Regional seesaw between the North Atlantic and Nordic Seas during the last glacial abrupt climate events
- 1UMR 5805, EPOC (Environnements et Paléoenvironnements Océaniques et Continentaux), CNRS-EPHE-Université de Bordeaux, 33615 Pessac, France
- 2UMR8212, LSCE (Laboratoire des Sciences du Climat et de l'Environnement)/IPSL (Institut Pierre Simon Laplace), CEA/CNRS-INSU/UVSQ, 91191 Gif-sur-Yvette CEDEX, France
- 3AWI (Alfred Wegener Institute), Helmholtz Centre for Polar and Marine Research, 27568 Bremerhaven, Germany
- anow at: GEOTOP, UQAM, Montréal, Québec H3C 3P8, Canada
Abstract. Dansgaard–Oeschger oscillations constitute one of the most enigmatic features of the last glacial cycle. Their cold atmospheric phases have been commonly associated with cold sea-surface temperatures and expansion of sea ice in the North Atlantic and adjacent seas. Here, based on dinocyst analyses from the 48–30 ka interval of four sediment cores from the northern Northeast Atlantic and southern Norwegian Sea, we provide direct and quantitative evidence of a regional paradoxical seesaw pattern: cold Greenland and North Atlantic phases coincide with warmer sea-surface conditions and shorter seasonal sea-ice cover durations in the Norwegian Sea as compared to warm phases. Combined with additional palaeorecords and multi-model hosing simulations, our results suggest that during cold Greenland phases, reduced Atlantic meridional overturning circulation and cold North Atlantic sea-surface conditions were accompanied by the subsurface propagation of warm Atlantic waters that re-emerged in the Nordic Seas and provided moisture towards Greenland summit.