Freshwater (FW) forcing is widely identified as the dominant mechanism causing reductions of the Atlantic Meridional Overturning Circulation (AMOC), a climate tipping point that led to past abrupt millennial-scale climate changes. However, the AMOC response to FW forcing has not been rigorously assessed due to the lack of long-term AMOC observations and uncertainties of sea-level rise and ice-sheet melt needed to infer past FW forcing. Here we show a muted AMOC response to FW forcing (~50 m sea-level rise from the final deglaciation of Northern Hemisphere ice sheets) in the early-to-middle Holocene ~11,700–6,000 years ago. Including this muted AMOC response in a transient simulation of the Holocene with an ocean–atmosphere climate model improves the agreement between simulated and proxy temperatures of the past 21,000 years. This demonstrates that the AMOC may not be as sensitive to FW fluxes and Arctic freshening as is currently projected for the end of the twenty-first century.

淡水（FW）强迫被广泛认为是导致大西洋经向翻转环流（AMOC）减少的主要机制，这是一个导致过去千年级气候突然变化的气候临界点。然而，由于缺乏长期的 AMOC 观测以及推断过去 FW 强迫所需的海平面上升和冰盖融化的不确定性，AMOC 对 FW 强迫的响应尚未得到严格评估。在这里，我们展示了在约 11,700-6,000 年前的早至中期全新世中，AMOC 对 FW 强迫（从北半球冰盖的最终消冰期海平面上升约 50 m）的柔和响应。在海洋-大气气候模型的全新世瞬态模拟中包含这种柔和的 AMOC 响应，提高了过去 21,000 年模拟温度和代理温度之间的一致性。