Regional seesaw between the North Atlantic and Nordic Seas during the last glacial abrupt climate events

• Published in: Climate of the Past
• Main Authors: Wary, Melanie, Eynaud, Frederique, Swingedouw, Didier, Masson-delmotte, Valerie, Matthiessen, Jens, Kissel, Catherine, Zumaque, Jena, Rossignol, Linda, Jouzel, Jean
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Gesellschaft Mbh 2017
• Subjects: Greenland; Norwegian Sea; Nordic Seas; North Atlantic; Northeast Atlantic; Sea ice
• Online Access: https://archimer.ifremer.fr/doc/00420/53149/55328.pdf; https://archimer.ifremer.fr/doc/00420/53149/55329.pdf; https://doi.org/10.5194/cp-13-729-2017; https://archimer.ifremer.fr/doc/00420/53149/

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.