Big Bio-Fuel Industry A Climate Bust!

Science / www.sciencexpress.org / 7 February 2008 /

Use of U.S. Croplands for Biofuels Increases Greenhouse Gases Through
Emissions from Land Use Change
Timothy Searchinger, Ralph Heimlich, R. A. Houghton, Fengxia Dong,
Amani Elobeid, Jacinto Fabiosa, Simla Tokgoz,Dermot Hayes, Tun-Hsiang
Yu

Abstract
Most prior 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. 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.

Land Clearing and the Biofuel Carbon Debt
Joseph Fargione, Jason Hill, David Tilman, Stephen Polasky, Peter Hawthorne

Abstract
Increasing energy use, climate change, and carbon dioxide (CO2)
emissions from fossil fuels make switching to low-carbon fuels a high
priority. Biofuels are a potential low-carbon energy source, but
whether biofuels offer carbon savings depends on how they are
produced. Converting rainforests, peatlands, savannas, or grasslands
to produce food-based biofuels in Brazil, Southeast Asia, and the
United States creates a ‘biofuel carbon debt’ by releasing 17 to 420
times more CO2 than the annual greenhouse gas (GHG) reductions these
biofuels provide by displacing fossil fuels. In contrast, biofuels
made from waste biomass or from biomass grown on abandoned
agricultural lands planted with perennials incur little or no carbon
debt and offer immediate and sustained GHG advantages.

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