Centennial to millennial scale Holocene climate-deep water linkage in the North Atlantic

The stability of the Earth's climate is strongly linked to the steadiness of the atmospheric and oceanic transport of heat from low to high latitudes. High resolution Holocene sedimentary records from the subpolar North Atlantic demonstrate a persistent link between centennial to millennial scale fluctuations in the flow speed of Iceland-Scotland Overflow Water inferred from granulometric proxy data and both the surface North Atlantic Current component of the meridional overturning circulation (MOC) and published Fennoscandian atmospheric temperature variability. However, these data also highlight the difficulties associated with the interpretation of geochemical and sedimentological deep water circulation proxies as they do not provide a wholly consistent picture. The similarity between surface and deep ocean delta(13)C records suggests a preformed component in the deep ocean delta(13)C signal. On the other hand, the sedimentological results display a strong linkage to changing conditions in the overlying surface ocean waters, suggesting this proxy better reflects the activity of the MOC at least during the Holocene of this region. The most widespread oceanic perturbation coincides with an interval of possibly global climatic deterioration around 2700 years ago. These results firmly establish deep water production in the Nordic Seas as a key component in the assortment of variables affecting climate during the Holocene. (C) 2004 Elsevier Ltd. All rights reserved.