It is imperative to place the global warming of the last century in a broader temporal context in order to determine its singularity and distinguish the underlying causes, both natural and anthropogenic. Paleoclimatic variations can be used to test multiple hypotheses, with records that are generally sufficiently reliable. The lectures cover climate forcings, the respective roles of the ocean and the carbon cycle, and climate history from the earliest ages of the Earth to the modern period, including extreme climates and present-day analogues.

Edouard Bard conducts research at the interface of climatology, oceanography and geology. The main objective is to understand the natural functioning of the ocean-atmosphere-cryosphere-biosphere system on timescales ranging from a few decades to several million years. Variations in the climate system involve mechanisms with very different time constants, so a long-term perspective is crucial to distinguish the effects of climate forcings according to their geological, astronomical and anthropogenic origins. Another feature of this research is the back-and-forth flow of information between recent and older periods, including modern environments.

Edouard Bard and his team use geochemistry to determine the magnitude and chronology of climatic variations. New quantitative methods have enabled them to reconstruct past environments from varied archives such as ocean sediments, corals, stalagmites, lake sediments and polar ice. The common thread is the desire to study the same climatic phenomena, such as glaciations, using complementary and innovative techniques of organic, inorganic and isotopic geochemistry, as well as isotopic geochronology. To study the past, they use " time machines " - i.e. complex mass spectrometers to measure radioactive isotopes and thus precisely date the climatic variations recorded in the various archives.