The Economist, 08/10/2009
How green is ethanol? The Renewable Fuels Association (RFA), an American lobby for the stuff, obviously wants voters and politicians to think it is very green indeed. The association’s cool-coloured website plays down claims that ethanol may actually harm the environment. The biggest target of those claims these days is that growing maize to make ethanol causes indirect changes in land use by altering the incentives of other, often foreign, farmers.
Adding ethanol to the traditional markets for maize (food and fodder) inevitably pushes the price up. That encourages farmers, including those in poor countries, to boost production. If some of those farmers plough up savannah or cut down forest to grow the extra crops, the carbon dioxide released from the plants destroyed and soil ploughed up reduce the benefits of substituting the ethanol produced for petrol. If forests that are still growing are cleared, the environment loses the effect of their future uptake of carbon dioxide, too.