Mark Bartlett - Environmental Economics

Genetically Modified Crops

The development of genetically modified (GM) crops has led the European Union (EU) to put forward the concept of 'coexistence' to give farmers the freedom to plant both conventional and GM varieties. Should a premium for non-GM varieties emerge in the market, 'contamination' by GM pollen would generate a negative externality to conventional growers. It is therefore important to assess the effect of different policy variables on the magnitude of the externality to identify suitable policies to manage coexistence.

Taking GM herbicide tolerant oilseed rape as an example crop, we develop a model using a Monte Carlo experiment to generate data and then estimate the effect of the number of GM and conventional fields, width of buffer areas and the degree of spatial aggregation (i.e. the policy variables) on the magnitude of the externality at the landscape level.

To represent realistic conditions in agricultural production, we assume that detection of GM material in conventional produce might occur at the field level (no grain mixing occurs) or at the silo level (where grain mixing from different fields in the landscape occurs). In the former case, the magnitude of the externality will depend on the number of conventional fields with average transgenic presence above a certain threshold. In the latter case, the magnitude of the externality will depend on whether the average transgenic presence across all conventional fields exceeds the threshold.

In order to quantify the effect of the relevant policy variables, we compute the marginal effects and the elasticities. Our results show that when relying on marginal effects to assess the impact of the different policy variables, spatial aggregation is far more important when transgenic material is detected at field level, corroborating previous research. However, when elasticity is used, the effectiveness of spatial aggregation in reducing the externality is almost identical whether detection occurs at field level or at silo level. Our results show also that the area planted with GM is the most important policy variable in affecting the externality to conventional growers and that buffer areas on conventional fields are more effective than those on GM fields.

Adapted from the abstract of "Quantifying the effect of buffer zones, crop areas and spatial aggregation on the externalities of genetically modified crops at landscape level"

Complete List of My Publications on GM Crops

On the Regulation of Spatial Externalities: Coexistence between GM and Conventional Crops in the EU and the ‘Newcomer Principle’
M. Graziano Ceddia, Mark Bartlett, Caterina De Lucia, Charles Perrings
Australian Journal of Agricultural & Resource Economics, 55(1), pp126—143, 2011
Quantifying the Effect of Buffer Zones, Crop Areas and Spatial Aggregation on the Externalities of Genetically Modified Crops at Landscape Level
M. Graziano Ceddia, Mark Bartlett, Charles Perrings
Agriculture, Ecosystems & Environment, 129(1—3), pp65—72, 2009
Policies for the Regulation of Coexistence Between GM and Conventional Crops
M. Graziano Ceddia, Mark Bartlett, Charles Perrings
Proc. of 12th Congress of the European Association of Agricultural Economics (EAAE 2008), 2008
Landscape Gene Flow, Coexistence and Threshold Effect: The Case of Genetically Modified Herbicide Tolerant Oilseed Rape (Brassica napus)
M. Graziano Ceddia, Mark Bartlett, Charles Perrings
Ecological Modelling, 205(1–2), pp169–180, 2007
For the full background and description of the model used please see the thesis Policy analysis for the widespread introduction of genetically modified crops : the case of herbicide tolerant oilseed rape" by M. Graziano Ceddia

Computable General Equilibrium Modelling

The interlinked issues of trade and environment in an enlarged Europe are currently subjects of major interest in economics, environmental studies, geography and regional science. This interest is understandable given the substantial consequences of movements of goods and pollution across Europe. Broad differences in trade patterns and environmental policy still exist between European countries (in particular between those of the existing states and those of the new accession countries) meaning that environmental and trade policies can influence the structure of whole economies and emissions levels. This concern has become an increasingly relevant issue, as the optimal design of policy by centralised European institutions has come under greater scrutiny. In particular, the role of national governments in providing public goods appears critical when transboundary externalities are considered and therefore broader inspection of the role of central and local government is necessary.

We consider a theoretical analytic framework based on a two region model of an enlarged Europe to study these issues. The case for uncoordinated and coordinated environmental policies is examined. Specifically, the environmental tax impact on transboundary pollution is assessed on a country's trade, production, and consumption structure.

Through the use of Computable General Equilibrium (CGE) modelling, a quantitative analysis is undertaken of the effects of alterations in environmental and trade taxation. In particular, the focus is on the impact on different economic sectors, transboundary emission levels and welfare effects of environmental policies taken at two levels of government (either at a national level or by central European government) and of liberalization of trade policies in accession countries.

The entry of accession countries into the European Union is found to decrease welfare in these countries while simultaneously increasing it in the existing member states. The results show that accession countries and existing member states would be better off implementing an environmental policy at central level. Environmental policies at a central government level are alone found to be effective in decreasing transboundary emission fluxes compared to the current emission taxation policy.

Adapted from the abstract of "Integrating local and EU environmental policies, trade and transboundary pollution in an enlarged Europe : a computable general equilibrium model"

Complete List of My Publications on CGE Modelling

Environmental Taxation in an Enlarged Europe: A Regional Perspective
Caterina De Lucia, Mark Bartlett
Proc. of the 29th Italian Association of Regional Science Annual Scientific Conference (AISRe 2008) , 2008
For the full background and description of the model used please see the thesis Integrating local and EU environmental policies, trade and transboundary pollution in an enlarged Europe : a computable general equilibrium model by Caterina De Lucia