Significant Contribution of Paleogeography to Stratospheric Water Vapor Variations in the Past 250 Million Years

Abstract Stratospheric water vapor (SWV) variations play an important role in influencing the Earth's energy budget. Here, we investigate SWV past 250 million years (Myr) using a fully coupled Earth System Model. It is found that both CO 2 concentration and paleogeography have prominent influences on variations, while solar insolation plays minor role. The increases with surface warming stratospheric moistening rate accelerated during warm periods Myr except for Pangea supercontinent stage. ratio of to smaller stage compared Cretaceous Period, which due ascending consequent cooling tropical tropopause layer associated severe over supercontinent. Our results suggest factor regulating deep‐time climate.