The ICOS infrastructure provides Europe-wide, continuous long-term measurements of CO₂, CH₄ and N₂O concentrations in the atmosphere based on a network of tall towers. Near-surface observation stations measure simultaneously the turbulent exchange of these trace gases between the most representative managed and natural ecosystems. The greenhouse gas budgets of the European seas and the North Atlantic are continuously monitored by automated measurements from voluntary observing ships and at time series observatories.

Very small concentration differences between different atmospheric measurement stations can provide important information on the spatial distribution of greenhouse gas emissions. Therefore highest precision of the data is an essential requirement for the ICOS measurements. To achieve highest quality and long-term consistency of the data, the ICOS concept is built on the development of two central laboratories for trace gas and 14C measurements, respectively. These laboratories will provide calibration gases for all European ICOS stations and will measure additional parameters in gas samples which cannot be measured continuously at the atmospheric observation stations.

In the past, only few laboratories were able to deliver highest precision and best possible standardization of trace gas measurements. One of them is the Max-Planck Institute of Biogeochemistry in Jena which has now built up the Flask and Calibration Laboratory (FCL) for ICOS. Another Central Laboratory has been developed at the Institute of Environmental Physics at Heidelberg University. The Central Radiocarbon Laboratory (CRL) conducts measurements of the ¹⁴C isotope content in gas samples which serves to distinguish between natural and anthropogenic sources of atmospheric carbon dioxide. With these two laboratories Germany provides a core part of the ICOS research infrastructure.