Biofuels are not new. The engine invented in 1911 by Rudolf Diesel was made to run on peanut oil. However, cheap oil prices ensured that petrol became the fuel of choice to drive vehicles. For a variety of reasons, including rocketing oil prices, there is a global rush to biofuels. But they are not necessarily the panacea for dear transport fuel, gas-guzzling polluters or energy supply insecurity. A confidential World Bank report, details of which emerged yesterday, blames biofuels for pushing global fuel prices up by 75%. This is not what the supporters of biofuels, from governments to manufacturers, want to read.

Biofuels are not new. The engine invented in 1911 by Rudolf Diesel was made to run on peanut oil. However, cheap oil prices ensured that petrol became the fuel of choice to drive vehicles. For a variety of reasons, including rocketing oil prices, there is a global rush to biofuels. But they are not necessarily the panacea for dear transport fuel, gas-guzzling polluters or energy supply insecurity. A confidential World Bank report, details of which emerged yesterday, blames biofuels for pushing global fuel prices up by 75%. This is not what the supporters of biofuels, from governments to manufacturers, want to read.

Biofuels can be made from any organic source that can be rapidly replenished. In theory, they produce low net emissions of carbon dioxide as burning them recycles atmospheric carbon absorbed by the plant while growing. They are seen as sustainable, renewable and clean alternatives to fossil fuels as sources of energy. George W Bush has ordered that the US should replace 75% of imported oil with biofuel. In Britain, at least 2.5% of fuel sold on forecourts must come from crops such as soya or palm oil. The European Commission is aiming for 10% by 2020.

As the World Bank findings confirm, there is a price to pay for a stampede to biofuels. Farmland traditionally used for food and animal feed has been earmarked to grow biofuel crops. Farmers have been encouraged to set land aside for biofuel production. Grains have become a commodity on futures markets. Each factor has contributed to driving up the cost of food. The world's poor, who depend on staples such as rice, corn and soya, have been hit the hardest. Rising food prices have sparked riots in several countries, including Bangladesh, Pakistan and Mexico (where a quadrupling in the price of maize brought about civil unrest).

What price in political instability is the world prepared to pay for energy security? Is the goal of energy security really achievable with biofuels? Is there a cost in environmental terms from the so-called green option? The Royal Society, Britain's science academy, has concluded that some biofuels might cause more climate change than petrol because of the carbon emissions from fertilising, harvesting, processing and transporting biofuels. Also, a growing global appetite for biofuels adds to the risk of peatlands and rainforests being destroyed and turned over to crop-growing plantations.

Biofuels produce cheaper fuel and have a part to play in cutting greenhouse gas emissions in the industrialised and developing countries. But the World Bank report should be seen as a reminder of the dangers in a headlong rush towards biofuels as the answer to everything. Biofuels can cause their own ills, with potentially serious geopolitical and environmental consequences. It would be safer, greener and more sensible to set targets for cutting greenhouse gas emissions from transport fuels (by making cars twice as fuel-efficient, for instance) than for biofuel consumption. Consuming more of a different type of fuel might bring advantages but it brings problems, too. We must wake up to that.