New
report finds biofuels produce more greenhouse gas than fossil fuels do
By Craig Weatherby
Were
really not trying to make food-based fuels look bad. Its just that new reports
keep questioning the economic and environmental credibility of growing food crops
like corn, soy, and sugarcane to make fuel.
Recently,
official Swiss and British studies concluded that fuels made from corn, soy, or
sugarcane constitute energy-inefficient alternatives that worsen both global warming
and environmental destruction on the ground.
Those
reports were largely ignored by the American media, but thats changed with
the release last week of two studies that confirmed their critical conclusions.
The US media
paid more attention to the new studies, perhaps because both were published in
the prestigious journal Science by researchers from American institutions: Princeton
University, Woods Hole Research Center, Iowa State University the University of
Minnesota and the Nature Conservancy.
In
short, the US-based new studies find that making biofuels from most food crops
cause more greenhouse gas emissions than conventional fuels, if you include the
processes required to produce ethanol from crops.
It
had been assumed that the carbon released when land was cleared to plant crops
for biofuel burned was balanced by the carbon absorbed as those crops grew.
But the process
of turning plants into fuels involves emissions from refining and transport, among
other things.
And
one of the studies concluded that clearance of grassland releases 93 times the
amount of greenhouse gas that would be saved by the fuel made annually on that
land (Fargione J et al 2008).
Heres
how the authors summarized their papers conclusions:
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. (Searchinger T et al. 2008)
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 T et al. 2008)
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. (Fargione J et al 2008)
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. (Fargione J et al 2008)
By
... biomass grown on abandoned agricultural lands planted with perennials
... the authors mean fibrous weeds like switchgrass. Likewise, they find
no fault with using waste vegetable oil as bio-diesel.
The
team led by Princetons Timothy Searchinger noted one possible exception
sugar cane grown in Brazil which takes relatively little energy
to grow and is most easily refined into fuel.
Both
groups recommend shifting the focus to developing biofuels from agricultural and
logging waste products, as is happening in the promising Australian project we
covered last week (see Bio-Fuel
Breakthrough Claimed by Australians)
Sources
* Searchinger T, Heimlich R, Houghton RA, Dong F, Elobeid A, Fabiosa J, Tokgoz
S, Hayes D, Yu T. Use of U.S. Croplands for Biofuels Increases Greenhouse Gases
Through Emissions from Land Use Change. Published online February 7 2008; 10.1126/science.1151861
(Science Express Reports)
* Fargione J, Hill J, Tilman D, Polasky S,
Hawthorne P. Land Clearing and the Biofuel Carbon Debt. Published online February
7 2008; 10.1126/science.1152747 (Science Express Reports)
* Princeton
University. New study by STEP researcher Searchinger: biofuels may increase greenhouse
gas emissions. Accessed online February 10, 2008 at http://wws.princeton.edu/coverstories/searchinger_article/index.xml
* German Marshall Fund of the United States. Converting forest and grassland
to cropland adds previously unforeseen greenhouse gas emissions to the cost of
biofuels, new study says. Accessed online February 10, 2008 at http://www.gmfus.org/press/article.cfm?id=132&parent_type=R.
Note
from Chet: Here at Health & Beyond Online,
we wouldn't think of eating any salmon other than the wild Alaskan salmon we get
from Randy Hartnell at Vital Choice Seafood. Click
here to order the best salmon I've ever tasted, and
be sure to mention Chet Day as referring you.
Click
Here to
share this page with your friends, website visitors, ezine readers, social followers
and other online contacts.
Disclaimer:
Throughout this website, statements are made pertaining to the properties and/or
functions of food and/or nutritional products. These statements have not been
evaluated by the Food and Drug Administration and these materials and products
are not intended to diagnose, treat, cure or prevent any disease.