IPSL research themes point to many burning research questions where progress is urgently needed in view of current societal questions on climate evolution and environmental transition. Among the many questions, one can list climate tipping points, extreme events and their impacts, climate variability driven by volcanic eruptions and megafires (paleoclimate and climate variability themes); the study of critical hotspots such as urban environments, coastal regions, polar regions; climate mitigation through changes in practice such as land use, irrigation methods, surface and groundwater use (water cycle theme); threats to the ocean associated with climate change, extreme events, ocean circulation tipping points, as well as with human activities (marine biogeochemistry theme); observation and modelling of emerging pollutants such as ammonia and ultrafine particles and of health effects through oxidative potential, with a better characterization of individual exposure (Compos’Air theme).