1. Calculate the benefits for each year of each scenario and discount them in columns C and D.
2. Sum up these benefits to calculate the present value for each scenario.
3. Calculate the costs for each year of each scenario and discount them in columns F and G.
4. In row 25, calculate the net present value for each scenario by subtracted the appropriate discounted costs from each of the discounted benefits.

Social Cost of Carbon = Benefits of Avoided Pollution 40.0 40.8 41.6 42.4 43.2 44.0 44.8 45.6 46.4 47.2 48.0 49.0 50.0 51.0 52.0 53.0 54.0 55.0 56.0 57.0 58.0 Abatement of CO2 (millions of tons) Total PV NPV 81.0 117.8 154.6 191.4 228.2 265.0 294.6 324.2 353.8 383.4 413.0 413.0 413.0 413.0 413.0 413.0 413.0 413.0 413.0 413.0 413.0 Scenario 2: PV at variable Scenario 1: PV discounting: 3.5% year 0 to at 5% 10; 1.5% years 11-20 3240.0 4577.4 3240.00 4643.71 variable discounting: 3.5% Abatement costs ($ PV costs at year 0 to 10; 1.5% millions) 5% years 11-20. 1400.00 1720.00 2040.00 2360.00 2680.00 3000.00 3420.00 3840.00 4260.00 4680.00 5100.00 5100.00 5100.00 5100.00 5100.00 5100.00 5100.00 5100.00 5100.00 5100.00 5100.00 1400.00 1638.10 1400.00 1661.84 Time 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 1890 20 year 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040