The Integrated Carbon Observation System, ICOS, provides standardised and open data from more than 140 measurement stations across 13 European countries. The stations observe greenhouse gas concentrations in the atmosphere as well as carbon fluxes between the atmosphere, the land surface and the oceans. The ICOS community consists of more than 500 scientists in both its current Member and Observer countries and beyond. More than 80 renowned universities or institutes are a part of the ICOS community. The ICOS community has strong connections to colleagues and operators outside ICOS. ICOS-based knowledge supports policy- and decision-making to combat climate change and its impacts.