Co-ordinated shifts in deep-water formation and Gulf Stream migration during abrupt climate changes

Article https://doi.org/10.1038/s41467-026-73832-4 Co-ordinated shifts in deep-water formation and Gulf Stream migration during abrupt climate changes Received: 26 September 2025 6 , Check for updates 1234567890():,; 1234567890():,; Accepted: 18 May 2026 Fangjingcheng Zhu(朱方敬诚) 1,10 , Alice Carter-Champion1,2, Jack H. Wharton 1, Joel Bracamontes-Ramírez 3, Andrea Burke 4, Peter B. de Menocal5, David Fairman1, Lloyd D. Keigwin5, Thomas M. Marchitto Eirini Papachristopoulou1, James W. B. Rae 4, Yair Rosenthal 7,8, Ning Zhao(赵宁) 9 & David J. R. Thornalley 1,5 Theory and models suggest the Gulf Stream may shift northwards under projected Atlantic Meridional Overturning Circulation weakening. Yet Gulf Stream behaviour during past abrupt cold events remains poorly constrained. Here we present high-resolution paleoceanographic records from the Northwest Atlantic during the last deglaciation. During the Younger Dryas cold period, we document a northward Gulf Stream shift evidenced from coherent surface and subsurface warming. Our sortable silt data suggest a strengthening of upper North Atlantic Deep Water that opposes weakening lower North Atlantic Deep Water, consistent with a seesaw feedback between the Nordic overflows and subpolar gyre. Our results constrain a co-ordinated sequence at the Younger Dryas onset: initial lower North Atlantic Deep Water weakening and subpolar sea‑ice expansion, lagged (58 ± 38 yr) by an increase in upper North Atlantic Deep Water and an eventual atmospheric reorganization (84 ± 51 yr after onset). These findings provide empirical support for model projections of future Gulf Stream shifts. The Atlantic Meridional Overturning Circulation (AMOC), comprising northward transport of warm surface water and southward return flow of cold North Atlantic Deep Water (NADW), plays a key role in redistributing heat, salt and nutrients in the climate system1. Today, NADW is composed of two distinct sources2: upper NADW (u-NADW) formed in the subpolar North Atlantic and lower NADW (l-NADW) formed by the two main overflows of Nordic Seas-derived waters across the Greenland-Scotland Ridge. Another key component of the North Atlantic circulation is the horizontal gyre circulation, composed of an anticyclonic subtropical gyre and a quasi-cyclonic subpolar gyre (SPG), both of which are important for meridional ocean heat transport3 and the densification of North Atlantic waters upon their transformation to NADW4. The vertical overturning and horizontal gyre circulation systems meet in the Northwest Atlantic, known as the pacemaker region for AMOC variability1. This region not only marks the boundary between the subtropical gyre and SPG, where the warm Gulf Stream meets the cold Labrador Current, but also where the southward-flowing Deep Western Boundary Current, a 1 Department of Geography, University College London, London, UK. 2Centre for Quaternary Research, Department of Geography, Royal Holloway, University of London, London, UK. 3Department of Earth System Sciences, University of Hamburg, Hamburg, Germany. 4School of Earth and Environmental Sciences, University of St Andrews, St Andrews, UK. 5Woods Hole Oceanographic Institution, Woods Hole, MA, USA. 6Department of Geological Sciences and INSTAAR, University of Colorado, Boulder, CO, USA. 7Department of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ, USA. 8Department of Earth and Planetary Sciences, Rutgers University, New Brunswick, NJ, USA. 9State Key Laboratory of Estuarine and Coastal Research and School of Marine Sciences, East China Normal University, Shanghai, China. 10Present address: School of Ocean and Earth Science, University of Southampton, Waterfront Campus, e-mail: ; National Oceanography Centre, Southampton, UK. Nature Communications | (2026)17:4966 1 Article https://doi.org/10.1038/s41467-026-73832-4 major conduit for exporting NADW, crosses underneath the Gulf Stream (Fig. 1a). Under anthropogenic climate change, the Northwest Atlantic is warming at a rate significantly faster than the global average5, whilst a parallel cooling trend occurs in the subpolar North Atlantic6, forming a dipole pattern in sea surface temperature (SST)7. Modelling studies have attributed the dipole pattern to a northward shift in the Gulf Stream (causing the warming in the Northwest Atlantic) and a reduced northward ocean heat transport (linked to the cooling in the central subpolar North Atlantic), both linked to a slowdown of the AMOC8,9, whose current state has been suggested to be the weakest in the past millennium10,11. Furthermore, the AMOC may be subject to substantial weakening in the future12,13, potentially leading to abrupt changes partially analogous to rapid climate oscillations observed during the last glacial period14,15. However, the behaviour of the Gulf Stream location during these past abrupt climate events remains poorly studied due to the absence of high-quality records in this region. In addition, although previous studies have suggested a reorganisation in NADW during past abrupt climate change16–18, the relationship between changes in u-NADW and l-NADW and the position of the Gulf Stream in the Northwest Atlantic is not well constrained. Here we use three marine sediment cores with sub-centennial resolution (Fig. 1; KNR197-10-44GGC, 43°21.01’ N, 60°12.48’ W, 966 m, hereafter 44GGC; KNR158-4-09GGC, 44°49.60’ N, 54°53.78’ W, 1854 m, hereafter 09GGC; HU87003-7PC, 43°20.70’ N, 60°12.90’ W, 920 m) to study the paleoceanographic changes in the Northwest Atlantic prior to, and during, the Younger Dryas (YD), which marks an abrupt return from the warm Bølling–Allerød (BA) to near-glacial conditions in the North Atlantic region during the last deglaciation19. Today, these sites are located on the shoreward, northern side of the Gulf Stream (Fig. 1a) and are bathed at depth by u-NADW20 (Fig. 1c, d and Supplementary Fig. 1). Our records were synchronised with the Greenland ice core chronology21 (Methods; Fig. 2) by correlating the ice-rafted detritus (IRD) with the North Greenland Ice Core Project (NGRIP) Ca2+ (a proxy for dust)21, based on the assumption that the centennial- and millennial-scale IRD deposition events are associated with nearsynchronous iceberg discharges from circum-North Atlantic ice sheets, controlled by rapid climatic/atmospheric oscillations22–26. The robustness of our age model is supported by the synchronisation of the Vedde Ash layer (Methods; Supplementary Fig. 2), and the agreement of our surface 14C reservoir ages (derived from combining planktic foraminiferal 14C dates with our Tuned age model) and the regional high-latitude North Atlantic reservoir age stack27 (Fig. 2). In this article, we first reconstruct the deglacial changes in the strength of u-NADW using sortable silt grain size (SS), an established proxy for flow speed28–30. We then study the surface and subsurface temperature changes in the Northwest Atlantic and explore potentia (...truncated)