Climate Dynamics

, Volume 39, Issue 12, pp 2847–2866 | Cite as

The role of forcing and internal dynamics in explaining the “Medieval Climate Anomaly”

  • Hugues GoosseEmail author
  • Elisabeth Crespin
  • Svetlana Dubinkina
  • Marie-France Loutre
  • Michael E. Mann
  • Hans Renssen
  • Yoann Sallaz-Damaz
  • Drew Shindell


Proxy reconstructions suggest that peak global temperature during the past warm interval known as the Medieval Climate Anomaly (MCA, roughly 950–1250 AD) has been exceeded only during the most recent decades. To better understand the origin of this warm period, we use model simulations constrained by data assimilation establishing the spatial pattern of temperature changes that is most consistent with forcing estimates, model physics and the empirical information contained in paleoclimate proxy records. These numerical experiments demonstrate that the reconstructed spatial temperature pattern of the MCA can be explained by a simple thermodynamical response of the climate system to relatively weak changes in radiative forcing combined with a modification of the atmospheric circulation, displaying some similarities with the positive phase of the so-called Arctic Oscillation, and with northward shifts in the position of the Gulf Stream and Kuroshio currents. The mechanisms underlying the MCA are thus quite different from anthropogenic mechanisms responsible for modern global warming.


Paleoclimate Last millennium Medieval Climate Anomaly Climate modelling Data assimilation Atmospheric and ocean dynamics Radiative forcing 



We thank E. Zorita and R. Wilson for comments and all the scientists that collected and analysed the proxy data used in this work. H.G. is Senior Research Associate with the Fonds National de la Recherche Scientifique (FRS-FNRS-Belgium). This work is supported by the FRS-FNRS and by the Belgian Federal Science Policy Office (Research Program on Science for a Sustainable Development) and by EU (project Past4future). M.E.M. acknowledges support from the NSF Paleoclimate program (grant number ATM-0902133). Aurélien Mairesse helped in the design of Fig. 1. Computational resources have been provided by the supercomputing facilities of the Université Catholique de Louvain (CISM/UCL) and the Consortium des Equipements de Calcul Intensif en Fédération Wallonie Bruxelles (CECI) funded by the Fond de la Recherche Scientifique de Belgique (FRS-FNRS).


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Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • Hugues Goosse
    • 1
    Email author
  • Elisabeth Crespin
    • 1
  • Svetlana Dubinkina
    • 1
  • Marie-France Loutre
    • 1
  • Michael E. Mann
    • 2
  • Hans Renssen
    • 3
  • Yoann Sallaz-Damaz
    • 1
  • Drew Shindell
    • 4
  1. 1.Earth and Life Institute, Georges Lemaître Centre for Earth and Climate ResearchUniversité Catholique de LouvainLouvain-la-NeuveBelgium
  2. 2.Department of Meteorology and Earth and Environmental Systems InstitutePennsylvania State UniversityUniversity ParkUSA
  3. 3.Section Climate Change and Landscape Dynamics, Department of Earth SciencesVrije Universiteit AmsterdamAmsterdamThe Netherlands
  4. 4.NASA Goddard Institute for Space StudiesNew York CityUSA

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