That's easy - it's still hydrocarbon fuels. It doesn't do anything about greenhouse gases. In fact, it encourages them.
Negative on that. Here's the cycle.
1. Corn plants grow by extracting carbon from atmosphere
2. Turkey's eat the corn plants
3. Turkey guts get reprocessed into oil
4. SUV burns oil, returning carbon to atmosphere
It's a closed carbon cycle. The only time carbon gets added to the atmosphere is when something is fed into the machine that was originally manufactured from drilled oil. For example, plastic made from Texas crude; but that's no worse than the situation today. All other organic sources, slaughterhouse waste, sawmill waste, agro waste and sewage reprocessing represent a closed carbon cycle and a vast improvement in the global warming scenario.
Of course you know this means a new ice age is coming since we need increased atmospheric carbon to offset the previously scheduled ice age ;)