a, Projected global average annual growth rates under SSP1 with and without climate change; estimates are averaged across bootstraps and climate models. Projected growth rates with climate change are used to define future consumption growth in Ramsey-based discount rates. b, Evolution of discount rates under different schemes through 2099. Ramsey-based schemes are Stern30, Weitzman31 and Nordhaus32, with corresponding assumptions about the pure rate of time discount ρ and the elasticity of marginal utility of consumption η shown in parentheses. Dashed lines are versions of these Ramsey-based discounting schemes that account for growth-rate uncertainty. Non-Ramsey schemes are Newell and Pizer35 and Groom36. c, Projected average annual growth rates separately for rich and poor countries under SSP1, with and without climate change. d, Corresponding Ramsey-based discount rates calculated separately for rich and poor countries, using income-specific growth rates from c.