That's a very important point, and i should have mentioned it in my comment. In 100 years the poor countries will be much richer, and we have opportunity to help improve their situation sooner which in turn would help everyone by making markets larger and increasing the number of people working on science. In some cases helping this countries directly will have more effect than wasting money on biofuel subsidies. Bjørn Lomborg have many interesting talks/writings about this issue.