[Terrapreta] Land Clearing and the Biofuel Carbon Debt

[Tom Miles]

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

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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  <http://www.sciencemag.org/cgi/content/abstract/319/5867/1238>
>  |  Full Text  <http://www.sciencemag.org/cgi/content/full/319/5867/1238>
>  |  PDF  <http://www.sciencemag.org/cgi/reprint/319/5867/1238> > 

 

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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