I wish the facts were different, but the latest analysis of biofuels is not encouraging. There was already concern as regards using food crops to produce ethanol. It meant that the food prices for that crop would increase (it has), that land use for crop production would increase (it has), and that fresh water usage would increase to support those crops (it has).
Now the latest issue of Science has published a study that says that the production of corn-based ethanol will effectively double the output of greenhouse gas emissions. This contradicts the earlier belief that it would reduce them by 15%.
It appears that a big contributor to the greenhouse gas output is the clearing of native forests and growth to grow the corn crops. The result: impacts on food crops and reductions in biodiversity.
A second study found that in Brazil more undeveloped land is being converted to produce sugarcane that is used to produce ethanol. This conversion releases huge amounts of CO2. So much that they estimate it would take 17 years of ethanol use to counter the effect.
A more dramatic example is where Malaysian and Indonesian peatlands are drained and cleared for the production of palm oil dumps so much CO2 into the atmosphere that the palm biodiesel produced would have to be burned for 450 years to counteract the CO2 release.
But all is not lost. We are early in our exploration of biofuels and what crops are used to generate those fuels. Researchers are looking for nonfood crops as well as refining waste products into biofuel. We just need to look carefully before we declare a free lunch.