At the CHE-VERIFY Joint General Assembly, Glen Peter (CICERO), Roxana Petrescu (VU) and Philippe Ciais (CEA-LSCE) introduce the progress and plans for the VERIFY WP5 and WP6. The overall objective of WP5 is to provide the process through which different scientific data-streams on GHG budgets from WP2, WP3, and WP4 will be synthesized for comparison with official inventories in WP6. WP6 will provide a prototype of an observation-based system to monitor GHG sources & sinks and to verify emission trends. This prototype will integrate scientific results from the approaches used in WP2-5 to quantify GHG budgets and their uncertainties and will translate them into actionable, policy-relevant information. ‘Actionable’ refers to best practices anchored to data standards, transfer of information and tools to improve national and EU emissions and assess their trends. These tools will be designed to be applicable to other countries outside Europe.