The MOC's impact on Scandinavia.
The cold Younger Dryas (YD) came to an abrupt end 11,700 years BP. And abrupt it was, air temperatures over Greenland rose some 15°C and precipitation doubled in roughly a decade, an incredibly rapid change in climate of the region. It is generally accepted that the heat and moisture must have come from a warm North Atlantic. In an earlier post (Aug. 16, 2024) I suggested that this reflected the rapid reorganization of the circulation from a principally wind-driven zonal flow across the ocean (paleo-Gulf Stream) to its present inclusion of warm water transport into the subpolar North Atlantic, and most importantly into the Nordic Seas for only here can one produce water dense enough to flow back into the deep North Atlantic and continue unrestricted south into the global abyssal ocean.
The sudden inflow of warm water and hence a warm atmosphere toward Scandinavia accelerated melting of the European ice masses, a process that had already started at the Bølling-Allerød transition 14,700 BP. Even though it would take several thousand years to melt the remain ice masses, the presence of warm water created a fertile coastal zone to hunters and gatherers. There is archeological evidence of human presence in southern Sweden 11,300 years ago, i.e. within a few hundred years of the end of the YD (Manninen et al., 2021). These peoples worked their way north along the Norwegian coast. There, they met another group coming around the continental ice from the north across Russia and Finland. The point is that thanks to the warm water inflow into the Norwegian and Barents Seas the coastal regions all around Scandinavia became fertile grounds for colonization.
As an aside, this program from Swedish television gives the viewer an idea of what science thinks about the first colonization of Scandinavia. Although no English subtitles, thanks to the excellent cinematography it is not difficult to get the gist of the program, I recommend it highly. https://www.svtplay.se/video/jQ76kE5/historien-om-sverige/1-stenaldern-ca-14-500-3700-ar-sedan?video=visa
While the Scandinavian ice mass was huge, its melting over 1000s of years led only to a modest freshwater flow into the Atlantic, much of it via the paleo-Baltic. This fresh-to-brackish water flowed into Skagerrak (as run-off does today) and continued north along the Norwegian coast into the Barents Sea making little contact with the warm salty waters farther offshore. It was no threat to the meridional overturning of the Nordic Seas.
Manninen, M.A., H. Damlien, J. I. Kleppe, K. Knutsson, A. Murashkin, A. R. Niemi, C. S. Rosenvinge and P. Persson (2021). First encounters in the north: cultural diversity and gene flow in Early Mesolithic Scandinavia. Antiquity, 95(380), 310-328.
DOI: https://doi.org/10.15184/aqy.2020.252