The EU is to re-examine its policy on biofuels after admitting that the environmental and social impact of producing the crops may be greater than originally thought, it emerged today.
The European commission's environment minister, Stavros Dimas, admitted that the EU did not foresee the problems that would be raised by its policy of getting 10% of Europe's road fuels from plants by 2020.
He said the environmental impact and the effect on poor communities of boosting biofuel production would be greater than Brussels had originally thought.
The acknowledgement, in an interview for the BBC, follows a report published in the journal Science last week which warned that biofuels made from corn, sugar cane and soy could have a greater environmental impact than burning fossil fuels.
The research, from the Smithsonian Tropical Research Institute in Panama, found that although the fuels themselves emitted fewer greenhouse gases, they all had higher costs in terms of biodiversity loss and destruction of farmland.
"Regardless of how effective sugar cane is for producing ethanol, its benefits quickly diminish if carbon-rich tropical forests are being razed to make the sugar cane fields, thereby causing vast greenhouse-gas emission increases," the report's authors, Jörn Scharlemann and William Laurance, wrote.
Another scientific study published last August also warned that the target of getting 10% of petrol and diesel needs from renewable sources by 2020 was less effective in curbing carbon emissions than a programme of restoring forests and protection plant habitats.
Dimas said today that there had been "a lot of enthusiasm" for the biofuels option a year and a half ago as a means of meeting overall targets in cutting emissions from vehicles.
That enthusiasm had "gone down" because of revelations that the environmental and social problems were greater than thought.
"We have seen that the environmental problems caused by biofuels and also the social problems are bigger than we thought they were," he told the BBC.
Dimas said the commission would now have to "move carefully" on the issue of biofuels, adding: "We have to have criteria for sustainability, including social and environmental issues, because there are some benefits from biofuels."
One of the criteria in pushing biofuels was that the policy had to be "sustainable" - meaning that harnessing biofuels should not mean clearing existing forest land.
If the necessary sustainability could not be achieved, said Dimas, the EU targets would not be met.
Greenpeace's executive director, John Sauven, said: "The dangers of mass biofuel production need to be taken seriously because as things stand biofuels could be worse than useless at combating climate change.
"But UK government targets mean that soon motorists will be forced to pump these fuels into their tanks, with no way of knowing where they're coming from. We need to be sure that when we fill up we are not trashing the world's rainforests. A better, quicker solution would be to make our cars far more fuel efficient."
The earlier study, published in Science last August, warned that the European biofuels policy was a "mistake".
It compared the relative environmental benefits of growing crops on arable land to produce biofuels, or replanting the same land with trees, and found that the quantity of CO2 absorbed by forests over 30 years would be "considerably greater" than the emissions avoided by using biofuels.The extent of the benefits of biofuels will be assessed in a review being published today by the Royal Society. The report is expected to urge EU governments to ensure that they only endorse a biofuels policy which can be proven to cut carbon emissions.