That's too bad. I'm sure that ther's probably more factors in the overall greenhouse effect but they just aren't brought up. Another article about this too.
http://www.greencarcongress.com/2008/02/new-studies-ide.html
Searchinger et. al. note in their paper that “land use change emissions” refers to all of the carbon storage and ongoing sequestration that is foregone by devoting land to the production of biofuels. Using land to produce a biofuel feedstock forgoes some of that storage and ongoing sequestration, causing offsetting emissions in a variety of ways.
A forest or grassland can be directly converted to grow a biofuel such as corn, resulting in the direct loss of the carbon in the standing trees and grasses and a fair chunk of the carbon after plowing up the soils. Soils store major quantities of carbon in forests and grasslands.
The same land, if not devoted to biofuels, could continue to sequester carbon. For example, a young, growing forest will continue to sequester carbon as the forest grows for many years. This ongoing sequestration is lost if the land is converted to a biofuel for ethanol. (Although land converted to grow the biofuel, such as corn, will continue to sequester carbon, the typical biofuel analysis already takes account of that carbon.)
Both of these effects can occur indirectly. For example, if corn in the United States is diverted to ethanol production, grasslands or forest could be converted anywhere in the world to replace the corn. Complicating this analysis, these indirect effects can pass through many steps. For example, soybean land in the US can be planted in corn, and forest or grassland plowed up in Brazil to replace the soybeans.
In essence, under typical biofuel calculations, the carbon withdrawn from the atmosphere by growing the feedstock becomes a greenhouse gas credit. We call this credit a feedstock uptake credit, which we treat as part of the overall land use effect. But the world’s land already exists, and that land is for the most part removing carbon from the atmosphere each year and in most cases has stored substantial amounts of carbon for decades that may be lost if used to produce biofuels.
The proper focus must be on the net change in carbon removed from the atmosphere that is either stored by land or used to replace fossil fuels. (Replacing fossil fuels is a form of storage because the unneeded fossil fuel remains stored underground.) An accurate accounting must subtract the emissions from land use change from the feedstock uptake credit to produce a proper net estimate of the overall land use effect—the effect of using land to produce biofuels.
