Fig. 4: Millennium-scale changes in ACC strength compared to paleoclimatic records over the last 60 ka.

a Oxygen isotope record from North Greenland Ice Core Project (NGRIP, δ18O vs. VSMOW)70. b Bermuda Rise 231Pa/230Th proxy for the AMOC strength44,59,60. c Saturation index as a proxy for reconstructed carbonate saturation changes in the South Atlantic49. d \(\overline{{{{\rm{SSFS}}}}}\) as flow speed proxies for the current strength (three-point smoothing, this study) and the transferred ACC flow speeds. e Relative abundance of diatom winter sea ice indicator Fragilariopsis curta group (F. curta + F. cylindrus) with three-point smoothing22,67. The group abundance >3% indicates the presence of winter sea ice22,67. f Synchronized ice-core atmospheric pCO245. g δ18O time series from the EDML ice core45. Vertical gray bars mark inferred millennial-scale ACC peaks that correspond with millennial-scale temperature maxima in Antarctica (AIM) and Heinrich events (H) in Greenland.