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www.clim-past-discuss.net/7/2355/2011/
doi:10.5194/cpd-7-2355-2011
© Author(s) 2011. This work is distributed
under the Creative Commons Attribution 3.0 License.
Revisiting the humid Roman hypothesis: novel analyses depict oscillating patterns
1Utrecht University, Department of Environmental Sciences, Copernicus Institute, 3508 TC Utrecht, The Netherlands
2Utrecht University, Department of Physical Geography, 3508 TC Utrecht, The Netherlands
3Royal Netherlands Meteorological Institute (KNMI), 3730, AE, De Bilt, The Netherlands
Abstract. Previous studies have proposed that potential vegetation in the Mediterranean maintained a wetter climate during the Roman Period until the initiation of large scale deforestation. The reduction in evapotranspirative fluxes associated with deforestation is suggested to have caused climatic aridification leading to the establishment of the present-day Mediterranean climate. There is also evidence to indicate that during the Roman Period Mediterranean climate was influenced by low frequency fluctuations in sea level pressure over the North Atlantic, termed here: the Centennial North Atlantic Oscillation (CNAO). In order to understand the importance of each of these mechanisms and disentangle their respective signals in the proxy record, we have employed an interdisciplinary approach that exploits a range of tools and data sources. An analysis of archaeological site distribution and historical texts demonstrate that climate did not increase in aridity since the Roman Period. Using an Earth system model of intermediate complexity prescribed with a reconstruction of ancient deforestation, we find that Mediterranean climate was insensitive to deforestation in the Late Holocene. A novel analysis of a composite of proxy indicators of climatic humidity depicts spatial and temporal patterns consistent with the CNAO. The link between the CNAO during the Roman Period and climatic humidity signals manifest in our composite analysis are demonstrated using a modelling approach. Finally, we present evidence indicating that fluctuations in the CNAO contributed to triggering a societal tipping point in the Eastern Mediterranean at the end of the Roman Period.
Discussion Paper (PDF, 3373 KB) Supplement (17 KB) Interactive Discussion (Closed, 4 Comments) Final Revised Paper (CP)
Notice on Discussion StatusCitation: Dermody, B. J., de Boer, H. J., Bierkens, M. F. P., Weber, S. L., Wassen, M. J., and Dekker, S. C.: Revisiting the humid Roman hypothesis: novel analyses depict oscillating patterns, Clim. Past Discuss., 7, 2355-2389, doi:10.5194/cpd-7-2355-2011, 2011. Bibtex EndNote Reference Manager XML
