To what extent was the Little Ice Age a result of change in the thermohaline circulation?

For a full understanding of the global climate system, it is imperative to integrate research on empirical climate reconstruction with physical modelling studies of the Earths climate, using numerical models of varying complexity to address important questions about the attribution of past and future climate changes to specific natural and anthropogenic factors. The focus of this project is on testing various hypotheses about the possible causes of the Little Ice Age. A carefully-designed set of model experiments (incorporating novel methods of assimilating information on climate time scales) is proposed, with the outputs assessed through comparison against empirical palaeoclimate evidence for climate variations over the past millennium. Specifically, we will explore whether the Little Ice Age climate could have been generated by one or more of the following factors: a weakening of the Atlantic thermohaline circulation; the persistence of a generally negative North Atlan tic Oscillation; or reduced radiat ive forcing (by increased volcanic activity, reduced solar insolation and lower greenhouse gas concentrations relative to the present). The proposed project will involve a 3-year collaboration between the University of East Anglia (UK) and the Royal Netherlands Meteorological Institute (Netherlands).