Persistent Positive North Atlantic Oscillation Mode Dominated the Medieval Climate Anomaly

Research output: Contribution to journalArticle


  • V Trouet
  • J Esper
  • NE Graham
  • JD Scourse
  • DC Frank

Colleges, School and Institutes


The Medieval Climate Anomaly (MCA) was the most recent pre-industrial era warm interval of European climate, yet its driving mechanisms remain uncertain. We present here a 947-year-long multidecadal North Atlantic Oscillation (NAO) reconstruction and find a persistent positive NAO during the MCA. Supplementary reconstructions based on climate model results and proxy data indicate a clear shift to weaker NAO conditions into the Little Ice Age (LIA). Globally distributed proxy data suggest that this NAO shift is one aspect of a global MCA-LIA climate transition that probably was coupled to prevailing La Nina-like conditions amplified by an intensified Atlantic meridional overturning circulation during the MCA.


Original languageEnglish
Pages (from-to)78-80
Number of pages3
Issue number5923
Publication statusPublished - 1 Apr 2009