The Copernicus Climate Change Service (C3S) is an institution, specifically one of the six thematic information services provided by the European Union's Copernicus Programme, which is the EU's flagship Earth observation initiative. The service was entrusted to the European Centre for Medium-Range Weather Forecasts (ECMWF) by the European Commission in November 2014 and became fully operational in 2018. Its creation was driven by the need to provide reliable, authoritative information for a better understanding of climate change and its impacts, supporting mitigation and adaptation policies.
The core mechanism of C3S involves combining observations of the climate system with the latest science to develop quality-assured data about the past, current, and future states of the climate globally. It provides free and open access to this information through its Climate Data Store (CDS), a cloud-based infrastructure that offers climate data records, reanalyses like ERA5, seasonal forecasts, and climate projections. The service's portfolio includes consistent estimates of multiple Essential Climate Variables and global/regional reanalyses covering the atmosphere, ocean, land, and carbon.
C3S is intrinsically connected to the broader Copernicus Programme, which is implemented in partnership with institutions like the European Space Agency (ESA) and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). The data it uses is sourced from the Copernicus Space Component, which includes the dedicated Sentinel satellites, and ground-based ("in-situ") measurement systems. The service also relies on climate research from the World Climate Research Programme (WCRP) and contributes to the Global Framework for Climate Services (GFCS). Since its full operational launch, the service has not been replaced, but its data and reports, such as the annual European State of the Climate and monthly climate bulletins, continue to be updated and widely disseminated.