[Terrapreta] Land Clearing and the Biofuel Carbon Debt

[compostable]

Here's a followup letter to Science from Argonne National Lab (the 2nd article below used an analytical model developed by ANL)
 http://www.transportation.anl.gov/media_center/news_stories/20080214_response.html

----- Original Message ----- 
  From: Tom Miles 
  To: 'Terra Preta' 
  Sent: Monday, March 10, 2008 1:37 AM
  Subject: [Terrapreta] Land Clearing and the Biofuel Carbon Debt


  A couple of interesting articles in Science Magazine

   

  See: http://www.sciencemag.org/cgi/content/abstract/319/5867/1235

  Shows the below ground and above gorund carbon loss from converting land to biofuels. Considers various land use ecosystems.  

   

  And

  http://www.sciencemag.org/cgi/content/abstract/319/5867/1238

  Compares land use effects and net GHG from various biofuels. 

         

        Originally published in Science Express on 7 February 2008


        Science 29 February 2008:
        Vol. 319. no. 5867, pp. 1235 - 1238
        DOI: 10.1126/science.1152747
       Prev | Table of Contents | Next 
       

  Reports
  Land Clearing and the Biofuel Carbon Debt
  Joseph Fargione,1 Jason Hill,2,3 David Tilman,2* Stephen Polasky,2,3 Peter Hawthorne2 

  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 crop-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 that these biofuels would provide by displacing fossil fuels. In contrast, biofuels made from waste biomass or from biomass grown on degraded and abandoned agricultural lands planted with perennials incur little or no carbon debt and can offer immediate and sustained GHG advantages. 

  1 The Nature Conservancy, 1101 West River Parkway, Suite 200, Minneapolis, MN 55415, USA.
  2 Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN 55108, USA.
  3 Department of Applied Economics, University of Minnesota, St. Paul, MN 55108, USA. 

  Use of U.S. Croplands for Biofuels Increases Greenhouse Gases Through Emissions from Land-Use Change.

  T. Searchinger, R. Heimlich, R. A. Houghton, F. Dong, A. Elobeid, J. Fabiosa, S. Tokgoz, D. Hayes, and T.-H. Yu (2008)
  Science 319, 1238-1240 
   |  Abstract »  |  Full Text »  |  PDF » 

   

  Use of U.S. Croplands for Biofuels Increases Greenhouse Gases Through Emissions from Land-Use Change

  Timothy Searchinger,1* Ralph Heimlich,2 R. A. Houghton,3 Fengxia Dong,4 Amani Elobeid,4 Jacinto Fabiosa,4 Simla Tokgoz,4 Dermot Hayes,4 Tun-Hsiang Yu4 

  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. 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. 

  1 Woodrow Wilson School, Princeton University, Princeton, NJ 08544, USA. German Marshall Fund of the United States, Washington, DC 20009, USA. Georgetown Environmental Law and Policy Institute, Washington, DC 20001, USA.
  2 Agricultural Conservation Economics, Laurel, MD 20723, USA.
  3 Woods Hole Research Center, Falmouth, MA 02540-1644, USA.
  4 Center for Agricultural and Rural Development, Iowa State University, Ames, IA 50011, USA. 

   



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