The Atlantic Meridional Overturning Circulation (MOC) carries warm water northward in surface layers with compensating southward flow at depth. Associated with this overturning is a northward heat transport. It is widely (though not universally) accepted that this heat transport makes a substantial contribution to the moderate climate of maritime and continental Europe, and that any slowdown in the overturning circulation has a profound impact on global climate. In this proposal we focus on reconstructing and modeling anomaly patterns of temperature, radiocarbon concentration (δ¹⁴C), and stable oxygen and carbon isotope ratios in tropical/subtropical upper ocean waters of the Atlantic for rapid climate events during the past 15,000 years that are evidently related to reduced MOC: the Younger Dryas cold period and the so-called “8.2-kyr” and “4.2-kyr” events. Especially the 8.2-kyr event which occurred under near-modern climate conditions will help in estimating limits on climate anomalies that might result from a possible future slowdown of the Atlantic MOC in response to continued global warming and an intensification of the hydrological cycle. Moreover we plan to determine the decadal-to-centennial-scale variability of upper ocean water properties. The DAMOCLES project will combine paleo-proxy data with climate model studies in order to advance our understanding with regard to those key questions formulated in the INTERDYNAMIC proposal that address: (1) amplitudes of natural Holocene climate variability, (2) temporal and spatial changes in patterns of climate variability, and (3) abrupt shifts in the Atlantic large-scale ocean circulation during interglacials.

Quantitative paleo-temperature reconstructions, surface-to-intermediate water radiocarbon gradients, coupled climate modelling

 

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