If I use your SCC function, or if I take the marginal damages from the “marignal model” used for that SCC estimate and discount them, I get results that differ by ~ $2. In this case I’m just using what I think is the equation you use to calculate discount factors. Perhaps I’m missing something basic here, but shouldn’t these give the same results?
Here’s some replication code:
using MimiDICE2013 # DICE model years. model_years = 2010:5:2305 # Emission pulse year and index. year = 2020 year_index = findfirst(isequal(year), model_years) # Last model year. last_year = 2305 # Discounting stuff using Mimi discounting code. eta = 0.0 prtp = 0.03 cpc = ones(60) df = [zeros(year_index-1)..., ((cpc[year_index]/cpc[i])^eta * 1/(1+prtp)^(t-year) for (i,t) in enumerate(model_years) if year<=t<=last_year)...] # SCC from function. scc, marginal_model = MimiDICE2013.compute_scc_mm(year=pulse_year, last_year=2305, prtp=0.03, eta=0.0) # Calculated marginal damages. marginal_damages = marginal_model[:damages, :DAMAGES] # SCC from these marginal damages. other_scc = sum(marginal_damages .* df) * 5 * 1e12