The land conversion cost module calculates costs for the conversion from one land type to another (e.g. conversion from forest to cropland). Land conversion plays an important role for the overall model dynamics, in particular in terms of CO2 emissions from land-use change. Expansion of agricultural land is one of the major options in the model to increase agricultural production, besides yield increases (13_tc, 14_yields) and trade (21_trade).
| Description | Unit | A | |
|---|---|---|---|
| pm_interest (i) |
Current interest rate in each region | \(\%/yr\) | x |
| vm_carbon_stock_reduction (j, land, c_pools) |
Reduction in carbon stocks compared to previous time step | \(10^6 tC/time step\) | x |
| vm_landexpansion (j, land) |
Land expansion | \(10^6 ha\) | x |
| Description | Unit | |
|---|---|---|
| vm_cost_landcon (j, land) |
Land conversion costs | \(10^6 USD_{05MER}/yr\) |
In the global_static_aug18 realization, per hectare land conversion costs are separated into costs for expansion of cropland, pasture and forestry (establishment costs) and costs for clearing of primary forest, secondary forest and other natural land (clearing costs). We assume a global cost factor of 8000 USD/ha (static over time) for establishment of managed land. For clearing of natural vegetation we assume a global static cost factor of 5 USD/tC (based on Kreidenweis et al. (2018)).
Land establishment costs apply on expansion of cropland, pasture and forestry. Land clearing costs apply on reduction of carbon stock in primary forest, secondary forest and other natural land. The sum of land establishment and land clearing costs in the current time step is multiplied with an annuity factor to distribute these costs over time.
\[\begin{multline*} v39\_cost\_landcon\_annuity(j2,land) = \left(vm\_landexpansion(j2,land) \cdot i39\_cost\_establish(land) + vm\_carbon\_stock\_reduction(j2,land,"vegc") \cdot i39\_cost\_clearing(land)\right) \cdot \sum_{cell(i2,j2)}\left(\frac{pm\_interest(i2)}{\left(1+pm\_interest(i2)\right)}\right) \end{multline*}\]
Land conversion costs in the current time step consist of the annuitized costs for land conversion in the current time step v39_cost_landcon_annuity and the land conversion costs from the past pc39_cost_landcon_past.
\[\begin{multline*} vm\_cost\_landcon(j2,land) = v39\_cost\_landcon\_annuity(j2,land) + pc39\_cost\_landcon\_past(j2,land) \end{multline*}\]
Limitations Data availability for land conversion costs is very limited.
| Description | Unit | A | |
|---|---|---|---|
| i39_cost_clearing (land) |
Global land clearing costs | \(USD_{05MER}/ton C\) | x |
| i39_cost_establish (land) |
Global land establishment costs | \(USD_{05MER}/hectare\) | x |
| p39_cost_landcon_past (t, j, land) |
Costs for landconversion from the past | \(10^6 USD_{05MER}/yr\) | x |
| pc39_cost_landcon_past (j, land) |
Costs for landconversion from the past in the current time step | \(10^6 USD_{05MER}/yr\) | x |
| q39_cost_landcon (j, land) |
Calculation of cellular landconversion costs | \(10^6 USD_{05MER}/yr\) | x |
| q39_cost_landcon_annuity (j, land) |
Calculation of cellular annuity costs of landconversion | \(10^6 USD_{05MER}/yr\) | x |
| s39_cost_clearing | Global land clearing costs | \(USD_{05MER}/ton C\) | x |
| s39_cost_establish | Global land establishment costs | \(USD_{05MER}/hectare\) | x |
| v39_cost_landcon_annuity (j, land) |
Annuity costs of landconversion in the current timestep | \(10^6 USD_{05MER}/yr\) | x |
| description | |
|---|---|
| c_pools | Carbon pools |
| cell(i, j) | number of LPJ cells per region i |
| i | all economic regions |
| i2(i) | World regions (dynamic set) |
| j | number of LPJ cells |
| j2(j) | Spatial Clusters (dynamic set) |
| land | Land pools |
| land_clearing39(land) | Natural vegetation land pools |
| land_establish39(land) | Managed land pools |
| t(t_all) | Simulated time periods |
| type | GAMS variable attribute used for the output |
Florian Humpenöder, Jan Philipp Dietrich, Ulrich Kreidenweis
10_land, 11_costs, 12_interest_rate, 52_carbon
Kreidenweis, Ulrich, Florian Humpenöder, Laura Kehoe, Tobias Kuemmerle, Benjamin Leon Bodirsky, Hermann Lotze-Campen, and Alexander Popp. 2018. “Pasture Intensification Is Insufficient to Relieve Pressure on Conservation Priority Areas in Open Agricultural Markets.” Global Change Biology 0 (0). https://doi.org/10.1111/gcb.14272.