Variable overview

Drivers

Model driver group	Variable	Used_in	Description
Economic development	GINI coefficient	Human development	Measure of income disparity in a population. If all have the same income, GINI equals 1. The lower the GINI, the wider the gap between the lowest and highest income groups.
Economic development	Timber demand	Forest management	Demand for roundwood and pulpwood per region.
Economic development	Sector value added	Energy supply and demand Energy demand	Value Added for economic sectors: Industry (IVA), Services (SVA) and Agriculture (AVA). These variables are used in IMAGE to indicate economic activity.
Economic development	GDP per capita	Energy supply and demand Agricultural economy Climate policy Emissions Energy demand Human development	Gross Domestic Product per capita, measured as the market value of all goods and services produced in a region in a year, and is used in the IMAGE framework as a generic indicator of economic activity.
Economic development	Labour supply	Agricultural economy	Effective supply of labour input to support economic activities, taking into account the participation rate of age cohorts.
Economic development	GDP per capita - grid	Ecosystem services Nutrients Flood risks	Scaled down GDP per capita from country to grid level, based on population density.
Economic development	Private consumption	Energy supply and demand Energy demand	Private consumption reflects expenditure on private household consumption. It is used in IMAGE as a driver of energy.
Economic development	Capital supply	Agricultural economy	Capital available to replace depreciated stock and expand the stock to support economic growth.
Energy and land resources	Energy resources	Energy supply and demand Energy supply	Volume of energy resource per carrier, region and supply cost class (determines depletion dynamics).
Energy and land resources	Built-up area - grid	Land cover and land use	Urban built-up area per grid cell, excluded from all biophysical modelling in IMAGE, increasing over time as a function of urban population and a country- and scenario-specific urban density curve.
Environmental and other policies	Energy policy	Energy conversion	Policy to achieve energy system objectives, such as energy security and energy access.
Environmental and other policies	Climate target	Climate policy	Climate target, defined in terms of concentration levels, radiative forcing, temperature targets, or cumulative emissions.
Environmental and other policies	Protected area - grid	Land-use allocation Land cover and land use Terrestrial biodiversity Ecosystem services	Map of protected nature areas, limiting use of this area.
Environmental and other policies	Equity principles	Climate policy	General concepts of distributive justice or fairness used in effort sharing approaches. Three key equity principles are: Responsibility (historical contribution to warming); capability (ability to pay for mitigation); and equality (equal emissions allowances per capita).
Environmental and other policies	Domestic climate policy	Climate policy	Planned and/or implemented national climate and energy policies, such as taxes, feed-in tariffs, renewable targets, efficiency standards, that affect projected emission reduction.
Environmental and other policies	Air pollution policy	Energy conversion	Air pollution policies set to reach emission reduction targets, represented in the model in the form of energy carrier and sector specific emission factors.
Environmental and other policies	Biofuel policy	Agricultural economy	Policies to foster the use of biofuels in transport, such as financial incentives and biofuel mandates and obligations.
Environmental and other policies	Taxes and other additional costs	Energy demand	Taxes on energy use, and other additional costs
Environmental and other policies	Adaptation level	Climate policy	Level of adaptation to climate change , defined as the share of climate change damage avoided by adaptation. This level is be calculated by the model to minimise adaptation costs and residual damage, or set by the user.
Lifestyle parameters	Preferences	Energy demand	Non-price factors determining market shares, such as preferences, environmental policies, infrastructure and strategic considerations, used for model calibration.
Lifestyle parameters	Lifestyle parameters	Energy supply and demand Energy demand	Lifestyle parameters influence the relationship between economic activities and demand for energy.
Population projections	Population - grid	Land-use allocation Nutrients Human development Flood risks	Number of people per gridcell (using downscaling).
Population projections	Population	Energy supply and demand Agricultural economy Climate policy Energy demand	Number of people per region.
Population projections	Urban population fraction	Human development	Urban/rural split of population.
Technological change in agriculture and forestry	Increase in irrigated area - grid	Land-use allocation	Increase in irrigated area, often based on external projections (e.g., FAO).
Technological change in agriculture and forestry	Harvest efficiency	Forest management	Fraction of harvested wood used as product, the remainder being left as residues. Specified per biomass pool and forestry management type.
Technological change in agriculture and forestry	Forest plantation demand	Forest management	Demand for forest plantation area.
Technological change in agriculture and forestry	Production system mix	Livestock systems Nutrients	Livestock production is distributed over two systems for dairy and beef production (intensive: mixed and industrial; extensive: pastoral grazing), and to three systems for pigs (backyard, intermediate, intensive) and poultry (backyard, boilers, laying hens) with specific intensities, rations and feed conversion ratios.
Technological change in agriculture and forestry	Irrigation project efficiency		Ratio of quantity of irrigation water required by the crop (based on soil moisture deficits) to the quantity withdrawn from rivers, lakes, reservoirs or other sources. This parameter is given at country level.
Technological change in agriculture and forestry	Irrigation conveyance efficiency		Ratio of water supplied to the irrigated field to the quantity withdrawn from the water source, determining the quantity of water lost during transport. This parameter is defined at country level.
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