A global analysis of reconstructed land climate changes during Dansgaard-Oeschger events

Abstract. Dansgaard–Oeschger (D–O) warming events are comparable in magnitude and rate to the anticipated 21st century warming. As such, they provide a good target for evaluation of the ability of state-of-the-art climate models to simulate rapid climate changes. Despite the wealth of qualitative information about climate changes during the D-O events, there has been no attempt to date to make quantitative reconstructions globally. Here we provide reconstructions of seasonal temperature changes and changes in plant-available moisture across multiple D-O events during Marine Isotope Stage 3 based on available pollen records across the globe. These reconstructions show that the largest changes in temperature occurred in northern extratropics, especially Europe and Eurasia. The change in winter temperature was not significantly different from the change in summer temperature, and thus there is no evidence that the D-O events were characterised by a change in seasonality. Although broadscale features of the temperature changes were consistent across the eight D-O events examined, the spatial patterns of temperature changes vary between events. Globally, changes in moisture were positively correlated with changes in temperature, but the strength and the sign of this relationship vary regionally. These reconstructions can be used to evaluate the spatial patterns of changes in temperature and moisture in the transient simulations of the D-O events planned as part of the Palaeoclimate Modelling Intercomparison Project.