Answer:If biofuels are produced from feedstocks that would have been used for food, then biofuels directly reduce potential food supplies. This reduction occurs even if feedstock price increases result in an expansion of supply because the expanded feedstock supply will typically reduce the supply of other food crops.
Evidence remains limited on the impacts specifically associated with intensified biofuel production, although most of the problems are similar to those already associated with agricultural production – water depletion and pollution, soil degradation, nutrient depletion and the loss of wild and agricultural biodiversity.Specifically, using corn and other food crops to make fuel can raise food prices, pollute water systems, and lead to land-use changes that increase global warming pollution. Sustainable expansion of biofuels requires moving beyond food-based fuels like corn ethanol, and toward cleaner, non-food based biomass resources.