The EU's commitment to reducing GHG emissions demonstrates its determination to combat climate change. This is reflected in the EU-funded 'Integrated carbon observation system' (ICOS) project, which aims to build an infrastructure for coordinating GHG data for Africa, Europe and Siberia. A central facility, known as ICOS-centre, was established and is responsible for the coordination, calibration and handling of data. In addition, networks were set up for conducting atmospheric and ecosystem observations. The consortium also founded a Central Analytical Laboratory that provides calibration, quality control and atmospheric analysis services for the whole network. In addition, an Atmospheric Thematic Centre will be created for air sampling, data processing, and instrument development and servicing. Long-term observations were conducted to gain a clearer picture of the global carbon cycle as well as GHG emissions and the factors that influence their composition in the atmosphere. Project partners monitored carbon dioxide, methane, carbon monoxide and carbon-14 in order to determine fossil fuel components. Researchers determined the effectiveness of carbon sequestration and GHG reduction on the composition of the global atmosphere. This included attributing sources and sinks according to region, industrial sector and type of ecosystem. By establishing an Ecosystem Thematic Centre, the project evaluated slow-changing quantities like biomass and soil carbon content. A common data centre, the Carbon Portal, will provide free access to ICOS measurements and other relevant carbon cycle data, in particular fossil fuel emissions. ICOS will improve the information on regional carbon fluxes available to the general public and decision makers, lead to more effective investment in infrastructure projects and help improve climate change models. The project will therefore help to mitigate the effects of climate change and enhance the lives of EU citizens.