The lack of international cooperation and agreement surrounding GHG emissions impedes energy transition pathways, including the Circular Carbon Economy (CCE) approach endorsed by the 2020 G20 Summit to advance hard-to-abate sectors towards carbon neutrality. This Policy Brief recommends that the G20 support the development of and adherence to consistent measuring, reporting, and certifying of emissions by industries, along with energy usage. It proposes the G20 adopt a three-point action plan and create a body to implement it: (a) measuring emissions over products’ lifecycles; (b) reporting emissions according to standardised and transparent Generally Accepted Emissions Accounting Principles; and (c) certifying GHG-content following internationally recognised methodologies. This plan is indispensable for successfully implementing the CCE and climate change response measures.