evidence: The ca. 1100-year-long cold period is typically explained by an abrupt shift to a weaker state of the Atlantic Meridional Overturning Circulation (AMOC)19,20,21,22 in combination with atmosphere–sea-ice–ocean feedbacks8,9. The reason for the abrupt slowdown of the AMOC has been attributed to the excess freshwater fluxes into the North Atlantic Ocean in response to melting ice sheets9,21,22. Coupled atmosphere–ocean models, simulating a strong AMOC reduction during the YD11,21,23,24,25,26, generally reproduce the winter-dominated annual cooling signal in Greenland ice cores4,27 but fail to reproduce the European summer cooling11,28. It was hence suggested that forcings other than the AMOC slowdown and the associated cooling of the North Atlantic Ocean are required to explain the YD such as a reduction in solar activity28, a change in wind patterns29 or ice sheets30,31, or possibly a combination of an AMOC slowdown with lower solar activity11. As evidence for such a ~1100-long negative forcing is lacking, the mechanisms and/or regional climatic impacts of the YD remain elusive. [...] Steffensen, J. P. et al. High-resolution greenland ice core data show abrupt climate change happens in few years. Science321, 680–684 (2008). [...] Rasmussen, S. O. et al. A new Greenland ice core chronology for the last glacial termination. J. Geophys. Res. Atmos.111, D06102 (2006).