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_landexpansion (j, land) |
Land expansion | \(10^6 ha\) | x |
| vm_landreduction (j, land) |
Land reduction | \(10^6 ha\) | x |
| Description | Unit | |
|---|---|---|
| vm_cost_landcon (j, land) |
Costs for land expansion and reduction | \(10^6 USD_{05MER}/yr\) |
This realization accounts for land conversion costs of cropland, pasture, forestry and urban land. Costs for expansion of pasture, forestry and urban land are global and static over time. For cropland, a regional and time-dependent calibration factor is applied on global costs for land expansion, complemented by a reward for cropland reduction in selected regions, for a better match of regional cropland in 2015 with historic data. The calibration factor for costs of cropland expansion is lifted to a minium of 1 in all regions by 2050.
The sum of costs for land expansion and land reduction is multiplied with an annuity factor to distribute these costs over time.
\[\begin{multline*} vm\_cost\_landcon(j2,land) = \left(vm\_landexpansion(j2,land) \cdot \sum_{ct,cell(i2,j2)} i39\_cost\_establish(ct,i2,land) - vm\_landreduction(j2,land) \cdot \sum_{ct,cell(i2,j2)} i39\_reward\_reduction(ct,i2,land)\right) \cdot \sum_{cell(i2,j2),ct}\left(\frac{pm\_interest(ct,i2)}{\left(1+pm\_interest(ct,i2)\right)}\right) \end{multline*}\]
Limitations Data availability for land conversion costs is very limited.
| Description | Unit | A | |
|---|---|---|---|
| f39_calib (t_all, i, type39) |
Calibration factor for costs of cropland expansion | \(1\) | x |
| i39_calib (t, i, type39) |
Calibration factor for costs of cropland expansion and rewards for cropland reduction | \(1\) | x |
| i39_cost_establish (t, i, land) |
Land expansion costs | \(USD_{05MER}/hectare\) | x |
| i39_reward_reduction (t, i, land) |
Reward for land reduction | \(USD_{05MER}/hectare\) | x |
| q39_cost_landcon (j, land) |
Calculation of cellular landconversion costs | \(10^6 USD_{05MER}/yr\) | x |
| s39_cost_establish_crop | Cost for cropland expansion before calibration | \(USD_{05MER}/hectare\) | x |
| s39_cost_establish_forestry | Cost for foresty land expansion | \(USD_{05MER}/hectare\) | x |
| s39_cost_establish_past | Cost for pasture land expansion | \(USD_{05MER}/hectare\) | x |
| s39_cost_establish_urban | Cost for urban land expansion | \(USD_{05MER}/hectare\) | x |
| s39_ignore_calib | Switch for ignoring calibration factors | \(1\) | x |
| s39_reward_shr | Share of cropland expansion cost used as reward for cropland reduction in calibration | \(1\) | x |
| description | |
|---|---|
| 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 |
| t_all(t_ext) | 5-year time periods |
| t(t_all) | Simulated time periods |
| type | GAMS variable attribute used for the output |
| type39 | Cost type |
Florian Humpenöder, Jan Philipp Dietrich, Ulrich Kreidenweis
10_land, 11_costs, 12_interest_rate