Ethanol Could Increase Net Greenhouse Gas Emissions

Ethanol and similar biofuels are known for their efficiency and lower greenhouse gas emissions compared to fossil fuels. However, could these benefits be outweighed by greenhouse-gas effects associated with necessary land-use changes? Thousands of acres of farms in the UNITED STATES were initially used for food production but are now used to harvest crops for ethanol; what effect does this have on the environment? According to Searchinger et al. (2008), diverting harvested crops to ethanol production means that additional land (including forests, grasslands, etc.) has to be converted into farmland to maintain the capacity of crops-for-food production. This results in increased greenhouse gas emissions at rates which may not justify the environmental benefits of ethanol.

"[Most major studies] have found that substituting biofuels for gasoline will reduce greenhouse gases because biofuels sequester carbon through the growth of the feedstock. These analyses have failed to count the carbon emissions that occur as farmers worldwide respond to higher prices and convert forest and grassland to new cropland to replace the grain (or cropland) diverted to biofuels. By using a worldwide agricultural model to estimate emissions from land-use change, we found that corn-based ethanol, instead of producing a 20% savings, nearly doubles greenhouse emissions over 30 years and increases greenhouse gases for 167 years. Biofuels from switchgrass, if grown on U.S. corn lands, increase emissions by 50%. This result raises concerns about large biofuel mandates and highlights the value of using waste products" (Searchinger et al. 2008, 1238).

Searchinger et al.'s report was published in the Science magazine, published by the non-profit American Association for the Advancement of Science. The full research paper is embedded in the Microsoft OneDrive frame below.

● ● ● ● ●  Citing this Work (MLA Formatting)  ● ● ● ● ●
Searchinger, Timothy, Ralph Heimlich, R. A. Houghton, Fengxia Dong, Amani Elobeid, Jacinto Fabiosa, Simla Tokgoz, Dermot Hayes, and Tun-Hsiang Yu. "Use of U.S. Croplands for Biofuels Increases Greenhouse Gases Through Emissions from Land-Use Change." Science 319.5867 (2008): 1238-240. Web.