Large changes in the Earth's hydrological cycle have been observed in the paleoclimate record and are projected to emerge as the climate warms. Expected responses to global warming include an enhancement of the climatological water cycle, the so-called "rich-get-richer" effect, and increases in global-mean precipitation and evaporation of approximately 2% per degree of surface warming. However, these processes are insufficient to explain the hydrological cycle changes at the regional scale and future model projections remain highly uncertain, particularly over land. Challenges also remain in reconciling paleoclimate records of the hydrological cycle with theory and simulations. This points to a lack of understanding of the physical mechanisms controlling the hydrological cycle, particularly the roles of changes in atmospheric circulation, clouds, and soil moisture. The objective of this session is to advance our understanding of the large-scale hydrological cycle under past and future climate change and we encourage theoretical, observational, and modeling contributions on this topic.