Samuli Helama et al., Multicentennial megadrought in northern Europe coincided with a global ENSO drought pattern during the Medieval Climate Anomaly

Geology, February 2009, Vol. 37, No. 2, 175–178; doi:10.1130/G25329A.1
© 2009 Geological Society of America

Multicentennial megadrought in northern Europe coincided with a global El Niño–Southern Oscillation drought pattern during the Medieval Climate Anomaly

Samuli Helama¹, Jouko Meriläinen² and Heikki Tuomenvirta³

¹Department of Geology, P. O. Box 64, 00014 University of Helsinki, 00014 Helsinki, Finland
²SAIMA Unit of Savonlinna Department of Teacher Education, University of Joensuu, P. O. Box 86, 57101 Savonlinna, Finland
³Finnish Meteorological Institute, P. O. Box 503, 00101 Helsinki, Finland

Abstract

The El Niño–Southern Oscillation (ENSO) is a pacemaker of global climate, and the accurate prediction of future climate change requires an understanding of the ENSO variability. Recently, much-debated aspects of the ENSO have included its long-term past and future changes and its associations with the North Atlantic and European sectors, potentially in interaction with the North Atlantic Oscillation and the Atlantic Multidecadal Oscillation. Here we present the first European dendroclimatic precipitation reconstruction that extends through the alternating climate phases of the Medieval Climate Anomaly and the Little Ice Age. We show that northern Europe underwent a severe precipitation deficit during the Medieval Climate Anomaly, which was synchronous with droughts in various ENSO-sensitive regions worldwide, while the subsequent centuries during the Little Ice Age were markedly wetter. We attribute this drought primarily to an interaction between the ENSO and the North Atlantic Oscillation, and to a lesser (or negligible) degree to an interaction between the ENSO and the Atlantic Multidecadal Oscillation.

Link to abstract: http://geology.gsapubs.org/cgi/content/abstract/37/2/175