Environmental-Economic Modelling


The OECD has been using economic models and quantitative assessments since the late 1980s to inform policy makers of the costs, benefits and potential tradeoffs of environmental policies and climate change mitigation scenarios. The main environmental-economic modelling work of the OECD rests upon the in-house models ENV-Linkages, a dynamic general equilibrium model and ENV-Growth, a macroeconomic growth model based on a conditional convergence framework. This modelling work is aimed to assist governments in identifying least-cost policies or policy mixes to reduce greenhouse gas (GHG) emissions, and assesses the cost and impacts of environmental policies and of possible post-2012 international frameworks, among other applications.

OECD work on modelling economy-environment interactions


Outlooks and CIRCLE | Climate change mitigation | Energy | Distributional impacts 

Modelling tools

ENV-Linkages model

The ENV-Linkages model is a recursive dynamic neo-classical general equilibrium model (GE). It is a global economic model built primarily on a database of national economies (GTAP V8 Database). In its current form, the model represents the world economy in 25 countries/regions, each with 35 economic sectors.

The baseline projection as used for the Environmental Outlook to 2050 describes an internally consistent set of trends of all economic and environmental variables of the model. The baseline assumes no new policies for the environmental issues addressed and thus provides a benchmark against which policy scenarios can be assessed.

Summary flyer (pdf)

ENV-Growth model

The ENV-Growth model is a two-sector model that aims at projecting GDP and per capita income levels for all major economies in the world (currently more than 185 countries). The model is based on conditional convergence between countries in the main drivers of economic growth: labour, human capital, physical capital, natural resources and total factor productivity.

ENV-Growth is used in the construction of baseline projections for ENV-Linkages.  Furthermore, ENV-Growth is applied to construct macroeconomic projections for the so-called Shared Socioeconomic Pathways (SSPs) for climate change. Preliminary results of these projections are available at https://secure.iiasa.ac.at/web-apps/ene/SspDb

  Summary Flyer (pdf)

OECD Environmental Outlook to 2050 Baseline projection (OECD, 2012)


OECD Environmental Outlook to 2050 Baseline projection (OECD, 2012)


  • An overview of the OECD ENV-Linkages Model (2014) presents a summary description of the OECD ENV-Linkages General Equilibrium model.  The paper provides a brief description to the structure of the ENV-Linkages model and of its main equations, and describes the calibration method.

  • An Economic Projection to 2050: The OECD "ENV-Linkages" Model Baseline (2011) describes possible future developments and is not a prediction of the future.  Rather, it provides an internally consistent set of trends of all economic and environmental variables of the model.  The baseline assumes no new policies for the environmental issues addressed and thus provides a benchmark against which policy scenarios can be assessed.
  • A full description of the ENV-Growth model is forthcoming.


Environmental Outlooks and the Costs of Inaction and Resource Scarcity: Consequences for Long-term Economic Growth (CIRCLE)

  • The OECD has produced a series of Environmental Outlooks to help policy makers understand the most urgent environmental challenges as well as the economic and environmental implications of the policies that could be used to address these challenges. The CIRCLE project takes the next step and aims at looking at the feedbacks from environmental challenges on economic growth. The Environmental Outlooks and CIRCLE assess a range of important environmental challenges, including climate change, health and environment, loss of biodiversity and ecosystems and water-economy linkages.
  • The most recent Outlook, the OECD Environmental Outlook to 2050: The Consequences of Inaction provides model-based future-oriented analyses of economic and environmental trends in the coming decades. The economic and environmental projections are made possible by combining the ENV-Linkages model at the OECD Environment Directorate with the comprehensive environmental modelling framework of the IMAGE (Integrated Model to Assess the Global Environment) suite of models run by the Netherlands Environmental Assessment Agency (PBL).

 More about the OECD Environmental Outlook to 2050: The Consequences of Inaction (2012)

Costs of Inaction and Resource Scarcity: Consequences for Long-term Economic Growth

Climate change mitigation

The ENV-Linkages model, with its general equilibrium structure, is a powerful tool to analyse the impacts of climate change mitigation policies.  Analytical work based on the ENV-Linkages model development spans over a wide range of issues dealing with the interlinkages between environment and the economy: costs and effectiveness of carbon markets, linking of carbon markets, climate change mitigation and employment, climate change mitigation policies and energy policies such as the removal of fossil fuel subsidies.

Highlights of Model Results:

Source: ENV-Linkages Model (2011)

Carbon Markets

 More about OECD Work on Carbon Markets


  Climate change mitigation policy and employment

The implementation of a green growth agenda may translate into deep changes in the labour market that extend far beyond the creation of what are often labelled as “green jobs”. While there are a number of opportunities associated with green growth, there are also costs associated with the transition.  This topic is analysed in the working paper Employment Impacts of Climate Change Mitigation Policies in OECD: A General-Equilibrium Perspective (2011).


  Policies for cost-effective mitigation

Against the background of a projected doubling of world greenhouse gas emissions by mid-century, the book The Economics of Climate Change Mitigation: Policies and Options for Global Action Beyond 2012 (2009) explores through quantitative analysis feasible ways to abate them at least cost.

More about Economics of Climate Change Mitigation



The ENV-Linkages model has traditionally been linked to the IEA World Energy Model (WEM) in order to provide economic impacts of the IEA World Energy Outlooks scenarios.  Since 2011, a more sophisticated methodology is used to link these models.

More on the Macroeconomic of energy efficiency using the OECD ENV-Linkages model.


  • The paper Economic Impacts of the IEA World Efficient Scenario (2014) provides a background report about macroeconomic impacts of the "World Efficient Scenario" presented in the WEO (2012) and highlights the economic and environmental benefits of investing in energy efficiency.

 More about the OECD-IEA work on Fossil Fuel Subsidies and Other Supports


Distributional impacts of environmental policies

The costs of environmental policies may significantly differ across households, though such policies can give opportunities to reduce poverty and inequalities if combined with appropriate redistribution of the revenues they raise.  In order to investigate the impact of environmental policies on poverty and inequalities, the ENV-Linkages model, which in its core specification relies on a single regional representative household, is extended to include - for some regions - an explicit representation of various households groups, differentiated by preferences and incomes sources.  This version of the model is used to provide an assessment of the distributional impacts of policy packages where energy subsidy or green tax reforms are implemented.

  • "Modelling of distribution impacts of energy subsidy reforms: An illustration with Indonesia", Environment Working Paper No. 86, provides, in the case of Indonesia, an assessment of the economic, environmental and distributional impacts of fossil fuels consumptions subsidy reforms. The study is based on the context that pertained until mid-2014, when international oil prices where high and before the recent phase out of Gasoline and Disesel subsidies by the Indonesian authorities. This work is based on a version of ENV-Linkages that includes over 10 000 Indonesian household groups.

Main findings - The simulated GDP impacts of the fossil fuel subsidy phase out is positive, ranging from 0.4% to 0.7% in 2020 with respect to a baseline with no phase out. The GHG emissions reductions are between 8% and 10%. The distributional effects depend on the type of redistribution schemes used. Cash transfers make the reform progressive. However, when redistribution is based on labour income, it become regressive because it targets formal sector workers only, who are in general better off that the rest of the population. The food subsidies make the reform slightly progressive, but create inefficiencies which partly offset the beneficial effect of the subsidy reform on GDP. 



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