The problem is that advocates of reducing the greenhouse effect by promoting bio-fuels production have not made clear where the land will come from. In principle, there are only three ways to procure it: by withdrawing it from food or fodder production, from the production of natural materials – particularly wood – or from nature.
问题在于提倡通过推广生物燃料的生产来降低温室效应的人没有明确土地应该从哪里来。原则上，土地的来源只有三个途径：从生产食品或饲料、生产天然材料，尤其是木材的土地或是从自然中获取。