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

Published

Journal Article

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. © 2012 Springer-Verlag.

Full Text

Duke Authors

Cited Authors

  • Goosse, H; Crespin, E; Dubinkina, S; Loutre, MF; Mann, ME; Renssen, H; Sallaz-Damaz, Y; Shindell, D

Published Date

  • November 1, 2012

Published In

Volume / Issue

  • 39 / 12

Start / End Page

  • 2847 - 2866

Electronic International Standard Serial Number (EISSN)

  • 1432-0894

International Standard Serial Number (ISSN)

  • 0930-7575

Digital Object Identifier (DOI)

  • 10.1007/s00382-012-1297-0

Citation Source

  • Scopus