http://www.nzherald.co.nz/section/2/story.cfm?c_id=2&objectid=10492276
5:00AM Thursday February 14, 2008
Converting land to biofuel crops releases vast amounts of carbon
dioxide. Photo / Reuters
Converting land to biofuel crops releases vast amounts of carbon
dioxide. Photo / Reuters
Climate Change
Growing crops to make biofuels results in vast amounts of carbon dioxide
being released into the atmosphere and does nothing to stop climate
change or global warming, according to the first thorough scientific
audit of a biofuel's carbon budget.
Scientists have produced damning evidence to suggest that biofuels could
be one of the biggest environmental cons, because they actually make
global warming worse by adding to the man-made emissions of carbon
dioxide that they are supposed to curb.
Two separate studies published in the journal Science show that a range
of biofuel crops now being grown to produce alternatives to oil-based
fossil fuels release far more carbon dioxide into the air than can be
absorbed by the growing plants.
The scientists found that in the case of some crops it would take
several centuries of growing them to pay off the "carbon debt" caused by
their initial cultivation. These environmental costs do not take into
account any extra destruction to the environment, for instance the loss
of biodiversity caused by clearing tracts of rainforest.
"All the biofuels we use now cause habitat destruction, either directly
or indirectly," said Joe Fargione of the US Nature Conservancy, who was
the lead scientist in one of the studies.
"Global agriculture is already producing food for six billion people.
Producing food-based biofuel, too, will require that still more land be
converted to agriculture."
The scientists carried out the sort of analysis that has been missing in
the rush to grow biofuels, encouraged by policies in the US and Europe
where proponents have been keen to extol biofuels' virtues as a green
alternative to the fossil fuels used for transport.
Both studies looked at how much carbon dioxide is released when a piece
of land is converted into a biofuel crop.
They found that when peat lands in Indonesia are converted into palm-oil
plantations, for instance, it would take 423 years to pay off the carbon
debt. The next worse case was when forested land in the Amazon is cut
down to convert into soybean fields. The scientists found that it would
take 319 years of making biodiesel from the soybeans to pay off the
carbon debt caused by chopping down the trees in the first place.
Such conversions of land to grow corn, maize and sugarcane for
biodiesel, or palm oil and soybean for bioethanol, release between 17
and 420 times more carbon than the annual savings from replacing fossil
fuels, the scientists calculated.
"This research examines the conversion of land for biofuels and asks the
question, 'Is it worth it?' Does the carbon you lose by converting
forests, grasslands and peat lands outweigh the carbon you 'save' by
using biofuels instead of fossil fuels?" Dr Fargione said.
And surprisingly the answer is 'no'. These natural areas store a lot of
carbon, so converting them to croplands results in tonnes of carbon
emitted into the atmosphere."
The demand for biofuels is destroying the environment in other ways.
American farmers, for instance, used to rotate between soybean and corn
crops, but the demand for biofuel has meant that they are now growing
corn only.
As a result, Brazilian farmers are cutting down forests to grow soybean
to meet the shortfall in production.
"In finding solutions to climate change, we must ensure that the cure is
not worse than the disease," said Jimmie Powell, a member of the
scientific team at the Nature Conservancy.
"We cannot afford to ignore the consequences of converting land for
biofuels. Doing so means we might unintentionally promote fuel
alternatives that are worse than the fossil fuels they are designed to
replace. These findings should be incorporated into carbon emission
policy going forward."
The European Union is already having second thoughts about its policy
aimed at stimulating the production of biofuel. Stavros Dimas, the EU
environment commissioner, admitted last month that the EU did not
foresee the scale of the environmental problems raised by Europe's
target of deriving 10 per cent of its transport fuel from plant material.
Professor John Pickett, chair of the recent study on biofuels
commissioned by the Royal Society, said that although biofuels may play
an important role in cutting greenhouse gases from transport, it is
important to remember that one biofuel is not the same as another.
"The greenhouse gas savings that a biofuel can provide are dependent on
how crops are grown and converted and how the fuel is used," Professor
Pickett said.
"Given that biofuels are already entering global markets, it will be
vital to apply carbon certification and sustainability criteria to the
assessment of biofuels to promote those that are good for people and the
environment.
"This must happen at an international level so that we do not just
transfer any potentially negative effects of these fuels from one place
to another."
Professor Stephen Polasky of the University of Minnesota, an author of
one of the studies published in Science, said the incentives currently
employed to encourage farmers to grow crops for biofuels do not take
into account the carbon budget of the crop.
"We don't have the proper incentives in place because landowners are
rewarded for producing palm oil and other products but not rewarded for
carbon management," Professor Polasky said.
"This creates incentives for excessive land clearing and can result in
large increases in carbon emissions."
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Check for earlier Pacific Biofuel posts: http://pacbiofuel.blogspot.com/
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