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 | \(10^6 USD_{17MER}/yr\) |
This realization accounts for land conversion costs of cropland, pasture, forestry and urban land. Costs for expansion of forestry and urban land are global and static over time. For cropland and pasture, a regional and time-dependent calibration factor is applied on global costs for land expansion, complemented by a reward for cropland/pasture reduction in selected regions, for a better match of regional cropland and pasture area in 2015 with historic data. The calibration factors for costs of cropland and pasture expansion are 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 |
| f39_calib_past (t_all, i, type39) |
Calibration factor for costs of pasture expansion | \(1\) | x |
| i39_calib (t, i, type39) |
Calibration factor for costs of cropland expansion and rewards for cropland reduction | \(1\) | x |
| i39_calib_past (t, i, type39) |
Calibration factor for costs of pasture expansion and rewards for pasture reduction | \(1\) | x |
| i39_cost_establish (t, i, land) |
Land expansion costs | \(USD_{17MER}/hectare\) | x |
| i39_reward_reduction (t, i, land) |
Reward for land reduction | \(USD_{17MER}/hectare\) | x |
| q39_cost_landcon (j, land) |
Calculation of cellular landconversion costs | \(10^6 USD_{17MER}/yr\) | x |
| s39_cost_establish_crop | Cost for cropland expansion before calibration | \(USD_{17MER}/hectare\) | x |
| s39_cost_establish_forestry | Cost for forestry land expansion | \(USD_{17MER}/hectare\) | x |
| s39_cost_establish_past | Cost for pasture land expansion before calibration | \(USD_{17MER}/hectare\) | x |
| s39_cost_establish_urban | Cost for urban land expansion | \(USD_{17MER}/hectare\) | x |
| s39_ignore_calib | Switch for ignoring cropland calibration factors | \(1\) | x |
| s39_ignore_calib_past | Switch for ignoring pasture calibration factors | \(1\) | x |
| s39_reward_crop_reduction | Reward for cropland reduction before calibration | \(USD_{17MER}/hectare\) | x |
| s39_reward_past_reduction | Reward for pasture reduction before calibration | \(USD_{17MER}/hectare\) | x |
| description | |
|---|---|
| cell(i, j) | number of LPJ cells per region i |
| ct(t) | Current time period |
| factors | factors included in factor requirements |
| 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(t_all) | Simulated time periods |
| t_all(t_ext) | 5-year 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