Biofuels present many opportunities as well as challenges, requiring "a more sophisticated debate" as to their merits as a green energy option, according to a U.N. Environment Program report. "The report makes it clear that biofuels have a future role, but also underlines that there may be other options for combating climate change, improving rural livelihoods and achieving sustainable development that may, or may not, involve turning ever more crops and crop wastes into liquid fuels," said UNEP Executive Director Achim Steiner.
The biggest obstacle to a Copenhagen climate deal may be how to pay for the costs of helping developing countries convert to cleaner tech as well as helping the poorest countries deal with the effects of climate change. The U.S. and European countries have agreed to pay those costs, but there's no concrete plan for where the money will come from.