The geological record provides insight into how climate and carbon cycle processes operate and evolve under different than modern boundary conditions and forcings. Understanding past climate evolution is paramount to progressing on understanding fundamental questions of Earth System feedbacks and sensitivity to perturbations, such as the behaviour of the climate system and carbon cycle under elevated atmospheric CO2 concentration—relative to the Quaternary—, or the existence of environmental tipping points and thresholds. In recent years, geochemical techniques and Earth System Models complexity have been greatly improved and several international projects on past climates (e.g., DeepMIP, MioMIP, PlioMIP) have been initiated within the wider PMIP, helping to bridge the gap between palaeoclimate modelling and data communities. This session invites work on past climates and carbon cycling across the Phanerozoic using model simulations and/or proxy-based reconstructions. We especially encourage submissions featuring reconstructions of palaeoenvironments or processes, palaeoclimate-ocean and carbon cycle modelling, and the integration of CO2 and (hydro)climate proxies with models of any complexity.