(001) Capital = INTEG(Investment - Depreciation, Reference_Capital)
Units: $
Capital ($) Capital stock in 1989 dollars. [Managing Global Commons, pg. 21]
Causes:
Uses:
(002) Capital_Energy_Coeff = (Capital_Energy_Elast-1)/Capital_Energy_Elast
Units: dmnl
Coefficient of capital-energy substitution.
Causes:
Uses:
(003) Capital_Energy_Elast = 0.7
Units: dmnl
Elasticity of subsitution between capital and effective energy inputs.
Uses:
(004) Capital_Labor_Ratio = Capital/Population
Units: $/person
Ratio of Capital Inputs to Labor Inputs ($/person)
Causes:
(005) Capital_Output_Ratio = Capital/Gross_Output
Units: $/($/year)
Capital per Unit Output ($ per $/year)
Causes:
(006) Capital_Share = 1-Energy_Share
Units: dmnl
Share of capital in producing effective capital.
Causes:
Uses:
(007) Depreciation = Capital*Depreciation_Rate
Units: $/year
Depreciation
Causes:
Uses:
(008) Depreciation_Rate = 0.065
Units: 1/year
Depreciation Rate [delta-k] (1/year) Nordhaus uses exp(-.1*10)=.65 to convert the assumed capital life of 10 years to a decadal depreciation rate of .65. This is generally a poor way to correct for integration error due to insufficient compounding, and is wrong as applied because the net rate (investment-depreciation) must be compounded; depreciation cannot be treated in isolation. Using the annual rate of .1 causes insufficient capital growth, so I have converted the decadal rate of .65 to an annual rate of .065. [Managing Global Commons, pg. 21]
Uses:
(009) Effective_Capital = Reference_Eff_Capital*(Capital_Share*(Capital/Reference_Capital )^Capital_Energy_Coeff +(1-Capital_Share)*(Energy_Serv_Demand/Ref_Energy_Serv_Demand)^Capital_Energy_Coeff )^(1/Capital_Energy_Coeff )
Units: $
Effective capital inputs to production, obtained by CES aggregation of capital and effective energy inputs.
Causes:
Uses:
(010) Energy_Int_Adj_Time = 10
Units: year
Energy intensity adjustment time; set shorter than capital life and decoupled from investment for simplicity; assumes costless retrofit potential.
Uses:
(011) Energy_Intens_Chg_Rt = (Ind_Energy_Cap_Ratio-Energy_Intens_of_Capital )/Energy_Int_Adj_Time
Units: GJ/year/$/year
Rate of change of energy intensity.
Causes:
Uses:
(012) Energy_Intens_Dec_Rt_Decline_Rt = Energy_Intens_Decline_Rt*Fact_Prod_Gr_Rt_Dec_Rt
Units: 1/year/year
Rate of decline of Rate of Decline of CO2 intensity (i.e. a second derivative or CO2 intensity).
Causes:
Uses:
(013) Energy_Intens_Decline_Rt = INTEG(- Energy_Intens_Dec_Rt_Decline_Rt, Init_Energy_Intens_Dec_Rt )
Units: 1/year
Rate of Decline of Greenhouse Gas Intensity of Output [g-sigma] (1/year) Note that Nordhaus decompounds the decadal rate of .1168 to yield an annual rate of .0125; I have simply divided by 10 to convert the decadal rate to an annual rate. [Managing Global Commons, pg. 21]
Causes:
Uses:
(014) Energy_Intens_of_Capital = INTEG(Energy_Intens_Chg_Rt,Ref_Energy_Serv_Demand /Capital)
Units: GJ/year/$
Energy intensity of capital stock.
Causes:
Uses:
(015) Energy_Serv_Demand = Energy_Intens_of_Capital*Capital
Units: GJ/year
Energy requirements of capital
Causes:
Uses:
(016) Energy_Share = INTEG(-Energy_Share*Energy_Intens_Decline_Rt,Initial_Energy_Share )
Units: dmnl
Share of energy in the capital-energy composite good. Declines at an exogenous rate.
Causes:
Uses:
(017) Ind_Energy_Cap_Ratio = Ref_Energy_Serv_Demand/Reference_Capital *(Energy_Price/Marg_Prod_Capital*Capital_Share/(1-Capital_Share) *Ref_Energy_Serv_Demand/Reference_Capital)^(1/(Capital_Energy_Coeff-1))
Units: GJ/year/$
Indicated energy-capital ratio. Equal to the CES optimal factor ratio at current prices. Terms can be rearranged to eliminate units error.
Causes:
Uses:
(018) Init_Energy_Intens_Dec_Rt = 0.015
Units: 1/year
Initial rate of decline of energy intensity (i.e. energy share of capital/energy composite good).
Uses:
(019) Initial_Energy_Share = 0.08
Units: dmnl
Initial share of energy in the composite capital-energy good.
Uses:
(020) Investment = Output*Investment_Frac
Units: $/year
Gross Investment ($/year)
Causes:
Uses:
(021) Marg_Prod_Capital = Marg_Prod_Eff_Capital*(Reference_Eff_Capital/Reference_Capital ) *(Capital_Share*(Capital/Reference_Capital)^Capital_Energy_Coeff +(1-Capital_Share)*(Energy_Serv_Demand/Ref_Energy_Serv_Demand)^Capital_Energy_Coeff ) ^(1/Capital_Energy_Coeff-1) *Capital_Share*(Capital/Reference_Capital)^(Capital_Energy_Coeff-1)
Units: 1/year
Marginal Productivity of Capital (gross, not including depreciation).
Causes:
Uses:
(022) Marg_Prod_Eff_Capital = Capital_Elast_Output*Gross_Output/Effective_Capital
Units: 1/year
Marginal Productivity of Capital
Causes:
Uses:
(023) Marg_Prod_Energy = Marg_Prod_Eff_Capital*(Reference_Eff_Capital/Ref_Energy_Serv_Demand ) *(Capital_Share*(Capital/Reference_Capital)^Capital_Energy_Coeff +(1-Capital_Share)*(Energy_Serv_Demand/Ref_Energy_Serv_Demand) ^Capital_Energy_Coeff)^(1/Capital_Energy_Coeff-1) *(1-Capital_Share)*(Energy_Serv_Demand/Ref_Energy_Serv_Demand)^(Capital_Energy_Coeff -1)
Units: $/GJ
Marginal Productivity of Energy
Causes:
(024) Marg_Return_Capital = Marg_Prod_Eff_Capital-Depreciation_Rate
Units: 1/year
Marginal Return to Capital Equals the marginal product of capital less depreciation.
Causes:
Uses:
(025) Ref_Energy_Serv_Demand = INIT(Energy_Share*Capital_Elast_Output*Output_in_1965 /Energy_Price)
Units: GJ/year
Reference demand for energy services.
Causes:
Uses:
(026) Reference_Capital = 1.6e+013
Units: $
Reference capital input in composite capital/energy good.
Uses:
(027) Reference_Eff_Capital = 1.6e+013
Units: $
Reference value (output) of composite capital/energy good. Selected to have same value as initial capital in Nordhaus for comparability.
Uses:
(028) Atmos_Retention = (CO2_Net_Emiss-CO2_Storage)/CO2_Net_Emiss
Units: dmnl
Total (average) atmospheric retention in Nordhaus carbon cycle.
Causes:
Units: dmnl
0 = Nordhaus, 1 = modified
Uses:
(030) CO2_Content[carbon] = 0.01773 CO2_Content[non_carbon] = 0 CO2_Content[alt_carbon] = 0.01773
Units: TonC/GJ
CO2 content of energy sources. Corresponds to .065 TonCO2/GJ.
Uses:
(031) CO2_Emissions = SUM(Energy_CO2_Emiss[source!])+Nonenergy_CO2_Emiss
Units: TonC/year
Total CO2 emissions.
Causes:
Uses:
(032) CO2_in_Atmos = INTEG(CO2_Net_Emiss - CO2_Storage, Init_CO2_in_Atm)
Units: TonC
Greenhouse Gases in Atmosphere [M(t)] (tons carbon equivalent) [Cowles, pg. 21]
Causes:
Uses:
(033) CO2_Int_of_Output = CO2_Emissions/Gross_Output
Units: TonC/$
Carbon Intensity of Output
Causes:
(034) CO2_Net_Emiss = Marginal_Atmos_Retention*CO2_Emissions
Units: TonC/year
Net Greenhouse Gas Emissions (tons carbon equivalent/year) Greenhouse gas emissions less short-run uptake from the atmosphere. Where does the portion not retained go in the long run? [Cowles, pg. 21]
Causes:
Uses:
(035) CO2_Rad_Force_Coeff = 4.1
Units: watt/meter/meter
Coefficient of Radiative Forcing from CO2 (W/m^2) Coeff. of additional surface warming from accumulation of CO2. [Cowles, pg. 22]
Uses:
(036) CO2_Rad_Forcing = CO2_Rad_Force_Coeff*LOG(IF_THEN_ELSE(Carbon_Cycle_Switch =0, CO2_in_Atmos,CO2_in_Atmosphere)/Preindustrial_CO2,2)
Units: watt/meter/meter
Radiative Forcing from CO2 [F(t)] (W/m^2) Additional surface warming from accumulation of CO2. [Cowles, pg. 22]
Causes:
Uses:
(037) CO2_Storage = (CO2_in_Atmos-Preindustrial_CO2)*Rate_of_CO2_Transfer
Units: TonC/year
Greenhouse Gas removal from the atmosphere and storage by long-term processes. (tons carbon equivalent/year) [Cowles, pg. 21]
Causes:
Uses:
(038) Emiss_Stabilization = Emiss_Stabilization_LOOKUP(Time)
Units: dmnl
Fraction of CO2 and CFC Emissions Controlled (dimensionless) Stabilization of Emissions. Estimated from graph in [Science, Fig. 1]. (000)Time - Internally defined simulation time.
Causes:
Uses:
(039) Emiss_Stabilization_LOOKUP( (1965, 0), (1975, 0), (1985, 0), (1995, 0.13 ), (2005, 0.27), (2015, 0.36 ), (2025, 0.45), (2035, 0.51), (2045, 0.55), (2055, 0.59), (2065, 0.62), (2075 , 0.64), (2085, 0.66), (2095, 0.68), (2105, 0.7) )
Units: dmnl
Fraction of CO2 and CFC Emissions Controlled (dimensionless) Stabilization of Emissions. Estimated from graph in [Science, Fig. 1].
Uses:
Units: dmnl
1 = no control; 2 = optimal control; 3 = emissions stabilization; 4 = temperature stabilization
Uses:
(041) Energy_CO2_Emiss[source] = Production[source]*CO2_Content[source]
Units: TonC/year
Causes:
Uses:
(042) IPCC_CO2_CFC_Rad_Force = IPCC_CO2_CFC_Rad_Force_LOOKUP(Time)
Units: watt/meter/meter
IPCC Scenario for Radiative Forcing from CO2 and CFCs (W/m^2) As interpolated by Nordhaus. [Cowles, Table III.E-5] (000)Time - Internally defined simulation time.
Causes:
(043) IPCC_CO2_CFC_Rad_Force_LOOKUP( (1965, 0.92), (1975, 1.19), (1985, 1.57 ), (1995, 2), (2005, 2.46), (2015 , 2.93), (2025, 3.4), (2035, 3.97), (2045, 4.54), (2055, 5.11), (2065, 5.68 ), (2075, 6.25), (2085, 6.79 ), (2095, 7.33), (2105, 7.87) )
Units: watt/meter/meter
IPCC Scenario for Radiative Forcing from CO2 and CFCs (W/m^2) As interpolated by Nordhaus. [Cowles, Table III.E-5]
Uses:
(044) Marginal_Atmos_Retention = 0.64
Units: dmnl
Atmospheric Retention Fraction [beta] (dimensionless) Fraction of Greenhouse Gas Emissions which accumulate in the atmosphere. [Cowles, pg. 21]
Uses:
Units: dmnl
Fraction of CO2 and CFC Emissions Controlled (dimensionless) Uncontrolled scenario.
Uses:
(046) Nord_CO2_in_Atm = Nord_CO2_in_Atm_LOOKUP(Time)
Units: GTonC
Nordhaus' CO2 & CFC Concentrations (Gt Carbon Equivalent) Uncontrolled scenario [Cowles, Table IV-4]. (000)Time - Internally defined simulation time.
Causes:
(047) Nord_CO2_in_Atm_LOOKUP( (1965, 677), (1975, 698), (1985, 727), (1995, 764), (2005, 809), (2015, 0), (2025, 921), (2035, 0), (2045, 0), (2055, 0), (2065, 0), (2075, 1293), (2085 , 0), (2095, 0), (2105, 0) )
Units: GTonC
Nordhaus' CO2 & CFC Concentrations (Gt Carbon Equivalent) Uncontrolled scenario [Cowles, Table IV-4].
Uses:
(048) Nord_CO2_Intensity = Nord_CO2_Intensity_LOOKUP(Time)
Units: GTonC/year
(000)Time - Internally defined simulation time.
Causes:
(049) Nord_CO2_Intensity_LOOKUP( (1965, 0.519), (1975, 0.465), (1985, 0.421 ), (1995, 0.385), (2005, 0.356) , (2015, 0), (2025, 0.312), (2035, 0), (2045, 0), (2055, 0), (2065, 0), (2075 , 0.249), (2085, 0), (2095 , 0), (2105, 0) )
Units: GTonC/year
Uses:
(050) Nord_Emiss = Nord_Emiss_LOOKUP(Time)
Units: GTonC/year
Nordhaus' CO2 & CFC Emissions (Gt Carbon Equivalent) Uncontrolled scenario [Cowles, Table IV-4]. (000)Time - Internally defined simulation time.
Causes:
(051) Nord_Emiss_LOOKUP( (1965, 4.42), (1975, 5.89), (1985, 7.53), (1995, 9.28 ), (2005, 11.1), (2015, 0), (2025, 14.6), (2035, 0), (2045, 0), (2055, 0), (2065, 0), (2075, 22), (2085 , 0), (2095, 0), (2105, 0 ) )
Units: GTonC/year
Nordhaus' CO2 & CFC Emissions (Gt Carbon Equivalent) Uncontrolled scenario [Cowles, Table IV-4].
Uses:
(052) Nord_GHG_Reduction_Frac = IF_THEN_ELSE(Emissions_Scenario=1,No_Controls , IF_THEN_ELSE(Emissions_Scenario=2,Optimal_Controls, IF_THEN_ELSE(Emissions_Scenario=3,Emiss_Stabilization,Temp_Stabilization)))
Units: dmnl
Fraction of Greenhouse Gas Emissions Abated [mu(t)] (dimensionless) Selects one of three scenarios. [Cowles, pg. 20]
Causes:
(053) Optimal_Controls = Optimal_Controls_LOOKUP(Time)
Units: dmnl
Fraction of CO2 and CFC Emissions Controlled (dimensionless) Optimal control scenario. [Cowles, table IV-3] (000)Time - Internally defined simulation time.
Causes:
Uses:
(054) Optimal_Controls_LOOKUP( (1965, 0), (1975, 0), (1985, 0), (1995, 0.088 ), (2005, 0.096), (2015, 0.103 ), (2025, 0.111), (2035, 0.116), (2045, 0.12), (2055, 0.125), (2065, 0.129) , (2075, 0.134), (2085, 0.139 ), (2095, 0.143), (2105, 0.148) )
Units: dmnl
Fraction of CO2 and CFC Emissions Controlled (dimensionless) Optimal control scenario. [Cowles, table IV-3]
Uses:
(055) Preindustrial_CO2 = 5.9e+011
Units: TonC
Preindustrial atmospheric stock of carbon.
Uses:
(056) Rate_of_CO2_Transfer = 0.008333
Units: 1/year
Rate of Storage of Atmospheric Greenhouse Gases [delta-m] (1/year) Inverse yields average residence time of gases (120 years). Note that the validity and stability of this factor is highly questionable. [Cowles, pg. 21]
Uses:
(057) Temp_Stabilization = Temp_Stabilization_LOOKUP(Time)
Units: dmnl
Fraction of CO2 and CFC Emissions Controlled Stabilization of temperature. Estimated from graph. [Science, Fig. 1]. (000)Time - Internally defined simulation time.
Causes:
Uses:
(058) Temp_Stabilization_LOOKUP( (1965, 0), (1975, 0), (1985, 0), (1995, 0.45 ), (2005, 0.585), (2015, 0.72 ), (2025, 0.855), (2035, 0.99), (2045, 0.99), (2055, 0.97), (2065, 0.95), ( 2075, 0.95), (2085, 0.95) , (2095, 0.99), (2105, 0.92) )
Units: dmnl
Fraction of CO2 and CFC Emissions Controlled (dimensionless) Stabilization of temperature. Estimated from graph in [Science, Fig. 1].
Uses:
(059) A_UO_Heat_Cap = 44.248
Units: watt*year/DegreesC/(meter*meter)
Atmosphere & Upper Ocean Heat Capacity per Unit Area [1/R1] (W-yr/m^2/degrees C) Note: equals 1/0.0226 [Managing the Global Commons, pg. 21]
Uses:
(060) Atmos_UOcean_Temp = INTEG(Chg_A_UO_Temp, 0.2)
Units: DegreesC
Temperature of the Atmosphere and Upper Ocean [T] (degrees C) [Cowles, pg. 24]
Causes:
Uses:
(061) Chg_A_UO_Temp = (Radiative_Forcing-Feedback_Heating-Heat_Transfer)/A_UO_Heat_Cap
Units: DegreesC/year
Change in the Atmosphere & Upper Ocean Temperature (degrees C/yr) [Cowles, pg. 27]
Causes:
Uses:
(062) Chg_DO_Temp = Heat_Transfer/DO_Heat_Cap
Units: DegreesC/year
Change in the Deep Ocean Temperature (degrees C/yr) [Cowles, pg. 30]
Causes:
Uses:
(063) Climate_Damage_Frac = 1-1/(1+Climate_Damage_Scale*(Atmos_UOcean_Temp/ Reference_Temperature)^Climate_Damage_Nonlinearity )
Units: dmnl
Fraction of Output lost to combating Climate Change (1/Degrees C^2)
Causes:
Uses:
(064) Climate_Damage_Nonlinearity = 2
Units: dmnl
Nonlinearity of Climate Damage Cost Fraction [Theta2] (dimensionless) [Cowles, pg. 13 & 24]
Uses:
(065) Climate_Damage_Scale = 0.013
Units: dmnl
Climate Damage Fraction at Reference Temperature [part of Nordhaus' variable Theta1] (dimensionless) [Managing Global Commons, pg. 18 and 21]
Uses:
(066) Climate_Feedback_Param = 1.41
Units: watt/meter/meter/DegreesC
Climate Feedback Parameter [lambda] (W-m^2/degree C) The crucial climate sensitivity parameter - determines feedback effect from temperature increase. The Schneider-Thompson 2-stock model uses 1.33 [Cowles, Table III-B1]. [Managing Global Commons, pg. 21]
Uses:
(067) Deep_Ocean_Temp = INTEG(Chg_DO_Temp, 0.1)
Units: DegreesC
Temperature of the Deep Ocean [T*] (degrees C) [Cowles, pg. 24]
Causes:
Uses:
(068) DO_Heat_Cap = Heat_Capacity_Ratio*Heat_Trans_Coeff
Units: watt*year/DegreesC/meter/meter
Deep Ocean Heat Capacity per Unit Area [R2] (W-yr/m^2/degrees C) Note: Managing Global Commons uses .44*Heat_Trans_Coeff = 220; Cowles report uses 223.7 (page 30). [Managing Global Commons, pg. 21]
Causes:
Uses:
(069) Feedback_Heating = Atmos_UOcean_Temp*Climate_Feedback_Param
Units: watt/meter/meter
Feedback Heating (W/m^2) Additional heating of the atmosphere/upper ocean system from feedback effects of warming. [Cowles, pg. 27]
Causes:
Uses:
(070) Heat_Capacity_Ratio = 0.44
Units: watt/(meter*meter*DegreesC)
Ratio of Thermal Capacity of Deep Ocean to Heat Transfer Time Constant [R2/Tau12] [Managing Global Commons, pg. 21]
Uses:
(071) Heat_Trans_Coeff = 500
Units: year
Heat Transfer Coefficient [tau12] (years) Coefficient of heat transfer between the atmosphere & upper ocean and the deep ocean. May be interpreted as a mixing time constant. Schneider & Thompson use a slightly higher estimate of 550. [Cowles, pg. 31]
Uses:
(072) Heat_Transfer = Temp_Diff*DO_Heat_Cap/Heat_Trans_Coeff
Units: watt/meter/meter
Heat Transfer from the Atmosphere & Upper Ocean to the Deep Ocean
Causes:
Uses:
(073) Nord_Temp = Nord_Temp_LOOKUP(Time)
Units: DegreesC
Nordhaus' Atmospher & Upper Ocean Temperature Difference (degrees C) Uncontrolled scenario [Cowles, Table IV-5]. (000)Time - Internally defined simulation time.
Causes:
(074) Nord_Temp_LOOKUP( (1965, 0.2), (1975, 0.4), (1985, 0.58), (1995, 0.76 ), (2005, 0), (2015, 0), (2025, 1.4), (2035, 0), (2045, 0), (2055, 0), (2065, 0), (2075, 2.68), (2085, 0), (2095, 0), (2105, 3.4) )
Units: DegreesC
Nordhaus' Atmospher & Upper Ocean Temperature Difference (degrees C) Uncontrolled scenario [Cowles, Table IV-5].
Uses:
(075) Other_GHG_Rad_Forcing = Other_GHG_Rad_Forcing_LOOKUP(Time)
Units: watt/meter/meter
Radiative Forcing from Other GHGs (W/m^2) Additional surface warming from accumulation of other GHGs (NOx and Methane). [Table 4.9B, Managing Global Commons, pg. 73] (000)Time - Internally defined simulation time.
Causes:
Uses:
(076) Other_GHG_Rad_Forcing_LOOKUP( (1965, 0.41), (1975, 0.5), (1985, 0.6), (1995, 0.7), (2005, 0.78), (2015 , 0.87), (2025, 0.96), (2035, 1.05), (2045, 1.14), (2055, 1.2), (2065, 1.25 ), (2075, 1.29), (2085, 1.32 ), (2095, 1.35), (2105, 1.36) )
Units: watt/meter/meter
Radiative Forcing from Other GHGs (W/m^2) Additional surface warming from accumulation of other GHGs (NOx and Methane). [Table 4.9B, Managing Global Commons, pg. 73]
Uses:
(077) Radiative_Forcing = CO2_Rad_Forcing+Other_GHG_Rad_Forcing
Units: watt/meter/meter
Radiative Forcing from All GHGs (W/m^2) Additional surface warming from accumulation of CO2 & CFCs. [Cowles, Sec. III.F]
Causes:
Uses:
(078) Reference_Temperature = 3
Units: DegreesC
Reference Temperature for Calculation of Climate Damages [part of Nordhaus' variable theta1] [Managing Global Commons, pg. 18 and 21]
Uses:
(079) Temp_Diff = Atmos_UOcean_Temp-Deep_Ocean_Temp
Units: DegreesC
Temperature Difference between Upper and Deep Ocean (degrees C)
Causes:
Uses:
(080) FINAL_TIME = 2105
Units: year
Uses:
(081) Init_Policy_Times[T] = 1965,1980,1995,2000,2005,2015,2025,2050,2075,2100 ,2200
Units: year
Year of implementation of Tth policy.
Uses:
(082) INITIAL_TIME = 1965
Units: year
Uses: (000)Time - Internally defined simulation time.
Uses:
(083) Policy_Interval = max(0,(Time-Policy_Times[T1])/(Policy_Times[T2]-Policy_Times [T1]))
Units: dmnl
Fractional weight for policy value interpolation. (000)Time - Internally defined simulation time.
Causes:
Uses:
(084) Policy_Time_Shift[TL] = IF_THEN_ELSE(Time >= Policy_Times[T2],(Policy_Times [TU]-Policy_Times[TL])/TIME_STEP ,0) Policy_Time_Shift[TT] = IF_THEN_ELSE(Time &gt= Policy_Times[T2],(FINAL_TIME- Policy_Times[TT])/TIME_STEP ,0)
Units: year/year
Shift in policy time vector. (000)Time - Internally defined simulation time.
Causes:
Uses:
(085) Policy_Times[T] = INTEG(Policy_Time_Shift[T],Init_Policy_Times[T])
Units: year
Year of implementation of Tth policy, in reverse order.
Causes:
Uses:
(086) SAVEPER = 5
Units: year
(087) T : (T1-t11) Subscript for policy optimization arrays
(088) TIME_STEP = 0.5
Units: year
Uses:
(089) TL : (T1-T10) -> TU Lower subscripts for policy optimization arrays
(090) TT : t11 Top subscript of array.
(091) TU : (T2-t11) -> TL Upper subscripts for policy optimization arrays
(092) Actual_Energy_Share = Total_Energy_Expend/Gross_Output
Units: dmnl
Actual share of energy expenditures in output.
Causes:
(093) Auton_Energy_Tech_Gr_Rt[source] = 0
Units: 1/year
Autonomous energy technology growth rate (cost reducing).
Uses:
(094) Auton_Tech_Multiplier[source] = EXP(-Auton_Energy_Tech_Gr_Rt[source]* (Time - INITIAL_TIME))
Units: dmnl
Cumulative autonomous energy technology progress. (000)Time - Internally defined simulation time.
Causes:
Uses:
(095) Average_Price = SUM(Weighted_Price[source!])
Units: $/GJ
Weighted average price of physical energy.
Causes:
Uses:
(096) Cumulative_Production[source] = INTEG(Production[source],Init_Cum_Prod [source])
Units: GJ
Cumulative production of energy, by source.
Causes:
Uses:
(097) Depletion_Coeff[carbon] = 2 Depletion_Coeff[non_carbon] = 0 Depletion_Coeff[alt_carbon] = 0
Units: dmnl
Coefficient of depletion nonlinearity; higher values indicate more abrubt depletion.
Uses:
(098) Depletion_Multiplier[source] = Low_Lim_Depletion[source]+(1-Low_Lim_Depletion [source])/(1+(Cumulative_Production [source]/Reference_Resource[source])^Depletion_Coeff[source])
Units: dmnl
Effect of depletion on unit cost of energy production. A decreasing function of cumulative production, approaching a lower limit as cumulative production becomes large with respect to the reference cumulative production level.
Causes:
Uses:
(099) Energy_Demand = Energy_Serv_Demand/Energy_Serv_Ratio
Units: GJ/year
Energy demand in physical terms
Causes:
Uses:
(100) Energy_Expend[source] = Production[source]*Price[source]
Units: $/year
Energy expenditures (including taxes).
Causes:
Uses:
(101) Energy_Intensity_of_Output = Energy_Serv_Demand/Gross_Output
Units: GJ/$
Energy Intensity of Output
Causes:
(102) Energy_Price = Average_Price/Energy_Serv_Ratio
Units: $/GJ
Price of energy services.
Causes:
Uses:
(103) Energy_Serv_Ratio = SUM(Share_Exp[source!])^(1/Energy_Subst_Coeff)
Units: dmnl
Ratio of energy services output (CES aggregate) to physical energy input
Causes:
Uses:
(104) Energy_Subst_Coeff = (Energy_Subst_Elast-1)/Energy_Subst_Elast
Units: dmnl
Coefficient of substitution for CES aggregate
Causes:
Uses:
Units: dmnl
Elasticity of substitution among energy sources.
Uses:
(106) Indicated_Share[source] = Price_Exp[source]/SUM(Price_Exp[source!])
Units: dmnl
Indicated share of energy sources in total output
Causes:
Uses:
(107) Init_Cum_Prod[carbon] = 5e+012 Init_Cum_Prod[non_carbon] = 2.5e+011 Init_Cum_Prod[alt_carbon] = 5e+011
Units: GJ
Initial cumulative production, by source.
Uses:
(108) Learning_Coeff[source] = LOG(1-Learning_Rate[source],2)
Units: dmnl
Learning curve coefficient.
Causes:
Uses:
(109) Learning_Rate[source] = 0.1
Units: dmnl
Learning rate, expressed as fractional reduction per doubling of experience.
Uses:
(110) Low_Lim_Depletion[carbon] = 0 Low_Lim_Depletion[non_carbon] = 1 Low_Lim_Depletion[alt_carbon] = 1
Units: dmnl
Lower limit to depletion effect Set to .25 for carbon energy, implying that a total shift to coal and non-conventional carbon fuels would involve a quadrupling of cost. Value for non-carbon energy is 1, indicating that there is no depletion effect.
Uses:
(111) Price[source] = Energy_Carbon_Tax[source]+Unit_Cost[source]
Units: $/GJ
Energy price.
Causes:
Uses:
(112) Price_Exp[source] = (Price[source]/Std_Price/Share_Coeff[source])^(-Energy_Subst_Elast )
Units: dmnl
Contribution of source prices to aggregate price.
Causes:
Uses:
(113) Production[source] = Energy_Demand*Indicated_Share[source]
Units: GJ/year
Physical energy production.
Causes:
Uses:
(114) Reference_Price[carbon] = 0.9 Reference_Price[non_carbon] = 5.4 Reference_Price[alt_carbon] = 3.6
Units: $/GJ
Initial or reference price of energy sources.
Uses:
(115) Reference_Resource[carbon] = 6e+013 Reference_Resource[non_carbon] = 1 Reference_Resource[alt_carbon] = 6e+014
Units: GJ
Initial resources of energy. Alt carbon value corresponds with total fossil resources, while carbon value is approximately 2x oil & gas resources.
Uses:
Units: dmnl
Energy share coefficients, assumed equal for each source, so that initial share differences must be attributed to price.
Uses:
(117) Share_Exp[source] = Share_Coeff[source]*Indicated_Share[source]^Energy_Subst_Coeff
Units: dmnl
Weighted contribution of energy sources to energy services, for calculation of ratio of physical energy input to energy services output.
Causes:
Uses:
(118) source : carbon,non_carbon,alt_carbon Energy sources.
(119) Std_Price = 1
Units: $/GJ
Reference price (for unit consistency).
Uses:
(120) Technology_Multiplier[source] = (Cumulative_Production[source]/Init_Cum_Prod [source])^Learning_Coeff [ source]
Units: dmnl
Effect of learning on unit costs.
Causes:
Uses:
(121) Total_Energy_Expend = SUM(Energy_Expend[source!])
Units: $/year
Total expenditures on energy production, including taxes.
Causes:
Uses:
(122) Total_Energy_Prod = SUM(Production[source!])
Units: GJ/year
Total physical energy production.
Causes:
(123) Unit_Cost[source] = Reference_Price[source]/Depletion_Multiplier[source ] *Technology_Multiplier[source]*Auton_Tech_Multiplier[source]
Units: $/GJ
Unit cost of energy sources, dependent on technology, depletion, and initial price.
Causes:
Uses:
(124) Weighted_Price[source] = Indicated_Share[source]*Price[source]
Units: $/GJ
Weighted contribution of energy sources to average energy price.
Causes:
Uses:
(125) Behav_Inequal_Aversion = 1
Units: dmnl
Rate of inequality aversion characterizing behavior.
Uses:
(126) Behav_Invest_Frac = INTEG(Chg_Invest_Frac,0.22)
Units: dmnl
Investment fraction indicated by behavioral savings rule.
Causes:
Uses:
(127) Behav_Time_Pref = 0.03
Units: 1/year
Rate of time preference characterizing behavior.
Uses:
(128) Chg_Invest_Frac = (Desired_Invest_Frac-Behav_Invest_Frac)/Invest_Adj_Time
Units: 1/year
Rate of change of investment fraction (savings rate).
Causes:
Uses:
(129) Desired_Invest_Frac = Behav_Invest_Frac*(Desired_Return_on_Capital/Marg_Return_Capital )^Invest_Adj_Coeff
Units: dmnl
Desired savings rate, anchored to current savings rate and adjusted for prevailing returns.
Causes:
Uses:
(130) Desired_Return_on_Capital = Behav_Inequal_Aversion*Perceived_Growth_Rt +Behav_Time_Pref
Units: 1/year
Desired rate of return, assuming Ramsey equilibrium optimal investment conditions, in which interest rate = elast of marginal utility * growth rate + discount rate
Causes:
Uses:
(131) Growth_Trend_Avg_Time = 3
Units: year
Averaging time for perception of growth trend.
Uses:
(132) Init_Growth_Rt = 0.045
Units: 1/year
Initial perceived economic growth rate.
Uses:
(133) Init_Invest_Fracs[T] = 0.219,0.206,0.196,0.194,0.192,0.19,0.182,0.175 ,0.171,0.168,0.168
Units: dmnl
Investment fractions at time T. Default values from Nordhaus. Generally replaced by optimization.
Uses:
Units: dmnl
Coefficient of adjustment of desired investment fraction.
Uses:
Units: year
Savings rate adjustment time.
Uses:
(136) Invest_Fracs[T] = INTEG(Invest_Shift[T],Init_Invest_Fracs[T])
Units: dmnl
Investment Fractions at policy time T.
Causes:
Uses:
(137) Invest_Shift[TL] = IF_THEN_ELSE(Time >= Policy_Times[T2],(Invest_Fracs [TU]-Invest_Fracs[TL])/TIME_STEP ,0) Invest_Shift[TT] = 0
Units: 1/year
Shift in policy time vector. Top element (last time period) stays fixed. (000)Time - Internally defined simulation time.
Causes:
Uses:
(138) Investment_Frac = IF_THEN_ELSE(Investment_Switch=1,Optimal_Invest_Frac , IF_THEN_ELSE(Investment_Switch=0,Nord_Investment_Frac,Behav_Invest_Frac))
Units: dmnl
Fraction of Output Invested (savings rate)
Causes:
Uses:
(139) Investment_Frac_LOOKUP( (1965, 0.219), (1975, 0.21), (1985, 0.202), ( 1995, 0.196), (2005, 0.193), (2015 , 0.19), (2025, 0.182), (2035, 0.18), (2045, 0.178), (2055, 0.175), (2065, 0.173), (2075, 0.171), (2085 , 0.17), (2095, 0.168), (2105, 0.168) )
Units: dmnl
Fraction of Output allocated to Investment (dimensionless) Time path derived from results of optimization reported in [Cowles, Table IV-2, Optimal]. Intermediate points interpolated linearly. Points after 2075 estimated from [Cowles, Fig. IV-5].
Uses:
Units: dmnl
0 = Nordhaus reference path, 1 = Path from optimization, 2 = Behavioral
Uses:
(141) Net_Investment = Investment-Depreciation
Units: $/year
Net Investment Investment less depreciation
Causes:
Uses:
(142) Net_Savings_Rate = Net_Investment/Output
Units: dmnl
Net Savings Rate Equal to the ratio of net investment to output.
Causes:
(143) Nord_Investment_Frac = Investment_Frac_LOOKUP(Time)
Units: dmnl
Fraction of Output allocated to Investment (dimensionless) Time path derived from results of optimization reported in [Cowles, Table IV-2, Optimal]. Intermediate points interpolated linearly. Points after 2075 estimated from [Cowles, Fig. IV-5]. (000)Time - Internally defined simulation time.
Causes:
Uses:
(144) Optimal_Invest_Frac = Invest_Fracs[T2]*Policy_Interval+Invest_Fracs[T1 ]*(1-Policy_Interval)
Units: dmnl
Investment Fraction derived from optimization.
Causes:
Uses:
(145) Perceived_Growth_Rt = TREND(Output,Growth_Trend_Avg_Time,Init_Growth_Rt )
Units: 1/year
Perceived economic growth rate.
Causes:
Uses:
(146) Atmospheric_Retention = (Emissions-Diffusion_Flux[layer1]-Flux_AtmMix_to_Biosphere )/Emissions
Units: dmnl
Average atmospheric retention of CO2
Causes:
Units: year
Residence time of CO2 in the biosphere. Trees and soils have longer residence times.
Uses:
(148) Biostim_Coeff = 0.3
Units: dmnl
Sensitivity of primary production to changes in atmospheric CO2 concentration.
Uses:
(149) bottom5 : (layer6-layer10) Bottom 5 (thick) ocean layers.
(150) Buffer_Factor = 10
Units: dmnl
Revelle or Buffer factor; relates increase in ocean CO2 partial pressure to ocean carbon concentration.
Uses:
(151) CO2_in_AtmMix = INTEG(Emissions-Diffusion_Flux[layer1]-Flux_AtmMix_to_Biosphere , Init_CO2_in_Atm+Init_CO2_in_Mixed_Layer)
Units: TonC
CO2 in atmosphere and mixed ocean layer.
Causes:
Uses:
(152) CO2_in_Atmosphere = (CO2_in_AtmMix-Init_CO2_in_Mixed_Layer*(1-1/Buffer_Factor )) /(1+Init_CO2_in_Mixed_Layer/Init_CO2_in_Atm/Buffer_Factor)
Units: TonC
CO2 in atmosphere, from equilibrium solution to more complex model with explicit atmosphere and mixed layer stocks.
Causes:
Uses:
(153) CO2_in_Biosphere = INTEG(Flux_AtmMix_to_Biosphere,Init_NPP*Biosphere_Res_Time )
Units: TonC
CO2 in terrestrial biota.
Causes:
Uses:
(154) CO2_in_Deep_Ocean[upper] = INTEG(Diffusion_Flux[upper]-Diffusion_Flux [lower], Init_CO2_in_Deep_Ocean*Thickness[upper]/Deep_Ocean_Depth) CO2_in_Deep_Ocean[layer10] = INTEG(Diffusion_Flux[layer10], Init_CO2_in_Deep_Ocean*Thickness[layer10]/Deep_Ocean_Depth)
Units: TonC
CO2 in deep ocean, by layer.
Causes:
Uses:
(155) CO2_in_Mixed_Layer = CO2_in_AtmMix-CO2_in_Atmosphere
Units: TonC
CO2 in mixed ocean layer, from equilibrium solution to more complex model with explicit atmosphere and mixed layer stocks.
Causes:
Uses:
(156) Concentration[layers] = CO2_in_Deep_Ocean[layers]/Thickness[layers]
Units: TonC/meter
CO2 concentration in deep ocean layers.
Causes:
Uses:
(157) Deep_Ocean_Depth = 3800
Units: meter
Total thickness of the deep ocean.
Uses:
(158) Diffusion_Flux[layer1] = (CO2_in_Mixed_Layer/Mixed_Depth-Concentration [layer1])*Eddy_Diff_Coeff *2/(Mixed_Depth+Thickness[layer1]) Diffusion_Flux[lower] = (Concentration[upper]-Concentration[lower])*Eddy_Diff_Coeff *2/(Thickness[upper]+Thickness[lower])
Units: TonC/year
Diffusion flux of CO2 between ocean layers.
Causes:
Uses:
(159) Eddy_Diff_Coeff = 4000
Units: meter*meter/year
Ocean diffusion flux coefficient.
Uses:
(160) Emissions = CO2_Emissions
Units: TonC/year
Total anthropogenic CO2 emissions to the atmosphere.
Causes:
Uses:
(161) Flux_AtmMix_to_Biosphere = Init_NPP*(CO2_in_Atmosphere/Preindustrial_CO2 )^Biostim_Coeff - CO2_in_Biosphere/Biosphere_Res_Time
Units: TonC/year
Net flow of carbon from the atmosphere and mixed layer to the biosphere.
Causes:
Uses:
(162) Init_CO2_in_Atm =6.77e+011
Units: TonC
CO2 in Atmosphere in 1965 (Preindustrial level is 5.9e11)
Uses:
(163) Init_CO2_in_Deep_Ocean = Init_CO2_in_Mixed_Layer*Deep_Ocean_Depth/Mixed_Depth
Units: TonC
Initial CO2 in deep ocean
Causes:
Uses:
(164) Init_CO2_in_Mixed_Layer = 7.678e+011
Units: TonC
Initial CO2 in mixed ocean layer
Uses:
(165) Init_NPP = 6e+010
Units: TonC/year
Initial net primary production
Uses:
(166) layers : (layer1-layer10) Deep ocean layers.
(167) lower : (layer2-layer10) -> upper Lower 9 deep ocean layers.
(168) Mixed_Depth = 75
Units: meter
Depth of mixed ocean layer.
Uses:
(169) Thickness[top5] = 200 Thickness[bottom5] = 560
Units: meter
Layers chosen to be relatively thick, as fast dynamics are not of interest.
Uses:
(170) top5 : (layer1-layer5) Top 5 (thin) ocean layers.
(171) upper : (layer1-layer9) -> lower Upper 9 deep ocean layers.
(172) Decline_Nonenergy_CO2_Intens = Nonenergy_CO2_Int_of_Output*Nonenergy_CO2_Intens_Decline_Rt
Units: TonC/$/year
Decline of GHG Intensity of Output (tons carbon equivalent/$/year) [Cowles, pg. 20]
Causes:
Uses:
(173) GHG_Reduction_Frac = IF_THEN_ELSE(Carbon_Tax > 0, MIN(1,(Carbon_Tax*Nonenergy_CO2_Int_of_Output/Red_Cost_Scale/Red_Cost_Nonlinearity ) ^(1/(Red_Cost_Nonlinearity-1))), 0)
Units: dmnl
Fraction of Nonenergy Greenhouse Gas Emissions Abated Set so that the marginal productivity of nonenergy carbon equals the carbon tax. IF statement added to prevent floating point error on Windows platform.
Causes:
Uses:
(174) Nonenergy_CO2_Emiss = (1-GHG_Reduction_Frac)*Nonenergy_CO2_Int_of_Output *Gross_Output
Units: TonC/year
Greenhouse Gas Emissions [E(t)] (tons carbon equivalent/year) [Cowles, pg. 20]
Causes:
Uses:
(175) Nonenergy_CO2_Int_of_Output = INTEG(- Decline_Nonenergy_CO2_Intens, Ref_Nonenergy_CO2_Emiss /Output_in_1965 )
Units: TonC/$
Greenhouse Gas Intensity of Output [sigma(t)] (tons carbon equivalent/$) Conflicts with value reported on Cowles, pg. 24: .5368*.9875^(TIME-1990)/1000 = .7352/1000 [Managing Global Commons, pg. 21]
Causes:
Uses:
(176) Nonenergy_CO2_Intens_Dec_Rt_Decline_Rt = Nonenergy_CO2_Intens_Decline_Rt *Fact_Prod_Gr_Rt_Dec_Rt
Units: 1/year/year
Rate of decline of nonenergy CO2 intensity decline rate (2nd derivative).
Causes:
Uses:
(177) Nonenergy_CO2_Intens_Decline_Rt = INTEG(- Nonenergy_CO2_Intens_Dec_Rt_Decline_Rt , 0.01168)
Units: 1/year
Rate of Decline of Greenhouse Gas Intensity of Output [g-sigma] (1/year) Note that Nordhaus decompounds the decadal rate of .1168 to yield an annual rate of .0125; I have simply divided by 10 to convert the decadal rate to an annual rate. [Managing Global Commons, pg. 21]
Causes:
Uses:
(178) Nonenergy_CO2_Red_Cost = Gross_Output*Nonenergy_CO2_Red_Cost_Frac
Units: $/year
Cost of nonenergy CO2 emissions abatement.
Causes:
Uses:
(179) Nonenergy_CO2_Red_Cost_Frac = IF_THEN_ELSE(GHG_Reduction_Frac>0, Red_Cost_Scale*GHG_Reduction_Frac^Red_Cost_Nonlinearity, 0)
Units: dmnl
Fraction of Output devoted to cost of GHG emissions reductions (dimensionless) IF statement added to prevent floating point error on Windows platform.
Causes:
Uses:
(180) Red_Cost_Nonlinearity = 2.887
Units: dmnl
Nonlinearity of GHG Reduction Cost [b2] (dimensionless) [Cowles, pg. 13 & 24]
Uses:
(181) Red_Cost_Scale = 0.0211
Units: dmnl
Scale of Nonenergy CO2 Reduction Cost Equals Nordhaus' figure of .0686 multiplied by the initial share of nonenergy emissions in total emissions.
Uses:
(182) Ref_Nonenergy_CO2_Emiss = 1.36e+009
Units: TonC/year
Uses:
(183) Capital_Elast_Output = 0.25
Units: dmnl
Capital Elasticity of Output [alpha] (dimensionless) Derived from share of capital in national income. [Cowles, pg. 17]
Uses:
(184) Climate_Damage_Cost = Climate_Damage_Frac*Gross_Output
Units: $/year
Output lost or diverted due to climate change.
Causes:
Uses:
(185) Consumption = Output-Investment
Units: $/year
Consumption ($/year) Output less investment (savings).
Causes:
Uses:
(186) Consumption_per_Cap = Output/Population
Units: $/person/year
Consumption of goods per Capita ($/person/year)
Causes:
(187) Eff_Consumption_per_Cap = Effective_Consumption/Population
Units: $/person/year
Consumption of goods less climate damages per Capita ($/person/year)
Causes:
Uses:
(188) Effective_Consumption = Consumption-Intangible_Damage_Cost
Units: $/year
Consumption of goods less losses from environmental damage due to climate change.
Causes:
Uses:
(189) Fact_Prod_Gr_Rt_Dec_Rt = 0.011
Units: 1/year
Rate of Decline of Factor Productivity Growth Rate [delta-A] (1/year/year) Factor productivity growth rate declines 11% per decade. [Cowles, pg. 18]
Uses:
(190) Fact_Prod_Gr_Rt_Decline_Rt = Fact_Prod_Growth_Rt*Fact_Prod_Gr_Rt_Dec_Rt
Units: 1/year/year
Decline of Factor Productivity Growth Rate (1/year/year)
Causes:
Uses:
(191) Fact_Prod_Growth_Rt = INTEG(- Fact_Prod_Gr_Rt_Decline_Rt, 0.015)
Units: 1/year
Growth Rate of Factor Productivity [gA(t)] (1/year) Growth rate declines over time. Value reported in [Cowles, pg. 17]: .0152 for period 1965-1987, matches statement in [Science, pg. 1317] that average was 1.3% from 1965-1989, with an 11%/decade rate of decline. Note that Nordhaus decompounds the decadal rate of .150 to yield an annual rate of .014; I have simply divided by 10 to convert the decadal rate to an annual rate. [Managing Global Commons, pg. 21] [Managing the Global Commons, pg. 21]
Causes:
Uses:
(192) Fact_Prod_Incr_Rt = Factor_Productivity*Fact_Prod_Growth_Rt
Units: 1/year
Change in Factor Productivity (1/year)
Causes:
Uses:
(193) Factor_Productivity = INTEG(Fact_Prod_Incr_Rt, 1)
Units: dmnl
Total Factor Productivity [A(t)] (dimensionless) May be interpreted as level of technology. [Cowles pg. 17]
Causes:
Uses:
(194) Frac_Clim_Dam_Tangible = 1
Units: dmnl
Fraction of climate change damage costs which are tangible (that is, those which appear on national accounts and may be substituted with other goods).
Uses:
(195) Gross_Output = Output_in_1965*Factor_Productivity*(Effective_Capital/ INIT(Effective_Capital))^Capital_Elast_Output *(Population/INIT(Population))^(1-Capital_Elast_Output)
Units: $/year
Reference Output before effects of climate damage and emissions abatement are considered
Causes:
Uses: