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Biofuel breakdown

By Katherine Bagley Biofuel breakdown The paper: T. Searchinger et al., “Use of U.S. croplands for biofuels increases greenhouse gases through emissions from land-use change,” Science, 319:1238–40, 2008. (Cited in 204 papers) The finding: Fossil fuel energy systems are one-sided: emitting carbon, but not sequestering it. Crops, on the other hand, help sequester carbon as they grow, a fact that led most prior research to conclude

By | March 1, 2010

Biofuel breakdown

The paper:
T. Searchinger et al., “Use of U.S. croplands for biofuels increases greenhouse gases through emissions from land-use change,” Science, 319:1238–40, 2008. (Cited in 204 papers)

The finding:
Fossil fuel energy systems are one-sided: emitting carbon, but not sequestering it. Crops, on the other hand, help sequester carbon as they grow, a fact that led most prior research to conclude that replacing gasoline with biofuels would help reduce greenhouse gas emissions. But as demand for biofuels increases, farmers would need to convert maturing forest and grassland to cropland, a lower-quality carbon sequester. Using worldwide agricultural models and land-conversion rates, Timothy Searchinger from Princeton University and colleagues found that using corn-based ethanol would actually double greenhouse gas emissions over 30 years. “People saw land use change as an unrelated component to emissions estimates,” says Searchinger. “But not including it was a basic error” in analyzing the benefits of biofuels.

The backlash:
“The biofuels industry was livid,” says Jason Hill, a bioenergy researcher at the University of Minnesota. “And a tremendous amount of debate broke out within the industry, policymakers, and the general public over what our energy future should look like.”

The backdrop:
At the time the paper was published, former President George W. Bush had just signed the Energy Independence and Security Act into law. A large portion of the bill required biofuels to achieve lower net emissions than petroleum.

The impact:
As a result of this paper, most biofuel assessments today incorporate land use change into their emission calculations.

Land subject to conversion with corn-based ethanol use:
Worldwide: 10.8 million hectares
United States: 2.2 million hectares
Brazil: 2.8 million hectares
China: 2.3 million hectares

Comments

Avatar of: ERIC J MURPHY

ERIC J MURPHY

Posts: 18

March 16, 2010

First and foremost, in the plain states, farmers have taken their worse land out of production and put it into government programs such as CRP. This land is not really able to support the growth of high quality crops like soybeans or corn. Hence, the idea that it will be put into production for low yields of corn are not overly savvy from an agronomic point of view.\n\nSecond, the increased number of acres devoted to corn reduces the number of acres devoted to other crops including pulse crops. In North Dakota, corn acres are up while acres devoted to other cropping choices, e.g. flax, barley, have dropped. Farmers make cropping choices based upon price, which is driven by demand. Thus, from a food policy point of view, things become out of balance producing shortages in particular crops that ultimately impact the consumer. The hope is that there is self-correction in production as the prices of these other, forgotten crops rise, again driving farmers to make new cropping choices.\n\nHowever, the need for alternative crops to produce biofuels is critical and it is important that these crops meet a certain number of criteria. First, that these crops do not replace food crops on the same acres. Second, the these crops can grow on marginal lands such as CRP land. Third, that these crops require low inputs. To make a sustainable biofuel crop is critical, corn and soybeans are frankly too important as food crops to have them diverted to this other use. \n\nSo on one hand I agree with the author, but on the other hand, there is an opportunity for the right crop to help alleviate some of these issues, especially in areas where alternative cropping choices are limited. Since the middle ages, farmers have known that crop rotations maintain the vitality of the land. However, today in the U.S. many farmers are faced with a wheat on wheat rotation, making their crops suspect to diseases and ultimately lowering yields. Hopefully, solutions are on the horizon.
Avatar of: HEMMI BHAGAVAN

HEMMI BHAGAVAN

Posts: 1

March 16, 2010

The fact that combustion on biofuels also produces CO2 needs to be taken into account in any calculation.
Avatar of: Tarakad Raman

Tarakad Raman

Posts: 31

March 18, 2010

In the early days of corn-ethanol use in Brazil, I remember somebody having calculated that the total energy needed to produce the alcohol (e.g. for distillation) was more than the energy value of the product. My knowledge of the subject is outdated, will someone please update me?
Avatar of: anonymous poster

anonymous poster

Posts: 1

March 18, 2010

the current production methods are flawed, this is true. But the fact that biofuels are products of primary producers (plants), their carbon sequestration from photosynthesis needs to be included in the calculation. No one will agree that converting land from forest to monoculture is a sustainable production method of any crop. There are other alternatives, but without incentives from the markets (US/EU) habitat destruction will continue.

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