In 2013 the U.S. used 4.7 billion bushels of corn (40% of the harvest) to produce over 13 billion gallons of ethanol fuel. Source: YES! Magazine
The Intergovernmental Panel On Climate Change (“IPC.”) in its Reports (WGI and WGIII) said, “Biofuels have direct, fuel‐cycle GHG emissions that are typically 30–90% lower than those for gasoline or diesel fuels. However, since for some biofuels indirect emissions—including from land use change—can lead to greater total emissions than when using petroleum products, policy support needs to be considered on a case by case basis” (IPCC 2014 Chapter 8).
Did you get that? Biofuels can lead to greater total emissions than petroleum products.
The summary in the report also states, “Increasing bioenergy crop cultivation poses risks to ecosystems and biodiversity” (WGIII).
“Many potential negative risks of development, such as direct conflicts between land for fuels and land for food, other land-use changes, water scarcity, loss of biodiversity and nitrogen pollution through the excessive use of fertilizers,” The reports and their short discussion of biofuels have ignited a fierce debate as to whether they’re of any environmental benefit at all.
Ok, if you are still not convinced…
The International Institute for Sustainable Development was not so diplomatic, and estimates that the CO2 and climate benefits from replacing petroleum fuels with biofuels like ethanol are basically zero (IISD). They claim that it would be almost 100 times more effective, and much less costly, to significantly reduce vehicle emissions through more stringent standards, and to increase CAFE standards on all cars and light trucks to over 40 miles per gallon as was done in Japan just a few years ago.
With more than 60 nations having biofuel mandates, the competition between ethanol and food has become a moral issue. Groups like Oxfam and the Environmental Working Group oppose biofuels because they push up food prices and disproportionately affect the poor.
In summary…Most importantly, the new IPCC report is a complete about-face for the UN’s Panel. Its 2007 report was broadly condemned by some environmentalists for giving the green light to large-scale biofuel production, resulting in environmental and food supply problems.
Sources: http://www.ipcc.ch/report/ar5/wg1: “It’s Final — Corn Ethanol Is Of No Use,” by James Conca, Forbes, March 16, 2016