| Subject: So you're in favor of Carbon Offsets used by Al Gore and the Hollywood glitteriara |
Author:
Ex-bushy
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Date Posted: 09:35:29 08/17/07 Fri
In reply to:
larry
's message, "Forget biofuels - burn oil and plant forests instead" on 05:55:47 08/17/07 Fri
Some people can walk and chew gum and the same time, even while we run out of oil.
>It sounds counterintuitive, but burning oil and
>planting forests to compensate is more environmentally
>friendly than burning biofuel. So say scientists who
>have calculated the difference in net emissions
>between using land to produce biofuel and the
>alternative: fuelling cars with gasoline and
>replanting forests on the land instead.
>
>They recommend governments steer away from biofuel and
>focus on reforestation and maximising the efficiency
>of fossil fuels instead.
>
>The reason is that producing biofuel is not a "green
>process". It requires tractors and fertilisers and
>land, all of which means burning fossil fuels to make
>"green" fuel. In the case of bioethanol produced from
>corn – an alternative to oil – "it's essentially a
>zero-sums game," says Ghislaine Kieffer, programme
>manager for Latin America at the International Energy
>Agency in Paris, France (see Complete carbon footprint
>of biofuel - or is it?).
>
>What is more, environmentalists have expressed
>concerns that the growing political backing that
>biofuel is enjoying will mean forests will be chopped
>down to make room for biofuel crops such as maize and
>sugarcane. "When you do this, you immediately release
>between 100 and 200 tonnes of carbon [per hectare],"
>says Renton Righelato of the World Land Trust, UK, a
>conservation agency that seeks to preserve rainforests.
>
>Century-long wait
>Righelato and Dominick Spracklen of the University of
>Leeds, UK, calculated how long it would take to
>compensate for those initial emissions by burning
>biofuel instead of gasoline. The answer is between 50
>and 100 years. "We cannot afford that, in terms of
>climate change," says Righelato.
>
>The researchers also compared how much carbon would be
>stored by replanting forests with how much is saved by
>burning biofuel grown on the land instead of gasoline.
>
>They found that reforestation would sequester between
>two and nine times as much carbon over 30 years than
>would be saved by burning biofuels instead of gasoline
>(see bar chart, right). "You get far more carbon
>sequestered by planting forests than you avoid
>emissions by producing biofuels on the same land,"
>says Righelato.
>
>He and Spracklen conclude that if the point of
>biofuels policies is to limit global warming, "policy
>makers may be better advised in the short term to
>focus on increasing the efficiency of fossil fuel use,
>to conserve existing forests and savannahs, and to
>restore natural forest and grassland habitats on
>cropland that is not needed for food."
>
>They do admit, however, that biofuels made from woody
>materials such as prairie grasses may have an
>advantage over reforestation – although it is
>difficult to say for now as such fuels are still in
>development (see Humble grasses may be the best source
>of biofuel).
>
>Forests at high latitudes have been found to sequester
>less carbon than tropical forests (see Some forests
>may speed global warming). But Righelato says this
>does not affect his calculations as biofuel crops are
>not, by and large, grown in these areas.
>
>
>href="http://environment.newscientist.com/article/dn124
>96-forget-biofuels--burn-oil-and-plant-forests-instead.
>html">http://environment.newscientist.com/article/dn124
>96-forget-biofuels--burn-oil-and-plant-forests-instead.
>html
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