NAIROBI - Countries must adopt a much more sophisticated approach to developing biofuels as a green energy option if they are to benefit the economy, the environment and society as a whole, the United Nations said Friday.

Biofuels are mostly produced from food crops including wheat, maize, sugar cane and vegetable oils, and advocates have hailed them as an important way to cut greenhouse gas emissions that contribute to climate change.

But others argue that they may actually worsen the situation by leading to the destruction of ecosystems, offer limited energy savings and divert crops from a food chain already struggling to meet the demands of a growing global population.

A major U.N. Environment Program (UNEP) report Friday said biofuels, like all new technologies, presented opportunities and challenges.

Therefore a more sophisticated debate is urgently needed, UNEP Executive Director Achim Steiner told reporters.

On one level, it is a debate about which energy crops to grow and where, and also about the way different countries and biofuel companies promote and manage the production and conversion of plant materials for energy purposes. Some clearly are climate friendly, while others are highly questionable.

Steiner said it also involved a choice about how to use finite land resources and balance competing interests in a world of 6 billion people, rising to more than 9 billion by 2050.

The report makes it clear that biofuels have a future role, but also underlines that there may be other options for combating climate change, improving rural livelihoods and achieving sustainable development that may, or may not, involve turning ever more crops and crop wastes into liquid fuels.

BIODIVERSITY LOSS

The study, the first by UNEP's International Panel for Sustainable Resource Management, said some first generation biofuels such as ethanol from sugar cane could have positive impacts in terms of greenhouse gas emissions.

But it said that the way biofuels were made determined whether they led to fewer emissions or made matters worse.

It cited the production and use of biodiesel from palm oil on deforested tropical peatlands, which it said could lead to significant increases in greenhouse gas emissions -- up to 2,000 percent or more when compared with fossil fuels.

Generating electricity at power stations using wood, straw, seed oils and other crop or waste material was generally more energy efficient than converting biomass to liquid fuels.

Dr Stefan Bringezu of the panel's Biofuels Working Group said that if the world's farmland was to be used to feed a growing population, and one increasingly consuming meat, any extra demand for energy crops would almost inevitably increase pressure on grasslands, savannahs and forests.

This will lead to more greenhouse gas emissions as well as rising losses of biodiversity, Bringezu said.

Using wastes and residues represents one safer and more sustainable path out of this dilemma.

(Editing by Jon Boyle)

Energy