. Long‐term territorial expansion favoured the polity (agriculturalist or pastoralist) that was better adapted to the changing ecological conditions in the country's heartland. Copyright © 2014 The Authors. Global Ecology and Biogeography published by John Wiley & Sons Ltd.
| Original language | English |
|---|---|
| Pages (from-to) | 87-96 |
| Journal | Global Ecology and Biogeography |
| Volume | 24 |
| Issue number | 1 |
| Early online date | 23 Oct 2014 |
| DOIs | |
| Publication status | Published - Jan 2015 |
Citation
Zhang, D. D., Pei, Q., Lee, H. F., Zhang, J., Chang, C. Q., Li, B., Li, J., & Zhang, X. (2015). The pulse of imperial China: A quantitative analysis of long-term geopolitical and climatic cycles. Global Ecology and Biogeography, 24 (1), 87-96. doi: 10.1111/geb.12247 .Keywords
- Agroecology
- Climate change
- Geopolitical boundary
- Granger causality analysis
- Empire size
- Imperial China
- Precipitation
- War
- Wavelet analysis