The United Nations Framework Convention on Climate Change (UNFCCC) is the leading international treaty for action on climate change. Parties to the Convention, including the US & Australia, must submit annually a national greenhouse gas inventory, which tracks emissions and their various sources over time. The Kyoto Protocol to the Convention also requires parties to commit to binding emission reduction targets: the inventories are central to tracking progress towards these targets. This seminar explains the UN carbon accounting principles and how national greenhouse gas inventories are constructed for reporting under these international instruments. The Australian Inventory is presented as a focal case study: the data sources and estimation methods are detailed, and trends are discussed across the Energy, Industrial Processes, Agriculture, Waste and Land Sectors. The many parallels with the US Inventory experience are explored, and the UN’s expert peer review process, a critical Quality Assurance measure, is described.