Designer policy for carbon and biodiversity co-benefits under global change

Transcription

1 SUPPLEMENTARY INFORMATION DOI: /NCLIMATE2874 Designer policy for carbon and biodiversity co-benefits under global change Bryan et al. Nature Climate Change Supplementary Information Supplementary Figure 1 Supply of carbon sequestration from a uniform payment scheme with land-use competition (CP and EP eligible for payments) targeting carbon sequestration (U-C-C). Includes variation across four global outlooks, three agricultural productivity rates (L low, M medium, H high) and three adoption hurdle rates (1, 2, 5 ). Circles indicate supply under the funding budget equivalent to the 2050 global outlook carbon price. NATURE CLIMATE CHANGE 1

2 Supplementary Figure 2 Supply of biodiversity co-benefits from a uniform payment scheme with land-use competition (CP and EP eligible for payments) targeting carbon sequestration (U-C-C). Includes variation across four global outlooks, three agricultural productivity rates (L low, M medium, H high) and three adoption hurdle rates (1, 2, 5 ). Circles indicate supply under the funding budget equivalent to the 2050 global outlook carbon price.

3 Supplementary Figure 3 Supply of carbon sequestration from a uniform payment scheme with land-use competition (CP and EP eligible for payments) targeting multifunctional objectives (U-C-M). Includes variation across four global outlooks, three agricultural productivity rates (L low, M medium, H high) and three adoption hurdle rates (1, 2, 5 ). Circles indicate supply under the funding budget equivalent to the 2050 global outlook carbon price.

4 Supplementary Figure 4 Supply of biodiversity co-benefits from a uniform payment scheme with land-use competition (CP and EP eligible for payments) targeting multifunctional objectives (U-C-M). Includes variation across four global outlooks, three agricultural productivity rates (L low, M medium, H high) and three adoption hurdle rates (1, 2, 5 ). Circles indicate supply under the funding budget equivalent to the 2050 global outlook carbon price.

5 Supplementary Figure 5 Supply of carbon sequestration from a uniform payment scheme targeting biodiversity co-benefits (U-CR-B).Note that the supply curves are the same for both land-use regulation (EP only eligible for payments) and land-use competition (CP and EP eligible for payments). Includes variation across four global outlooks, three agricultural productivity rates (L low, M medium, H high) and three adoption hurdle rates (1, 2, 5 ). Circles indicate supply under the funding budget equivalent to the 2050 global outlook carbon price.

6 Supplementary Figure 6 Supply of biodiversity co-benefits from a uniform payment scheme targeting biodiversity co-benefits (U-CR-B).Note that the supply curves are the same for both land-use regulation (EP only eligible for payments) and land-use competition (CP and EP eligible for payments). Includes variation across four global outlooks, three agricultural productivity rates (L low, M medium, H high) and three adoption hurdle rates (1, 2, 5 ). Circles indicate supply under the funding budget equivalent to the 2050 global outlook carbon price.

7 Supplementary Figure 7 Supply of carbon sequestration from a uniform payment scheme with land-use regulation (EP only eligible for payments) targeting carbon sequestration (U- R-C). Includes variation across four global outlooks, three agricultural productivity rates (L low, M medium, H high) and three adoption hurdle rates (1, 2, 5 ). Circles indicate supply under the funding budget equivalent to the 2050 global outlook carbon price.

8 Supplementary Figure 8 Supply of biodiversity co-benefits from a uniform payment scheme with land-use regulation (EP only eligible for payments) targeting carbon sequestration (U- R-C). Includes variation across four global outlooks, three agricultural productivity rates (L low, M medium, H high) and three adoption hurdle rates (1, 2, 5 ). Circles indicate supply under the funding budget equivalent to the 2050 global outlook carbon price.

9 Supplementary Figure 9 Supply of carbon sequestration from a uniform payment scheme with land-use regulation (EP only eligible for payments) targeting multifunctional objectives (U-R-M). Includes variation across four global outlooks, three agricultural productivity rates (L low, M medium, H high) and three adoption hurdle rates (1, 2, 5 ). Circles indicate supply under the funding budget equivalent to the 2050 global outlook carbon price.

10 Supplementary Figure 10 Supply of biodiversity co-benefits from a uniform payment scheme with land-use regulation (EP only eligible for payments) targeting multifunctional objectives (U-R-M). Includes variation across four global outlooks, three agricultural productivity rates (L low, M medium, H high) and three adoption hurdle rates (1, 2, 5 ). Circles indicate supply under the funding budget equivalent to the 2050 global outlook carbon price.

11 Supplementary Figure 11 Supply of carbon sequestration from a discriminatory payment scheme with land-use competition (CP and EP eligible for payments) targeting carbon sequestration (D-C-C). Includes variation across four global outlooks, three agricultural productivity rates (L low, M medium, H high) and three adoption hurdle rates (1, 2, 5 ). Circles indicate supply under the funding budget equivalent to the 2050 global outlook carbon price.

12 Supplementary Figure 12 Supply of biodiversity co-benefits from a discriminatory payment scheme with land-use competition (CP and EP eligible for payments) targeting carbon sequestration (D-C-C). Includes variation across four global outlooks, three agricultural productivity rates (L low, M medium, H high) and three adoption hurdle rates (1, 2, 5 ). Circles indicate supply under the funding budget equivalent to the 2050 global outlook carbon price.

13 Supplementary Figure 13 Supply of carbon sequestration from a discriminatory payment scheme with land-use competition (CP and EP eligible for payments) targeting multifunctional objectives (D-C-M). Includes variation across four global outlooks, three agricultural productivity rates (L low, M medium, H high) and three adoption hurdle rates (1, 2, 5 ). Circles indicate supply under the funding budget equivalent to the 2050 global outlook carbon price.

14 Supplementary Figure 14 Supply of biodiversity co-benefits from a discriminatory payment scheme with land-use competition (CP and EP eligible for payments) targeting multifunctional objectives (D-C-M). Includes variation across four global outlooks, three agricultural productivity rates (L low, M medium, H high) and three adoption hurdle rates (1, 2, 5 ). Circles indicate supply under the funding budget equivalent to the 2050 global outlook carbon price.

15 Supplementary Figure 15 Supply of carbon sequestration from a discriminatory payment scheme targeting biodiversity co-benefits (D-CR-B). Note that the supply curves are the same for both land-use regulation (EP only eligible for payments) and land-use competition (CP and EP eligible for payments). Includes variation across four global outlooks, three agricultural productivity rates (L low, M medium, H high) and three adoption hurdle rates (1, 2, 5 ). Circles indicate supply under the funding budget equivalent to the 2050 global outlook carbon price.

16 Supplementary Figure 16 Supply of biodiversity co-benefits from a discriminatory payment scheme targeting biodiversity (D-CR-B). Note that the supply curves are the same for both land-use regulation (EP only eligible for payments) and land-use competition (CP and EP eligible for payments). Includes variation across four global outlooks, three agricultural productivity rates (L low, M medium, H high) and three adoption hurdle rates (1, 2, 5 ). Circles indicate supply under the funding budget equivalent to the 2050 global outlook carbon price.

17 Supplementary Figure 17 Supply of carbon sequestration from a discriminatory payment scheme with land-use regulation (EP only eligible for payments) targeting carbon sequestration (D-R-C). Includes variation across four global outlooks, three agricultural productivity rates (L low, M medium, H high) and three adoption hurdle rates (1, 2, 5 ). Circles indicate supply under the funding budget equivalent to the 2050 global outlook carbon price.

18 Supplementary Figure 18 Supply of biodiversity co-benefits from a discriminatory payment scheme with land-use regulation (EP only eligible for payments) targeting carbon sequestration (D-R-C). Includes variation across four global outlooks, three agricultural productivity rates (L low, M medium, H high) and three adoption hurdle rates (1, 2, 5 ). Circles indicate supply under the funding budget equivalent to the 2050 global outlook carbon price.

19 Supplementary Figure 19 Supply of carbon sequestration from a discriminatory payment scheme with land-use regulation (EP only eligible for payments) targeting multifunctional objectives (D-R-M). Includes variation across four global outlooks, three agricultural productivity rates (L low, M medium, H high) and three adoption hurdle rates (1, 2, 5 ). Circles indicate supply under the funding budget equivalent to the 2050 global outlook carbon price.

20 Supplementary Figure 20 Supply of biodiversity co-benefits from a discriminatory payment scheme with land-use regulation (EP only eligible for payments) targeting multifunctional objectives (D-R-M). Includes variation across four global outlooks, three agricultural productivity rates (L low, M medium, H high) and three adoption hurdle rates (1, 2, 5 ). Circles indicate supply under the funding budget equivalent to the 2050 global outlook carbon price.

21 Supplementary Table 1 Total cost of payment schemes. Total cost of uniform and discriminatory carbon payment schemes ($B) in net present value terms as a once-off payment in 2050 equivalent to the 2050 global outlook carbon price under land-use competition (CP and EP eligible for payments) and land-use regulation (EP only eligible for payments) policy. Sensitivity is presented under combinations of three agricultural productivity (L low, M medium, and H high) and three adoption hurdle rate (1, 2, 5 ) assumptions. L1 M3 M2 H3 Land-use competition, targeting carbon Uniform (U-C-C) Discrim. (D-C-C) Uniform (U-C-C) Discrim. (D-C-C) Uniform (U-C-C) Discrim. (D-C-C) Uniform (U-C-C) Discrim. (D-C-C) L 1x M 1x H 1x L 2x M 2x H 2x L 5x M 5x H 5x Land-use regulation, targeting carbon Uniform (U-R-C) Discrim. (D-R-C) Uniform (U-R-C) Discrim. (D-R-C) Uniform (U-R-C) Discrim. (D-R-C) Uniform (U-R-C) Discrim. (D-R-C) L 1x M 1x H 1x L 2x M 2x H 2x L 5x M 5x H 5x

22 Supplementary Table 2 Area of potential land-use change. Area of land-use change (Mha) from agriculture to reforestation (both CP and EP) under carbon payment schemes equivalent to the 2050 global outlook carbon price given land-use competition (CP and EP eligible for payments) and land-use regulation (EP only eligible for payments). Sensitivity is presented under combinations of three agricultural productivity (L low, M medium, and H high) and three adoption hurdle rate (1, 2, 5 ) assumptions. Note that the area is the same under both the uniform and discriminatory payment schemes. L1 M3 M2 H3 CP EP Total CP EP Total CP EP Total CP EP Total Discriminatory and uniform payments, with land-use competition, targeting carbon (U-C-C and D-C-C) L 1x M 1x H 1x L 2x M 2x H 2x L 5x M 5x H 5x Discriminatory and uniform payments, with land-use regulation, targeting carbon (U-R-C and D-R-C) L 1x M 1x H 1x L 2x M 2x H 2x L 5x M 5x H 5x

23 Supplementary Table 3 Supply of carbon sequestration and biodiversity co-benefits under alternative targeting strategies with land-use competition (CP and EP eligible for payments) under payment schemes equivalent to the 2050 global outlook carbon price. Area of reforestation (both CP and EP in Mha) and the resultant carbon sequestration (MtCO2 yr -1 ) and biodiversity co-benefits (% of maximum) achieved by targeting carbon, multifunctional (both carbon and biodiversity), and biodiversity objectives. Sensitivity is presented under combinations of three agricultural productivity (L low, M medium, H high) and three adoption hurdle rate (1, 2, 5 ) assumptions. Note that the supply of carbon sequestration and biodiversity co-benefits is the same under both the uniform and discriminatory payment schemes, and that the total budget for the three targeting payment schemes is equivalent to the cost of the discriminatory carbon payment budget presented in the top half of Supplementary Table 1. L1 M3 M2 H3 Carbon Biodiv. Area Carbon Biodiv. Area Carbon Biodiv. Area Carbon Biodiv. Area Carbon targeting (U-C-C and D-C-C) L 1x M 1x H 1x L 2x M 2x H 2x L 5x M 5x H 5x Multifunctional targeting (U-C-M and D-C-M) L 1x M 1x H 1x L 2x M 2x H 2x L 5x M 5x H 5x Biodiversity targeting (U-CR-B and D-CR-B) L 1x M 1x H 1x L 2x M 2x H 2x L 5x M 5x H 5x

24 Supplementary Table 4 Supply of carbon sequestration and biodiversity co-benefits under alternative targeting strategies with land-use regulation (EP only eligible for payments) for the four global outlooks. Area of EP (Mha) and the resultant carbon sequestration (MtCO2 yr -1 ) and biodiversity co-benefits (% of maximum) achieved by targeting carbon, multifunctional (both carbon and biodiversity), and biodiversity objectives using a discriminatory payment scheme (EP only eligible for payments). Sensitivity is presented under combinations of three agricultural productivity (L low, M medium, H high) and three adoption hurdle rate (1, 2, 5 ) assumptions. Note that the supply of carbon sequestration and biodiversity co-benefits is the same under both the uniform and discriminatory payment schemes, and that the total budget for the three targeting payment schemes is equivalent to the cost of the discriminatory carbon payment budget presented in the bottom half of Supplementary Table 1. L1 M3 M2 H3 Carbon Biodiv. Area Carbon Biodiv. Area Carbon Biodiv. Area Carbon Biodiv. Area Carbon targeting (U-R-C and D-R-C) L 1x M 1x H 1x L 2x M 2x H 2x L 5x M 5x H 5x Multifunctional targeting (U-R-M and D-R-M) L 1x M 1x H 1x L 2x M 2x H 2x L 5x M 5x H 5x Biodiversity targeting (U-CR-B and D-CR-B) L 1x M 1x H 1x L 2x M 2x H 2x L 5x M 5x H 5x

25 Supplementary Figure 21 Location and extent of broad land-use within the study area.

26 Supplementary Figure 22 Prices output from GIAM modelling for the four global outlooks used as input into land-use modelling.

27 Supplementary Table 5 Description of policy mechanisms analysed in this study. Policy mechanism Payment scheme Land-use policy Targeting strategy Type Uniform Discriminatory Competition Regulation Carbon Description Reverse auction where the most cost-effective suppliers receive the same payment for carbon sequestration ($ tco 2-1 ) and biodiversity co-benefits ($ per % of maximum). Reverse auction where the most cost-effective suppliers receive a payment equivalent to their cost of supply of carbon sequestration ($ tco 2-1 ) and biodiversity co-benefits ($ per % of maximum). Both CP and EP eligible for payments. EP only eligible for payments. Payments spatially targeted by cost-effectiveness at supplying carbon sequestration (payment required per tonne of carbon sequestration). Multifunctional Payments spatially targeted by cost-effectiveness at supplying both carbon sequestration and biodiversity co-benefits weighted to achieve optimal levels (payment required per multifunctional unit). Complementary incentives Biodiversity Biodiversity premium Carbon levy Payments spatially targeted by cost-effectiveness at supplying biodiversity co-benefits (payment required per unit of biodiversity co-benefit). Additional premium payment to landholders undertaking EP in areas where CP would have otherwise been adopted. Payments equalled the difference between returns to EP and the most profitable land-use and were targeted to cost-effectively achieve biodiversity co-benefits. A levy (%) on the revenue from CP was imposed and the funds used as a biodiversity premium payment.

28 Supplementary Table 6 Properties of the global outlooks. Value Global outlook Indicator Units in 2010 L1 M3 M2 H3 Population outlook Climate change outlook - L M M H Population in 2050 World GDP per capita in 2050 World GDP in 2050 Benchmark Representative Concentration Pathway (RCP) Billion people US$ cap -1 US$ trillion Radiative forcing Wm in Atmospheric concentration in 2100 ppm CO RCP3-PD RCP4.5 RCP4.5 RCP8.5 - Peak at 3.0 then decline to (declining) (stable) 650 (stable) 1370 (rising) Greenhouse gas emissions Gt CO Emissions per capita in 2050 Coverage of greenhouse gas abatement policy Global abatement effort tco2 cap All sources All, excluding All, excluding emissions emissions from livestock from livestock No sources - Very strong Strong Modest No action Temperature change in 2050 relative to 2007 o C Rainfall change in 2050 relative to 2007 %

29 Rainfall run-off change in 2050 relative to 2007 %

30 Supplementary Table 7 Summary of mathematical notation. Variable name Symbol Units Description Scenarios, variables, sets, and indices Calendar year y Year Calendar year Model year t, T Year Each year t is a year in the rolling economic time horizon of T = 100 years. Discount rate r % pa Discount rate used to calculate net present value of future cash flow. Set at 10% pa. Global outlook o, O - Each individual scenario o is used to iterate over the full set of four scenarios O{L1, M3, M2, H3}. Adoption hurdle rates h, H Multiplier Each individual adoption hurdle rate h is used to iterate over the full set of three land-use adoption hurdle rates H{1, 2, 5 }. Indicates the number of times as profitable reforestation land-uses need to be compared to agriculture for land-use change to occur. Agricultural productivity rates u, U % pa simple increase Each individual productivity rate u is used to iterate over the full set of agricultural productivity rates U{0.0, 1.5, 3.0}. Land-uses f, F, AG, EP, CP - AG is agriculture, EP is environmental plantings, and CP is carbon plantings. F is the set of reforestation land-uses {EP, CP} and f is used to iterate over F. Multifunctionality weights, weights 0-1 Weights w in W{0.000, 0.001, 0.002,, 1.000} used to find the optimal balance between carbon sequestration and biodiversity co-benefits in calculating the index of multifunctionality. Carbon levy i, I % Carbon levy i in I{0, 1, 2,, 100%} is the levy applied to CP. Model parameters Carbon price p $ tco 2-1 Individual sale price of credits for carbon sequestration. Annual carbon sequestration ( ) tco 2 ha -1 yr -1 Annual marginal carbon sequestration adjusted for risk and climate change impacts. Average annual carbon sequestration ( ) tco 2 yr -1 Annual carbon sequestration in forest stands averaged over 100 years of growth for each grid cell adjusted for risk and climate change impacts. Discounted carbon sequestration ( ) tco 2 Annual marginal carbon sequestration of forest stands over 100 years of growth from year y for each grid cell adjusted for risk and climate change impacts, and discounted to present value terms. Total costs of reforestation ( ) $ Total cost of reforestation to the landholder including direct and opportunity costs (foregone net economic returns to agriculture) discounted to present value terms.

31 Direct costs of reforestation ( ) $ Direct costs of reforestation (superscripted f ) including establishment, annual maintenance, transaction, and water costs calculated over the 100 year horizon from year y, and discounted to present value terms. Net economic returns ( ) $ Net economic returns to agriculture (superscripted AG ) and reforestation (superscripted f ) calculated over the 100 year horizon from year, and discounted to present value terms. Breakeven price ( ) $ per unit The cost of supply of each unit of carbon sequestration and biodiversity co-benefits (targeted separately and in combination) required to change land-use. Area ha Total area of each grid cell. Biodiversity score Index Biodiversity score layer reflecting the relative value of reforestation for biodiversity. Superscripted f to indicate reforestation type, the biodiversity score for CP is 0. Biodiversity cobenefits % of max Biodiversity score multiplied by grid cell area, divided by the sum over all grid cells of the biodiversity score multiplied by grid cell area. Superscripted f to indicate reforestation type, the biodiversity co-benefits from CP is 0. Multifunctionality weight Weight 0-1 Optimal weight used to balance carbon sequestration and biodiversity co-benefits in calculating the index of multifunctionality. Multifunctionality ( ) Index Weighted index maximising carbon sequestration and biodiversity co-benefits produced by each grid cell. Model outputs Potential land-use ( ) Binary Binary variables indicating the potential for agriculture (superscripted AG ), carbon plantings (superscripted CP ), and environmental plantings (superscripted EP ). Carbon sequestration supply ( ) tco 2 Cumulative sum of average annual carbon sequestration calculated over all grid cells and sorted by breakeven price. Biodiversity cobenefits supply ( ) % Cumulative sum of biodiversity co-benefits calculated over all grid cells and sorted by breakeven price. Budget ( ) $ Cumulative payment budget in net present value terms calculated over all grid cells and sorted by breakeven price. Budget biodiversity premium ( ) $ Cumulative biodiversity premium payment budget in net present value terms calculated over grid cells where CP were the most profitable land-use, and sorted by costeffectiveness for delivering biodiversity co-benefits. Reforestation land-use ( ) Binary Identifies those grid cells where the most profitable reforestation land-use (i.e. CP or EP) was more profitable than agriculture. Total budget ( ) $ The total payment budget summed over grid cells whose breakeven price was less than or equal to the global outlook

32 carbon price. Carbon sequestration supply ( ) tco 2 Total supply of carbon sequestration. Biodiversity cobenefits supply Biodiversity premium payment ( ) % ( ) $ Total supply of biodiversity co-benefits. Biodiversity premium payment (opportunity cost) of adopting EP rather than CP, in present value terms. Differential carbon sequestration Costeffectiveness ( ) tco 2 The difference in average annual carbon sequestration between CP and EP. ( ) Index Index of cost-effectiveness for prioritising grid cells for biodiversity premium payments. Carbon levy ( ) $ Carbon levy payable for CP.