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 (t_all, i) |
Interest rate in each region and timestep | \(\%/yr\) | 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.
\[\begin{multline*} vm\_cost\_landcon(j2,land) = \left(vm\_landexpansion(j2,land) \cdot i39\_cost\_establish(land) + vm\_carbon\_stock\_reduction(j2,land,"vegc") \cdot i39\_cost\_clearing(land)\right) \cdot \sum_{cell(i2,j2),ct}\left(\frac{pm\_interest(ct,i2)}{\left(1+pm\_interest(ct,i2)\right)}\right) \end{multline*}\]
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 |
| q39_cost_landcon (j, land) |
Calculation of cellular landconversion costs | \(10^6 USD_{05MER}/yr\) | x |
| s39_cost_clearing | Global land clearing costs | \(USD_{05MER}/ton C\) | x |
| s39_cost_establish | Global land establishment costs | \(USD_{05MER}/hectare\) | x |
| description | |
|---|---|
| c_pools | Carbon pools |
| cell(i, j) | number of LPJ cells per region i |
| ct(t) | Current time period |
| 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_all(t_ext) | 5-year time periods |
| 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.