about 43 percent of current U.S. cropland devoted to growing corn would be needed for supplying ethanol refineries.

The Nature Conservancy report suggests that by replacing forests and
grasslands, we'd likely see an increase, not a decrease, in carbon
dioxide production for 93 years. The Princeton study says it's more
like 167 years

about 43 percent of current U.S. cropland devoted to growing corn
would be needed for supplying ethanol refineries.