Via the LA Times, this is the best news I've heard all day:
The Obama administration on Tuesday proposed renewable fuel standards that could reduce the $3 billion a year in federal tax breaks given to producers of corn-based ethanol. The move sets the stage for a major battle between Midwest grain producers and environmentalists who say the gasoline additive actually worsens global warming.
....While biofuels as a whole — including grasses and even algae — are considered promising alternatives to petroleum, some researchers have begun challenging the use of corn for this purpose.
In particular, they point to the "indirect land-use" effects of pulling corn out of the world food supply, which could force farmers in developing nations to clear rain forests — and release massive amounts of carbon dioxide in the process — in order to plant corn.