A WMO-coordinated Global Greenhouse Gas Monitoring Infrastructure

Beyond water vapor, the three most important greenhouse gases (GHGs) in terms of their radiative forcing are carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Increasing concentrations of these gases driven by human activities are the primary cause of the observed climate change according to the Intergovernmental Panel on Climate Change (ref AR6 WG1). The Paris Agreement, adopted by 196 countries at the UNFCCC Conference of the Parties in 2015, sets specific targets for maximum rise in global mean temperature and identifies reduction in net greenhouse emissions as the primary means to achieve this target.
However, even very accurate estimates of anthropogenic emissions alone will not be enough to design meaningful mitigation efforts or to monitor their effectiveness. Greenhouse gas concentrations are influenced by both natural and anthropogenic processes, and some of the natural carbon sources and sinks in particular are associated with very large uncertainties, both as they currently operate and as they may change in the future in response to climate change. 
Sustained, routine monitoring of greenhouse gas concentrations, using monitoring of weather and climate as a paradigm and role model, will provide a wealth of quantitative data to help constrain the modelling of all parts of the carbon cycle. This will be extremely valuable for the work of the World Climate Research Programme (WCRP) and IPCC, it will complement and supplement existing methodologies used to estimate anthropogenic emissions, and it will help put mitigation steps taken by Parties to the Paris Agreement on a solid scientific footing. 
This presentation introduces a WMO-coordinated effort to establish an operational Global Greenhouse Monitoring Infrastructure to directly observe and model greenhouse gas concentrations in the atmosphere, and thereby support/enable estimates of net greenhouse gas fluxes between atmosphere, land, and oceans. The atmospheric component of this infrastructure builds on the research infrastructure for greenhouse gas observations and modelling supported by WMO since 1975, and promotes its operationalization and further advancement by utilizing the existing infrastructure and methodologies employed for more than 50 years for operational weather forecasting.