Recommendation 27

In its 2020 report Achieving net zero, the NAO stated that neither the Department nor HM Treasury collated information on the total costs and benefits of government policies that contribute to achieving net zero.96 HM Treasury told us that costs associated with achieving the Nationally Determined Contribution (which commits the UK to reducing economy-wide greenhouse gas emissions by at least 68% by 2030 compared to 1990 levels), achieving the Sixth Carbon Budget, contributing to international climate finance, and any UK commitments made at COP26 are already covered either in the current Spending Review settlement, or will be covered by future spending reviews.97 HM Treasury also told us that the Climate Change Committee produces cost estimates over much longer periods, for example 30 years, and the Office for Budgetary Responsibility produces an official estimate of the future costs of climate adaptation and mitigation in its fiscal risks report over an even longer time horizon of 50 years.98 However, HM Treasury cautioned that such estimates contain ‘heroic assumptions’ with errors compounding over potentially very long periods.99 It concluded in its Net Zero Review that costs and benefits will not fall 88 HM Treasury, Net Zero Review Final Report, October 2021, para 2.33 89 IFRS, IFRS Foundation announces International Sustainability Standards Board, consolidation with CDSB and VRF, and publication of prototype disclosure requirements 90 Qq 109–110 91 Net Zero Strategy, page 254, para 30 92 Q 62 93 Q 63 94 Q 64–65 95 Net Zero Strategy, page 254, para 30 96 Q 70; C&AG’s Report, para 17 97 Qq 87–92; UK Government, United Kingdom of Great Britain and Northern Ireland’s Nationally Determined Contribution, 2020 98 Qq 95–96, 105–107 99 Q 95, 97 18 Achieving Net Zero: Follow up evenly, but that it was impossible to forecast how individual households would be affected over the thirty-year transition given consumer costs would be driven by factors including incomes, prefer