Read the following on the GHG impacts of U.S. ethanol production for Thursday, Feb. 21:
Start with an abstract in the periodical Science::
http://www.sciencemag.org/cgi/content/abstract/1151861Now read this summary from the New York Times:
February 8, 2008
Studies Call Biofuels a Greenhouse Threat
By ELISABETH ROSENTHAL
Almost all biofuels used today cause more greenhouse gas emissions than conventional fuels if the full emissions costs of producing these ''green'' fuels are taken into account, two studies published Thursday have concluded.
The benefits of biofuels have come under increasing attack in recent months, as scientists took a closer look at the global environmental cost of their production. These latest studies, published only by the journal Science, are likely to add to the controversy. These studies for the first time take a detailed, comprehensive look at the emissions effects of the huge amount of natural land that is being converted to cropland globally to support biofuel development.
The destruction of natural ecosystems -- whether rain forests in the tropics or grasslands in South America -- not only releases greenhouse gases into the atmosphere when they are burned and plowed, but also deprives the planet of natural sponges to absorb carbon emissions. Cropland also absorbs far less carbon than the rain forests or even scrubland that it replaces.
Together the two studies offer sweeping conclusions: It does not matter if it is rain forest or scrubland that is cleared, the greenhouse gas contribution is significant. More important, they discovered that, globally, the production of almost all biofuels resulted, directly or indirectly, intentionally or not, in new land's being cleared for food or fuel.
''When you take this into account, most of the biofuel that people are using or planning to use would probably increase greenhouse gases substantially,'' said Timothy Searchinger, lead author of one of the studies and a researcher in environment and economics at Princeton.
These plant-based fuels were originally promoted as better than fossil fuels because the carbon released when they were burned was balanced by the carbon absorbed when the plants grew. But even that equation proved overly simplistic because the process of turning plants into fuels causes its own emissions -- for refining and transportation, for example.
The clearance of grassland releases 93 times the amount of greenhouse gas that would be saved by the fuel made annually on that land, said Joseph Fargione, lead author of the second paper, and a scientist at the Nature Conservancy. ''So for the next 93 years you're making climate change worse, just at the time when we need to be bringing down carbon emissions.''
In the wake of the new studies, 10 eminent United States' ecologists and environmental biologists on Thursday sent a letter to President Bush and the speaker of the House, Nancy Pelosi, urging a reform of biofuel policies. ''We write to call your attention to recent research indicating that many anticipated biofuels will actually exacerbate global warming,'' the letter said.
The European Union and a number of European countries have recently tried to address the land-use issue with proposals stipulating that imported biofuels cannot come from land that was previously rain forest.
But even with such restrictions in place, Dr. Searchinger's study shows, the purchase of biofuels in Europe and the United States leads indirectly to the destruction of natural habitats far afield.
For instance, if vegetable oil prices go up globally, as they have because of increased demand for biofuel crops, more new land is inevitably cleared as farmers in developing countries try to get in on the profits. So crops from old plantations go to Europe for biofuels, while new fields are cleared to feed people at home.
Likewise, Dr. Fargione said that the dedication of so much cropland in the United States to growing corn for bioethanol had caused indirect land use changes far away, for instance, by increasing pressure on Brazil to meet soybean demand. ''Brazilian farmers are planting more of the world's soybeans -- and they're deforesting the Amazon to do it,'' Dr. Fargione said.
Industry groups, like the Renewable Fuels Association, immediately attacked the new studies as ''simplistic.''
''Biofuels like ethanol are the only tool readily available that can begin to address the challenges of energy security and environmental protection,'' said Bob Dineen, the group's director, in a statement after Science released the reports.
But the papers suggested that, if land use is taken into account, biofuels may not provide all the benefits once anticipated.
Dr. Searchinger said the only possible exception he could see for now was sugar cane grown in Brazil, which take relatively little energy to grow and is readily refined into fuel. He added that governments should focus on developing biofuels that did not require cropping, such as those from agricultural waste products. ''This land-use problem is not just a secondary effect -- it was often just a footnote in prior papers,'' Dr. Searchinger said. ''It is major.''
Copyright 2008 The New York Times CompanyWe will start class with a brief quiz on the material.
Extra material of interest: many academics and others find the "mainstream media" such as the New York Times to be an increasingly poor source of news and analysis. The right weblogs are starting to take over in terms of accuracy and representation of key viewpoints. (This is neither a liberal or conservative comment -- it's primarily about quality.) Compare the
NYT article above, for example, this one at
WiredScience. Here we learn about key assumptions (particularly growth in crop yields), and work by other, competing research groups. Interestingly, neither mentions the
subsidies ,
mandates (that's command and control), and
tariffs which are the reason we produce ethanol in the first place!
