The carbon module provides carbon density information for different land types.
Interface plot missing!
| Description | Unit | A | |
|---|---|---|---|
| fm_aboveground_fraction (land_timber) |
Aboveground fraction of total biomass | \(1\) | x |
| fm_ipcc_bef (clcl) |
IPCC biomass expansion factor BEF | \(1\) | x |
| im_forest_ageclass (j, ac) |
Forest area in 5-year age-classes based on GFAD | \(10^6 ha\) | x |
| pcm_carbon_stock (j, land, c_pools, stockType) |
Carbon stock in vegetation soil and litter for different land types | \(10^6 tC\) | x |
| pm_climate_class (j, clcl) |
Koeppen-Geiger climate classification on the simulation cluster level | \(1\) | x |
| pm_land_plantation (j, ac) |
Plantation land by age class for growing stock calibration | \(10^6 ha\) | x |
| sm_carbon_fraction | Carbon fraction of dry matter | \(tC/tDM\) | x |
| sm_fix_cc | year until which all parameters affected by cc are fixed to historical values | \(year\) | x |
| vm_carbon_stock (j, land, c_pools, stockType) |
Carbon stock in vegetation soil and litter for different land types | \(10^6 tC\) | x |
| vm_emissions_reg (i, emis_source, pollutants) |
Regional emissions by source and gas after technical mitigation N CH4 C | \(Tg/yr\) | x |
| Description | Unit | |
|---|---|---|
| fm_carbon_density (t_all, j, land, c_pools) |
LPJmL carbon density for land and carbon pools | \(tC/ha\) |
| im_vol_conv (i) |
Regional basic wood density | \(tDM/m3\) |
| pm_carbon_density_other_ac (t_all, j, ac, ag_pools) |
Vegetation other land carbon density for age classes and carbon pools | \(tC/ha\) |
| pm_carbon_density_plantation_ac (t_all, j, ac, ag_pools) |
Vegetation plantation carbon density for age classes and carbon pools | \(tC/ha\) |
| pm_carbon_density_plantation_ac_uncalib (t_all, j, ac, ag_pools) |
Vegetation plantation carbon density uncalibrated | \(tC/ha\) |
| pm_carbon_density_secdforest_ac (t_all, j, ac, ag_pools) |
Vegetation secondary forest carbon density for age classes and carbon pools | \(tC/ha\) |
| pm_carbon_density_secdforest_ac_uncalib (t_all, j, ac, ag_pools) |
Vegetation secondary forest carbon density uncalibrated | \(tC/ha\) |
This realization provides carbon density information on cellular level to all land modules ([30_crop], 31_past, 32_forestry, 34_urban and 35_natveg). The realization provides carbon density for different age-classes, based on a Chapman-Richards growth model, to the land modules 32_forestry and 35_natveg Braakhekke et al. (2019).
When enabled (s52_growingstock_calib = 1), the growth
rate parameter k in the Chapman-Richards equation is
calibrated per region via bisection to match FAO FRA 2025 growing stock
targets. Secdforest k is calibrated to FRA NRF (naturally
regenerating forest) growing stock using the full GFAD age distribution.
Plantation k is calibrated to FRA plantation growing stock.
Uncalibrated growth curves are preserved for use by afforestation and
NDC forest commitments, which represent new establishment rather than
existing managed forests.
Actual CO2 emissions are calculated based on changes in carbon stocks
between timesteps in the interface vm_carbon_stock.
\[\begin{multline*} vm\_emissions\_reg(i2,emis\_oneoff,"co2\_c") = \sum_{cell(i2,j2),emis\_land(emis\_oneoff,land,c\_pools)}\left(\frac{ \left(pcm\_carbon\_stock(j2,land,c\_pools,"actual") - vm\_carbon\_stock(j2,land,c\_pools,"actual")\right)}{m\_timestep\_length}\right) \end{multline*}\]
Growing stock calibration of secdforest and plantation growth curves. For each region, find k (growth rate in Chapman-Richards equation) such that the area-weighted growing stock matches FRA targets. - Secdforest: uses GFAD age distribution (im_forest_ageclass from module 28) - Plantations: assumes uniform age distribution across all age classes
This runs in preloop (after module 28 preloop has populated im_forest_ageclass).
Conversion chain: C_density (tC/ha) -> GS (m3/ha): GS = C_density / carbon_fraction * aboveground_fraction / BEF / D where D = basic wood density (tDM/m3), BEF = biomass expansion factor
Limitations Carbon density asymptote (C_max) comes from LPJmL potential vegetation and may exceed observed growing stock in degraded tropical forests.
| Description | Unit | A | |
|---|---|---|---|
| f52_fra_nrf_gs (i) |
FRA growing stock target for naturally regenerating forests | \(m3/ha\) | x |
| f52_fra_pla_gs (i) |
FRA growing stock target for plantations | \(m3/ha\) | x |
| f52_growth_par (clcl, chap_par, forest_type) |
Parameters for chapman-richards equation | \(1\) | x |
| f52_land_carbon_sink (t_all, i, rcp52) |
Land carbon sink adjustment factors from Grassi et al 2021 | \(GtCO2/year\) | x |
| f52_volumetric_conversion (clcl) |
Basic wood density by climate class | \(tDM/m3\) | x |
| i52_bef_avg (i) |
Regional average biomass expansion factor | \(1\) | x |
| i52_gs_current (i) |
Current area-weighted growing stock for natural forest calibration | \(m3/ha\) | x |
| i52_gs_current_plant (i) |
Current area-weighted growing stock for plantations | \(m3/ha\) | x |
| i52_k_calib_plant (i) |
Calibrated growth rate k for plantations | \(1\) | x |
| i52_k_calib_secdf (i) |
Calibrated growth rate k for secdforest | \(1\) | x |
| i52_k_high (i) |
Upper bound for bisection of growth rate k | \(1\) | x |
| i52_k_low (i) |
Lower bound for bisection of growth rate k | \(1\) | x |
| i52_land_carbon_sink (t_all, i) |
Land carbon sink adjustment factors from Grassi et al 2021 | \(GtCO2/year\) | x |
| i52_m_avg_natveg (i) |
Region-average shape parameter m for natveg | \(1\) | x |
| i52_m_avg_plant (i) |
Region-average shape parameter m for plantations | \(1\) | x |
| pc52_carbon_density_start (t_all, j, ag_pools) |
Vegetation carbon density for new land in other land pool | \(tC/ha\) | x |
| q52_emis_co2_actual (i, emis_oneoff) |
Calculation of annual CO2 emissions | \(Tg/yr\) | x |
| s52_growingstock_calib | Switch for growing stock calibration of secdforest growth curves 1=on 0=off | \(1\) | x |
| s52_k_high_plant | Upper bound for plantation k bisection - slightly higher than secdf because plantations can exceed natural growth rates | \(1\) | x |
| s52_k_high_secdf | Upper bound for secdforest k bisection - kept low because FRA NRF growing stock is below LPJmL potential in most regions | \(1\) | x |
| description | |
|---|---|
| ac | Age classes |
| age | Population age groups |
| ag_pools(c_pools) | Above ground carbon pools |
| cell(i, j) | number of LPJ cells per region i |
| chap_par | Chapman-richards parameters |
| clcl | climate classification types |
| c_pools | Carbon pools |
| emis_land(emis_oneoff, land, c_pools) | Mapping between land and carbon pools |
| emis_oneoff(emis_source) | oneoff emission sources |
| emis_source | Emission sources |
| factors | factors included in factor requirements |
| forest_type | forest type |
| i | all economic regions |
| i2(i) | World regions (dynamic set) |
| iter52 | bisection iterations for growth curve calibration |
| j | number of LPJ cells |
| j2(j) | Spatial Clusters (dynamic set) |
| k(kall) | Primary products |
| land | Land pools |
| land_forest(land_timber) | Forested land pools |
| land_timber(land) | land from which timber can be taken away |
| pollutants(pollutants_all) | subset of pollutants_all that can be taxed |
| rcp52 | climate change impact sceanrios |
| stockType | Carbon stock types |
| t_all(t_ext) | 5-year time periods |
| t(t_all) | Simulated time periods |
| type | GAMS variable attribute used for the output |
Benjamin Leon Bodirsky, Florian Humpenoeder, Abhijeet Mishra
09_drivers, 14_yields, 28_ageclass, 29_cropland, 30_croparea, 31_past, 32_forestry, 35_natveg, 45_climate, 56_ghg_policy, 59_som, 73_timber