To support the Commission and the CO2 Task Force with designing and ultimately building the CO2MVS, the CO2 Human Emissions (CHE) project was funded through the H2020 programme. The project started in October 2017, bringing together a consortium of 22 European partners and lasting for over three years. The project, coordinated by ECMWF, has carried out various scientific studies supporting the design of the CO2MVS, resulting in clear recommendations described in a set of reports. In parallel, the Commission has been funding through H2020 the VERIFY project, which runs from February 2018 until January 2022. VERIFY, coordinated by the Laboratoire des Sciences du Climat et de l'Environnement (LSCE), is developing a system to estimate greenhouse gas emissions in European countries to support countries' emission reporting to the UN Climate Change Convention Secretariat. The emissions are estimated based on existing land, ocean and atmospheric observations. VERIFY focuses on the three major greenhouse gases responsible for global warming: carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). The H2020 CoCO2 (2021-2023) project, coordinated by ECMWF, will transfer the results from these projects into a preoperational framework that can then be further developed into a fit-for-purpose operational system.