Does certified organic farming reduce greenhouse gas emissions from agricultural production? Comment on the McGee study
- 541 Downloads
A recent study by McGee (Agriculture and Human Values, 32, 255–263, 2015) from the University of Oregon has led to discussions in international media and on the web. This study addresses an interesting question and applies advanced statistics for its analysis. However, we identify several methodological flaws that invalidate the results. First, McGee tests a hypothesis that does not correspond to his main question and which does not allow McGee to derive the conclusions that are drawn in his paper and reported in the media coverage. Second, the data used are not adequate for the analysis because: i) the dependent variable does not reflect the greenhouse gas emissions characteristics of organic agriculture (e.g. different emission factors in organic and conventional agriculture or avoidance of emissions from fertilizer production), ii) the explanatory variables neglect the livestock sector, and iii) trade aspects are missing. Third, McGee fails to discuss his findings in the light of quite a substantial body of experimental, bio-physical research from the US and elsewhere.
KeywordsOrganic farming Greenhouse gas emissions Conventionalization
The authors would like to thank the Mercator Foundation Switzerland for funding earlier and current work on this subject through the projects “Carbon Credits for Sustainable Land Use Systems (CaLas)” and “The Potential of Sustainable Land-Use Systems to Promote Adaptation to Climate Change.”
- Beck, N. 2008. Time-series cross-section methods. In The Oxford Handbook of Political Methodology, ed. J. Box-Steffensmeir, H. Brady, and D. Collier, 475–493. London: Oxford University Press.Google Scholar
- Deaton, A., and J. Muellbauer. 1980. An almost ideal demand system. The American Economic Review 70(3): 312–326.Google Scholar
- MailOnline. 2015. Is organic farming making climate change worse? Demand for ‘sustainable’ food has increased greenhouse gas emissions, by Richard Grey, Wednesday 15 July. http://www.dailymail.co.uk/sciencetech/article-3162733/Is-organic-farming-making-climate-change-worse-Demand-sustainable-food-increased-greenhouse-gas-emissions.html. Accessed 30 July 2015.
- The Guardian. 2015. Organic farms don’t have the tiny carbon footprint they like to tout. But they could by Julius McGee, Tuesday 21 July. http://www.theguardian.com/commentisfree/2015/jul/21/organic-farms-carbon-footprint-climate-change. Accessed 30 July 2015.
- Tilman, D., and M. Clark. 2014. Global diets link environmental sustainability and human health. Nature 515:518–522. doi: 10.1038/nature13959 http://www.nature.com/nature/journal/v515/n7528/abs/nature13959.html#supplementary-information.
- UoO. 2015. Study suggests organic farming needs direction to be sustainable, University of Oregon, Sunday, 12 July. https://around.uoregon.edu/content/study-suggests-organic-farming-needs-direction-be-sustainable. Accessed 30 July 2015.
- Zhang, W.-F., Z. Dou, P. He, X.T. Ju, D. Powlson, D. Chadwick, D. Norse, Y.-L. Lu, Y. Zhang, L. Wu, X.-P. Chen, K.G. Cassman, and F.-S. Zhang. 2013. New technologies reduce greenhouse gas emissions from nitrogenous fertilizer in China. Proceedings of the National Academy of Sciences of the United States of America 110: 8375–8380. doi: 10.1073/pnas.1210447110.CrossRefGoogle Scholar