Search results

This survey presents the recent and rapidly expanding literature, which analyses the economic impacts of the COVID-19 pandemic, by means of Computable General Equilibrium (CGE) modelling. It does so not only by contrasting and assessing the different methodological approaches, and the key findings of the simulation exercises, but also by putting the various contributions in a historical perspective. This is necessary because each CGE-based study should be evaluated while keeping in mind when it was realised, since questions, priorities, expectations have been constantly changing during the spreading of the pandemic.

John Gilbert is a professor of economics in the Department of Economics and Finance, Jon M. Huntsman School of Business, at Utah State University. He has worked as a consultant for the World Bank, UNESCAP, ADBI, and the Peterson Institute for International Economics, and has published extensively in the area of trade theory and policy, and on the computable general equilibrium analysis of regional trading arrangements.

This chapter presents a global computable general equilibrium model with firm heterogeneity based on the Melitz (2003) framework and examines the relative importance of the intensive and extensive margins in the trade expansion following trade liberalization. Using a set of plausible parameters values suggested by empirical studies and calibrating the model to the recent Global Trade Analysis Project (GTAP) global database, our illustrative simulations indicate that the extensive margin accounts for around one-third of the trade growth induced by a reduction in tariffs or variable trade costs. In the case of reducing fixed trade costs, the extensive margin contributes almost 200 percent of the trade expansion, with the intensive margin contributing negatively to trade growth.

Purpose – The chapter examines the international welfare effects of biotech crop adoption, based on a transversal literature review and a case study of the introduction of genetically modified (GM) food crops in Bangladesh, India, Indonesia, and the Philippines.

Methodology/approach – The analysis is based on (a) a review of lessons from the applied economic literature and (b) simulations using an improved multimarket, multicountry, computable general equilibrium (CGE) model, calibrated with productivity hypotheses formulated with local scientists in the four Asian countries.

Findings – Results from the analysis show that, in the absence of trade-related regulations, GM crop adoption generates economic gains for adopting countries and importing non-adopters, that domestic regulations at adopters and especially non-adopters can reduce these gains, and that import regulations in other countries can also affect gains for exporting adopters. The case study illustrates these conclusions, but it also shows that net importers will mostly benefit from adoption in their terms of trade, and that segregation of non-GM crops for export markets can be beneficial if it is not too costly.

Research limitations/implications – The use of a CGE model allows for accounting for cross-sectoral effects, and for regulations affecting bilateral trade flows, but it also has a number of limitations. The model used here, like the ones used in the other papers in the literature, is static, based on an aggregated representation of the global economy (GTAP database), and assumes perfect competition. This means that the absolute results of each scenario may not perfectly represent the actual welfare effects engendered by the adoption of biotech crops. Still, what matters here is the comparison of the relative welfare effects across countries and scenarios. The simulations are also done ex-ante, so, even if the model here was calibrated with country-based data, the results do depend on hypothetical assumptions about the performance of the selected technologies.

Originality/value of the paper – The chapter aims to illustrate the welfare effects generated by GM crops for adopters, non-adopters, in a segmented and regulated international market. Unlike other papers, the review section provides key transversal lessons from the literature, accounting for results from both partial equilibrium and CGE model studies. The empirical application focuses on four populous Asian countries that have been largely left out of the literature. The model used in the simulation presents a number of improvement from the CGE literature on GM crops, including partial adoption, factor-biased productivity shock in each adopting country, GM labeling regulations modeled as trade filters, and the inclusion of costly non-GM segregation as observed in the international market.