OK, so maybe it wasn't such a good idea to grow agricultural crops in order to be able to fuel my car. I realise that using agricultural land to grow biofuel does compete with other crops that feed man and beast. Let's call it ILUC (indirect land use change) - and make it very complicated.
What I don't understand is why biofuel crops (oilseed, oil palm, sugarcane and corn/wheat) are the only crops that are unwanted. Cotton you say is OK, because of course we need clothes, but hey we can wear clothes made from woodfibres/viscose or made from crude oil we pump out of the ground aka nylon. No need to wear these agriculturally grown fibres? When we wash our hands or hair in the bath, did anyone ever cry ILUC? As well as for biodiesel the oil crops are also the only feedstock for production of a whole range of soaps, shampoos and technical products that we like to use. We could also use products derived from mineral oil, but we prefer the natural products.
I think it is amazing how the green troops have managed to set the agenda selectively. The reality is that no matter what we do when we try to manage nature, we will get negative side effects.
Let's take a look at the next big thing. Everybody agrees that it would be just wonderful if we could "just" make biofuel from cellulosis and agricultural waste. Has anybody tried to calculate how much wood waste would be necessary to "feed the beast"? Wikipedia suggests that close to 20% of US land (similar to the area used to grow crops) would be needed to cover US transportation fuels from ethanol from switchgrass - quite significant numbers - that will definitely have a significant ILUC effect.
What will happen to the ecosystem and the nutrient content of the soil if much more of the biomass is removed from the land in order to be processed/turned into biofuel? Well - the soil is going to be deprived of organic material, which constitutes an important part of the slow release system for nutrients and water of the soil - also known as humus. Depriving the soil of the organic material will be slowly spoiling the carrying capacity of the soil.
Using wood and forest by-products has similar problems. Enormous quantities are needed, there will be competition with other uses of forest products, from firewood, over cellulosis to fibreboards and construction wood. And the forest is potential agricultural land and vise versa - so also an ILUC effect here. I guess our politicians are in for a tough job to find the "good" solution to our energy and transport fuel problems. Unfortunately they are not going to get any help from the green NGOs.
Update: A German view on the same issue comes to largely the same conclusion.
