Evidence for centennial scale sea level variability during the Medieval Climate Optimum (Crusader Period) in Israel, eastern Mediterranean

E. Toker, D. Sivan, E. Stern, B. Shirman, M. Tsimplis, G. Spada

Research output: Contribution to journalArticlepeer-review


The current study provides evidence supporting a sea-level drop of up to about 50 ± 20. cm at the eastern coasts of the Mediterranean basin during the period AD 900-1300. The estimate is based on a variety of archaeological remains, mostly from the Crusader period, compared with other archaeological and biological proxies of sea level from the periods before and after.The Crusader low levels overlap the period known as the 'Medieval Warm Period' (MWP) or the 'Medieval Climate Anomaly' (MCA). On the basis of published data it appears that a positive North Atlantic Oscillation (NAO) phase coincided with a negative Southern Oscillation Index (SOI), the former affecting the temperature and freshwater flux in the Mediterranean Sea and most of its rivers, and the latter affecting the Nile outflow. Changes of 0.125. psu in salinity and 0.4 °C are estimated as upper limits for the change, and these are expected to cause a sea-level drop consistent in magnitude with the observed values. These provide the upper limit for a regional climate-forcing attribution of the observed sea level low. The possibility of crustal uplifts contributing to the observed changes is also discussed.

Original languageEnglish
Pages (from-to)51-61
Number of pages11
JournalEarth and Planetary Science Letters
StatePublished - 15 Jan 2012

Bibliographical note

Funding Information:
The authors would like to thank the Sir Maurice and Lady Hatter Fund of the Leon Recanati Institute for Maritime Studies (RIMS), University of Haifa , for supporting Eilat Toker's study, the data and results of which are the core of the current paper. Many thanks are also due to Shalom Yankelevich, Dani Doron, Yoram Efrat and Dani Sion for the unpublished data. We also wish to mention that this work was partly supported by COST Action ES0701 “Improved Constraints on Models of Glacial Isostatic Adjustment” . Special thanks are due to Prof. R. Gehrels, Geography Department of Plymouth University, UK, where this paper was written, for inviting Dr. D. Sivan (corresponding author) to spend her sabbatical leave there. We would like to express our appreciation and to thank the reviewers for their thoughtful and challenging remarks, and also to thank Dr. Guy Woppelmann, LIENSS, UMR 6250 Université de La Rochelle for the GPS consultation. Thanks are also due to N. Yoselevich for the figures, and to J. B. Tresman for the editorial review.


  • Archaeological sea-level indications
  • East Mediterranean
  • Medieval Climate Anomaly (MCA)
  • Positive NAO conditions
  • Sea-level

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science


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