Ecological Sustainability

127Mitigations of Human Impacts through Technology

ethanol. Table 4.3 illustrates the estimated net energy gain ratio (the “energy

balance”) for various fuels, that is, the ratio of the fuel energy output to the

total energy input in producing that fuel.

Searchinger et al. (2008) concluded that once direct and indirect effects of

land use changes were considered in the life cycle assessment of biofuel addi-

tives in gasoline, instead of saving, both corn kernel and CE use increase net

carbon emissions compared to pure gasoline, by 93% and 50%, respectively.

In a second paper published in the same issue of Science as Searchinger et al.,

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