Global warming is expected to critically affect human society, economic growth and biodiversity. In order to better predict future changes of the climate system and to potentially develop adaptation and mitigation strategies, modern science has been looking back to the past to assess the feedback reactions of the global climate system under varying boundary conditions. However, incomplete understanding of the quantitative role of physical and biogeochemical mechanisms hinders comprehensive models to reliably simulate past climate variability, thereby hampering robust predictions of the future evolution of the climate system.The meridional overturning circulation of the oceans plays an instrumental role in modulating climate by storing and redistributing heat, salt, carbon and nutrients around the planet. This proposal focuses on investigating the interactions between climate and ocean circulation, as gleaned from the testimony of paleoceanographic records. These records extend beyond the noise of recent decadal oscillations, to provide an independent perspective on the links between climate and ocean dynamics.Former studies found significant re-organisations of ocean dynamics during the last glacial cycle, but were not able to provide robust, quantitative estimates of past changes in ocean circulation. This research proposal aims at providing transformational constraints on the role of the ocean in driving climate change. The innovative dimension of the proposed research resides in the combined approach involving cutting edge analytical techniques and state-of-the-art model simulations. The proposed research will provide unprecedented quantitative, large-scale estimates of past changes in ocean circulation enabling more reliable predictions of future climate change.