There is widespread recognition of the connectivity of different components of the Earth system, but many of these connections have not been studied. This is certainly true of connections between climate and the solid Earth. A thorough understanding of the climatic variations recorded in the geologic record cannot be obtained by studying climate in isolation from the solid Earth, and a complete understanding of the volcanic record requires consideration of the effects of climate variation. This is a proposal to investigate the coupling between climate and the solid Earth, and hence to better understand climate history and its impact on volcanism. The proposed work will use computational models of two-phase magma/mantle dynamics and petrology to explore links between glacial cycles and mid-ocean ridge volcanism. Glacial cycles redistribute water between the oceans and continents, changing sea level and hence varying the load on mid-ocean ridges. Melting beneath ridges responds to pressure changes, and should produce observable variation in crustal thickness and concentration of incompatible elements. Carbon dioxide is one such incompatible element, and pressure-induced variations in out-gassing rate from the mid-ocean ridge system to the climate system may provide the negative feedback that gives rise to glacial oscillations. The plausibility of this hypothesis depends on details of the response functions of the coupled systems. The proposed research group will develop a set of independent but synergistic projects that employ computational simulation to assess these responses, make testable geochemical and geophysical predictions, and validate models against observational data. This investigation has the potential to transform our understanding of mid-ocean ridge volcanism and of Quaternary ice ages.