Global Climate Observing System

Global Climate Observing System is an international climate-observation coordination programme hosted by WMO in Geneva and launched in 1992 after the 1990 Second World Climate Conference.^[1][2] It does not operate satellites or instruments; it defines requirements, coordinates observing systems, and works through member agencies and expert panels to improve observations for monitoring, understanding, and predicting climate.^[2][3]

GCOS maintains the Essential Climate Variables framework, covering 50 physical, chemical, and biological variables used to observe Earth's changing climate.^[2] Its governance includes a Steering Committee and atmospheric, ocean, and terrestrial observation panels, with national focal points and coordinators connecting global requirements to national observing systems.^[2] The co-sponsor record includes one science-council sponsor whose current and former names refer to the same body after a 2018 rename.^[2][4] For buyers and data providers, GCOS is a requirements and coordination authority rather than a data-product operator or satellite mission owner.^[2]