We cannot predict the exact technological changes that will help us deliver on the fourth and fifth carbon budgets (and beyond). Some technologies will develop faster than expected, making it easier to reduce emissions in particular sectors. Some technologies may develop less quickly than we hope. Total sector emissions reductions are compared against estimated 2017 levels. Supplementary metrics, where relevant, compared the 2032 pathway with 2015 official statistics. See Table 4 in Annex D, and Table 6 in the Technical Annex for details. The approach could involve¹50,