Effects of US Maize Ethanol on Global Land Use and Greenhouse Gas Emissions: Estimating Market-Mediated Responses

• Published in: Bioscience Vol. 60; no. 3; pp. 223 - 231
• Main Authors: Hertel, Thomas W, Golub, Alla A, Jones, Andrew D, O'Hare, Michael, Plevin, Richard J, Kammen, Daniel M
• Format: Journal Article
• Language: English
• Published: Circulation, AIBS, 1313 Dolley Madison Blvd., Suite 402, McLean, VA 22101. USA University of California Press 01.03.2010; American Institute of Biological Sciences; Oxford University Press
• Subjects: Agricultural land; Air pollution control; Air quality management; Atmospheric carbon dioxide; Biodiesel fuels; Biofuels; Carbon dioxide; Carbon dioxide emissions; Carbon sequestration; Climate; Climate change; Climate policy; Coarse grains; Control; Corn; DEPARTMENTS; Emissions; Energy security; Environmental aspects; Environmental economics; environmental policy; Estimates; Ethanol; Ethanol fuels; ethanol production; Farmlands; Forest ecosystems; Forest regeneration; Forum; Fossil fuels; Fuels; gas emissions; Global warming; greenhouse gas emissions; Greenhouse gases; Land use; land use change; market-mediated effects; markets; Methods; Pastures; Production capacity; Production increases; United States; Zea mays; United States; California; United States > US; USA; USA, California; market-mediated effects; land-use change; greenhouse gas emissions; biofuels; ethanol
• ISSN: 0006-3568; 1525-3244
• DOI: 10.1525/bio.2010.60.3.8

Releases of greenhouse gases (GHG) from indirect land-use change triggered by crop-based biofuels have taken center stage in the debate over the role of biofuels in climate policy and energy security. This article analyzes these releases for maize ethanol produced in the United States. Factoring market-mediated responses and by-product use into our analysis reduces cropland conversion by 72% from the land used for the ethanol feedstock. Consequently, the associated GHG release estimated in our framework is 800 grams of carbon dioxide per megajoule (MJ); 27 grams per MJ per year, over 30 years of ethanol production, or roughly a quarter of the only other published estimate of releases attributable to changes in indirect land use. Nonetheless, 800 grams are enough to cancel out the benefits that corn ethanol has on global warming, thereby limiting its potential contribution in the context of California's Low Carbon Fuel Standard.