The Climate Observation and Modelling Expertise Team (COMET) aims to enhance the use of satellite-derived climate data in ocean and sea ice modelling by integrating high-quality long-term Earth Observation records from ESA’s Climate Change Initiative (CCI) for key Essential Climate Variables (ECVs) such as sea surface temperature and salinity, sea ice, and sea. By applying advanced data assimilation, model calibration, and machine learning techniques, COMET addresses key scientific challenges in climate modelling, particularly in polar regions, and contributes to more accurate and reliable representations of present and future climate conditions. The project strengthens links between the Earth Observation and modelling communities under ESA’s Climate-Space initiative and responds to scientific priorities set by the IPCC, WCRP, and GCOS, focusing on better representation of ocean–ice–atmosphere interactions in climate models. It addresses scientific priorities set by the IPCC, WCRP and GCOS, focusing on better representation of ocean–ice–atmosphere interactions in climate models. By improving the physical consistency, usability, and assimilation of satellite ECVs, COMET helps deliver more reliable climate predictions, particularly for vulnerable regions such as the Arctic.