The government’s scheme to introduce biofuels as a way to cut carbon emissions from road transport has led to extra emissions equivalent to putting 500,000 more cars on UK roads, according to environmentalists. A new study shows that producing the amount of biofuels required to meet the government’s targets in the past year could have inadvertently doubled the overall emissions of CO2 compared with the standard fossil fuels they have replaced. The extra emissions come from forest destruction tied indirectly to growing energy crops.