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讲座预告:Colin Thirtle:An Econometric Approach to Ozone Pollution


时间:2018年4月12日(周四) 11:00



The Impact of Tropospheric Ozone Pollution on Trial Plot Winter Wheat Yields on Great Britain - An Econometric Approach


Colin Thirtle

Colin Thirtle is Emeritus Professor of Agricultural Development Economics in the Centre for Environmental Policy, Imperial College London. He also has appointments as Extraordinary Professor at the University of Pretoria and the University of Stellenbosch. 

His undergraduate degree is from the London School of Economics and he has post-graduate degrees from Southern Illinois University and Columbia University, where he taught before moving on to San Francisco and Manchester.  He has published several books including The Role of Supply and Demand in the Generation and Diffusion of Technical Change (with Vernon Ruttan), Productivity, Efficiency and Land Markets in South African Agriculture (with Johan van Zyl), South African Agriculture at the Crossroads: An Empirical Analysis of Efficiency, Technology and Productivity (with Johan van Zyl and Nick Vink) and over one hundred journal articles on agricultural R&D, technology and productivity.

Research Interests:  The allocation of resources in R&D systems and the generation of technologies; rates of return to R&D expenditures; the efficiency and productivity effects of innovations; induced innovation and the diffusion of technology; environmental effects; GM crops; biodiversity.


Low level ozone pollution is thought to be a cause of yield loss in cereal crops, especially in rapidly industrialising countries such as China and India.  Numerous scientific experiments have demonstrated reductions in the yields of cereal crops due to tropospheric O3, with losses of up to 25%. However, the only British econometric study on O3 impacts on winter wheat yields, found that a 10% increase in AOT40 would decrease yields by only 0.23%.  An attempt is made here to reconcile these observations by developing AOT40 maps for Great Britain and matching levels with a large number of standardised trial plot wheat yields from many sites over a 13 year period. Panel estimates (repeated measures on the same plots with time) show a 0.54% decrease in yields and it is hypothesised that plant breeders may have inadvertently selected for O3 tolerance in wheat. Some support for this is provided by fumigations of cultivars of differing introduction dates. A case is made for the use of econometric as well as experimental studies in prediction of air pollution induced crop loss.