With the construction of the stations and laboratories almost completed and the station labelling well under way there was plenty of time for scientific discussions about new data from the stations and laboratories and about the role of the ICOS infrastructure in a European and global context. The presentations can be found here on the ICOS-D homepage. A particular focus was on the cooperation of ICOS ERIC with other international research infrastructures on environmental observations. Remote sensing observations and in situ ground based data as collected by ICOS were identified as complementary parts of a comprehensive strategy to verify GHG emission inventories, which will also need a strong atmospheric inversion modelling and data assimilation component. The stakeholders encouraged the participating scientists to visualise in an easily understandable way what kind of novel information for science and policy ICOS is able to provide as soon as the infrastructure is completed and in operational mode later this year.