15 • Does the budget cover just energy-related emissions, such as those used by the IEA, or are other industrial, agricultural, landuse change, etc. emissions covered as well? • Is the budget for CO2only or all greenhouse gases? Some budgets are just for carbon or carbon dioxide (check the units); others cover all 6 greenhouse gases and are expressed in CO2e (equivalent). Does a CO2 only budget assume a high or low effort to reduce other greenhouse gases? Our first analysis applied the Meinhausen et al. paper (2009) (Potsdam Institute) published in Nature which was peer reviewed research comparing a carbon budget based on a synthesis of the latest climate models available at the time. In response to feedback, our second analysis included some updated carbon budgets developed by the Grantham School of Climate Change and the Environment at LSE, led by Lord Stern. These provided carbon budgets which varied some of the factors in the bullet points above to test different levels of global warming (1.5 – 3°C). Carbon budgets continue to be a popular approach to frame the challenge of keeping global warming to ‘acceptable’ levels. The IEA regularly publishes ‘energy-sector only’ carbon budgets to deliver 2C and well below levels of warming in its World Energy Outlook. Carbon Tracker has applied these in its scenario analysis, as they provide a detailed demand picture. The IPCC AR5 (2013) is now the most cited ‘total’ carbon budgets – meaning energy sector emissions plus land use, land use change and forestry plus industrial sector emissions. Our carbon supply cost curves use the IEA 450 scenario allocation of the budget to each fuel – coal, oil and gas – to test which projects are within the budget. Signed: Mark Campanale October 28, 2018 Andrew Grant October 28, 2018