Recognising that the rapid build up of carbon dioxide (CO2), methane (CH4) and other anthropogenic greenhouse gases (GHGs) is the primary driver of climate change, Parties to the Paris Agreement have resolved to rapidly reduce their emissions. To track progress toward this goal, Parties are compiling inventories of anthropogenic GHG emissions and removals, which are evaluated at five-year intervals in Global Stocktakes (GSTs). These GHG inventories are compiled in a bottom-up fashion, by estimating emissions from known sources and removals by known sinks in specific categories of specific sectors, and summing the results. Estimates of GHG emissions and removals can also be derived by analysing observations of their atmospheric concentrations with atmospheric inverse models to yield maps of net surface-atmosphere fluxes. In principle, these top-down GHG budgets can be used to assess the accuracy and completeness of the bottom-up methods used to compile the national inventory reports.
Rapid advances in ground-based, airborne and space-based observations of CO2 and CH4 have substantially improved the quality and utility of these top-down GHG products over the past decade. However, their adoption by national inventory compilers and the policy community has been slow, due in part by a lack of understanding of these top-down products. To mitigate this obstacle, members of the CEOS Greenhouse Gas Task Team have worked with the NASA Earth Science Applied Remote Sensing Training (ARSET) Program to develop a 3-part webinar series describing how top-down budgets of CO2 and CH4 are produced and how they might be used to support the GSTs. This webinar series will be presented on 11, 18, and 25 May 2022. By the end of this training attendees will be able to:
- Recognize the need to monitor CO2, CH4, and other greenhouse gases to support efforts to reduce net emissions and mitigate their impact on climate;
- Describe how top-down CO2 and CH4 budgets can be derived using atmospheric measurements and inverse models; and
- Relate how the products and methods described can be combined with bottom-up inventories to identify opportunities for improving GHG inventories to support future GSTs.