Environment and Climate Change Canada has a multi-scale approach to the development of comprehensive carbon data assimilation systems. The desire is to obtain flux estimates of CO2 and CH4 over Canada from national to provincial to urban scales using atmospheric and geophysical observations from a variety of platforms (in situ and remote sensors). These systems are needed for addressing carbon science questions from the Canadian perspective such as: the quantification of natural sources and sinks of CO2 in boreal regions and the monitoring of GHG emissions over a potentially thawing permafrost. They should also provide the capability to detect the impact of potential mitigation efforts on CO2 and CH4 emissions with the aim to provide timely information to stakeholders. The global scale system is called EC-CAS (ECCC Carbon Assimilation System) and the atmospheric transport and assimilation schemes are based on operational codes (the operational environmental forecast model and ensemble Kalman filter) from the Canadian Meteorological Centre. EC-CAS global GHG distributions (on a 90 km grid) are then used to constrain the regional (10 km grid size) model on the North American domain. The regional model concentrations can then provide background concentrations to the urban scale inversions. The urban scale project over the Greater Toronto and Hamilton area (led by F. Vogel) is part of the IG3IS test bed, which aims to provide actionable information on GHG emission (trends) to stakeholders at different governmental levels. This poster will present an overview and status report of the various ECCC flux estimation efforts.