from sugarcane in Brazil. Europe produces somewhat less biofuels, although still a considerable amount, mainly in the form of vegetable oil for biofuel.

Many governments around the world have either goals or mandates for biofuels, Searchinger said, and if these goals and mandates are met, biofuels will account for about 10 percent of the world’s transportation fuels by 2020. This represents about 2.5 percent of the world’s total energy budget, but Searchinger said, when the energy that it takes to make biofuels is taken into account, biofuels would be providing about 1.7 percent of the world’s delivered energy by 2020.

How much of the world’s crops would that take? By 2020 biofuels would require that about 26 percent of all the energy contained in the present production of the world’s crops. By 2050 that figure would rise to 36 percent, he added. “So, that gives you some idea of the challenge, which is that it takes a large amount of biomass to get a small amount of energy.”

Of course, liquid biofuels are only one form of bioenergy that people are interested in, he noted. For example, there is also a big push in Europe as well as in some U.S. states to produce electricity from wood products.

Governments are encouraging the use of bioenergy in various ways. The European Commission has required, for instance, that 20 percent of all energy in Europe be renewable by 2020—not just the energy from utilities, but all energy. It is expected now that more than half of that will come from bioenergy, Searchinger said. A number of states have renewable energy targets, he said, although they are not quite as stringent and are just for electricity.

The Effect of Biofuels Usage on Carbon Dioxide Levels

One of the main reasons that people support the use of biofuels, Searchinger said, is the belief that “when you switch from burning a fossil fuel to burning a biofuel you get some kind of direct greenhouse gas benefit.” But, he said, a close examination indicates that this is not the case and that the belief that there is a direct benefit stems from an “accounting error.”

The belief that burning biofuels contributes less carbon dioxide to the atmosphere than burning fossil fuels stems from the fact that biofuels are derived from plants, which absorb carbon dioxide as they grow. “So, the theory is that, in effect, bioenergy is just recycling carbon, not

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