Britain is stepping up the use of biofuels with new targets in the coming weeks - as the first step toward meeting an EU directive that five percent of all transport fuels come from renewable energy sources by the year 2010. Tendai Maphosa takes a closer look at the pros and cons of biofuels in this report from London.

Efforts to find sustainable, renewable sources of energy are growing and at the center of that trend is the switch from fossil fuels to biofuels, which are derived from crops such as corn, sugar cane and palm oil.

From April 15, 2,5 percent of all gasoline and diesel fuel sold in Britain must be derived from crops.

Several scientists say the use of fossil fuels is a big contributor to climate change. They also agree that use of biofuels could lead to a reduction of harmful carbon emissions released into the atmosphere by fossil fuel use. But lately, some scientists have raised concerns that biofuels could have a devastating social and environmental impact.

Earlier this year, the British parliament's Environmental Audit Committee issued a report calling for a moratorium on the introduction of the 2.5 percent target. Speaking with VOA in London, Committee Chairman Tim Yeo explains why.

"Our concern was that the target which both the European Union and Britain have set to increase the amount of biofuels that are going to be used is endangering certain parts of the world, particularly rainforests and parts of the developing world where land may be turned over from food production to growing energy crops and we feel that this is an unsustainable policy," he said.

Calls for postponing the biofuel target have come from environmental groups such as Greenpeace and Friends of the Earth and humanitarian organizations such as Oxfam and the Catholic Agency for Overseas Development.

Professor Robert Watson, the chief scientific adviser to Britain's Department for Environment, Food and Rural Affairs (DEFRA) also expressed concern over the introduction of biofuels in their present form. He told VOA the sustainability of biofuels should be assessed before introducing a mandated target for their use.

"We have to ask the question, 'Will it lead to tropical deforestation?' and if it does, it leads to carbon dioxide being emitted into the atmosphere," he said. 'Do we need to use fertilizers, which might emit nitrous oxide into the atmosphere, which is a very strong greenhouse gas?' 'Will it lead to soil erosion, which will be environmentally unsustainable, could it lead to loss of biological diversity?' So there is a number of environmental issues we need to look at."

In addition, Watson says the use of food crops for biofuels could force prices higher, resulting in food shortages and increased hardships for the poor.

But Watson says some biofuels are sustainable. Among that category is 'jatropha,' a non-food plant being promoted by Ron Oxburgh, former chairman of the oil giant subsidiary, Shell U.K. Oxburgh now heads D1 oils, a company involved in biofuel research.

"D1 Oils is working with what we call a second-generation fuel," he said. "This is biodiesel produced from the fruit of the jatropha tree and that is a tree that does not need a lot of water and tends to grow on marginal and degraded land in the tropics."

Oxburgh explains that the first generation biofuels are those mainly derived from food crops. He too worries that emphasizing their use would lead to a food crisis. But, he acknowledges that it will be another two years before biodiesel can be commercially produced from the jatropha tree.

British parliament member Tim Yeo says he fears biofuels will not be the solution.

"At the moment, we think the policy will be damaging in terms of its impact on the environment and for that reason it needs to be changed very urgently," he said.

Yeo says the emphasis at the moment should be the improvement of low-emission vehicles and increasing the range of electric cars.

The Department for Transport, which is responsible for vehicle fuels, did not respond to VOA's requests for an interview.

But government environmental advisor Robert Watson praised the government for asking the Renewable Fuels Agency to carry out an in-depth independent analysis into the environmental and social impact of biofuels.

"I am extremely pleased that the government has asked for this very thorough review, other government scientific advisors such as myself are being asked to review that report as its being drafted, so that as we move forward into the future the only biofuels we source are both environmentally and socially sustainable," he said.

Late last year, Prime Minister Gordon Brown said Britain would not support an increase in biofuels over current target levels until an effective standard is in place.