Feedback mechanisms involving clouds, vegetation, sea ice, ice sheets, ocean circulation, and the carbon cycle substantially shaped the amplitude and timing of Quaternary deglaciations and the preceding glacial periods, as well as abrupt millennial-scale climate transitions during the last glacial period (the so-called Dansgaard–Oeschger, or (‘D-O’) events). Many uncertainties remain about the role of these feedbacks, and associated interactions between different earth system elements. This session will provide an opportunity to assess recent progress in documenting and understanding glacial-interglacial transitions and abrupt climate (including D-O events) events, and to evaluate the state of knowledge about model behaviour during these periods of major earth system change. We encourage studies based on climate proxy data, and those using numerical models to submit abstracts with the aim of facilitating a comprehensive overview of processes, feedbacks, and tipping points during glacials and deglaciations; and particularly welcome CMIP-PMIP-relevant contributions.