With their environmental bonafides in question and without a profitable business model, it's possible that current biofuels could be a bad idea, regardless of their impact on the world's food system.
Bad idea? Horrible idea is more like it.
What will happen when the food industry is presented with the option of selling crops for fuel for a high profit or crops as food for a lower margin? They'll will inevitably choose the first option.
The rising cost of food puts quite a strain on the entire economic balance. If food becomes more expensive it impacts buying power, since people have to spend more money just feeding themselves. With less buying power companies sell less. With less sales there are two possible options: increasing profit margins (aka: cutting costs or pumping prices) or go out of business. It creates a vicious cycle.
Then there's fact that biofuels are not at all greener than fossil fuels.
Within that same "not that green" line of thought lies the menace of monocultures. Having the same crop growing on the same piece of ground growing over and over and over again kills the soil. When the soil stops being as productive farmers inject fertilizers. That keeps them rolling for a while, until it becomes saturated enough for people to walk away from that plot. What is left is not a nice sight. (and this I've seen with my own eyes, no one needs to convince me of its impact).
Another thing to take into account is that a high proportion of crops are raised in 3rd world countries. 3rd world countries have systemic corruption. Corruption plus oportunity for proffitability with disregard of laws equals a nasty situation. (Blood diamonds, anyone?)
To this day I wonder how European legislators could be so short sighted. And I say "European" because the so-called Greens have stronger influence on the EU.
Famous last words: bio-fuels replace a tough problem with a worst one.