14 the budget now being forced out by competitive supply having experienced greater reductions in costs. Accordingly, as would be expected, there have been some material moves in relative positioning since the previous 2 Degrees of Separation report (see report for full table). Reasons for these movements for a given company vary, but generally fall into one or more of several broad themes: Appendix 3 Carbon Budgets At the 2015 UNFCCC Paris COP, world governments confirmed their intention to limit global warming “well below 2°C” and pursue efforts to “limit the temperature increase to 1.5°C”. The upper limit of 2°C is a frequently used reference point for delineating a carbon budget. The nature of climate science means that the probabilistic scenarios used produce a range of budgets depending on the parameters applied to the models. In selecting / using a budget, people should be aware of: • What the probability of the delivering the desired global warming outcome is: 50%, 66%, 80%? The more likely the scenario is to achieve the outcome, the smaller the carbon budget will be. • What time period is covered: The IPCC AR5 budgets start in 2011, meaning some of those budgets have already been used up. • What assumptions are made for certain climate variables: Climate sensitivity is one variable that can significantly impact the size of the carbon budget. As is the degree to which net-negative emissions are deployed.