Last Updated: Friday, 22 September 2006, 08:07 GMT 09:07 UK

Biofuels: Green energy or grim reaper?

Biofuels could end up damaging the natural world rather than saving it from global warming, argues Jeff McNeely in the Green Room. Better policies, better science and genetic modification, he says, can all contribute to a greener biofuels revolution.

With soaring oil prices, and debates raging on how to reduce carbon emissions to slow climate change, many are looking to biofuels as a renewable and clean source of energy.

The European Union recently has issued a directive calling for biofuels to meet 5.75% of transportation fuel needs by 2010. Germany and France have announced they intend to meet the target well before the deadline; California intends going still further.

This is a classic "good news-bad news" story.

Of course we all want greater energy security, and helping achieve the goals (however weak) of the Kyoto Protocol is surely a good thing.

However, biofuels - made by producing ethanol, an alcohol fuel made from maize, sugar cane, or other plant matter - may be a penny wise but pound foolish way of doing so.

Consider the following:

• The grain required to fill the petrol tank of a Range Rover with ethanol is sufficient to feed one person per year. Assuming the petrol tank is refilled every two weeks, the amount of grain required would feed a hungry African village for a year
• Much of the fuel that Europeans use will be imported from Brazil, where the Amazon is being burned to plant more sugar and soybeans, and Southeast Asia, where oil palm plantations are destroying the rainforest habitat of orangutans and many other species. Species are dying for our driving
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• If ethanol is imported from the US, it will likely come from maize, which uses fossil fuels at every stage in the production process, from cultivation using fertilisers and tractors to processing and transportation. Growing maize appears to use 30% more energy than the finished fuel produces, and leaves eroded soils and polluted waters behind
• Meeting the 5.75% target would require, according to one authoritative study, a quarter of the EU's arable land
• Using ethanol rather than petrol reduces total emissions of carbon dioxide by only about 13% because of the pollution caused by the production process, and because ethanol gets only about 70% of the mileage of petrol
• Food prices are already increasing. With just 10% of the world's sugar harvest being converted to ethanol, the price of sugar has doubled; the price of palm oil has increased 15% over the past year, with a further 25% gain expected next year.

Little wonder that many are calling biofuels "deforestation diesel", the opposite of the environmentally friendly fuel that all are seeking.

With so much farmland already taking the form of monoculture, with all that implies for wildlife, do we really want to create more diversity-stripped desert?

Others are worried about the impacts of biofuels on food prices, which will affect especially the poor who already spend a large proportion of their income on food.

Biotech boost

So what is to be done? The first step is to increase our understanding of how nature works to produce energy.

Amazingly, scientists do not yet have a full understanding of the workings of photosynthesis, the process by which plants use solar energy to absorb carbon dioxide and build carbohydrates.

Biotechnology, its reputation sullied by public protests over GM foods, may make important contributions. According to the science journal Nature, recombinant technology is already available that could enhance ethanol yield, reduce environmental damage from feedstock, and improve bioprocessing efficiency at the refinery.

The Swiss biotech firm Syngenta is developing a genetically engineered maize that can help convert itself into ethanol by growing a particular enzyme.

Others are designing trees that have less lignin, the strength-giving substance that enables them to stand upright, but makes it more difficult to convert the tree's cellulose into ethanol.

Some environmentalists are worried that these altered trees will cross-breed with wild trees, resulting in a drooping forest rather than one that stands tall and produces useful timber and wildlife habitat.

In the longer run, biotech promises to help convert wood chips, farm wastes, and willow trees into bioethanol more cheaply and cleanly, thereby helping meet energy needs while also improving its public image.

Public stake

But that is not nearly enough; bioenergy is too important to be left in the hands of the private sector.

Many of the social and environmental benefits of bioenergy are not priced in the market, so the public sector needs to step in to ensure these benefits are delivered.

An easy immediate step would be to mandate improved fuel efficiency for all forms of transport, beginning with the private automobile. A 20% increase in fuel-efficiency standards is feasible using current technology, and would save far more energy than Europe's biomass could produce.

Governments also need to provide leadership in the form of economic incentives to minimise competition between food and fuel crops, and ensure that water, high-quality agricultural land, and biodiversity are not sacrificed on the altar of our convenience.

Calculations of energy return on investment need to include environmental impacts on soil, water, climate change, and ecosystem services.

The bottom line is that biofuels can contribute to energy and environmental goals only as part of an overall strategy that includes energy conservation, a diversity of sustainable energy sources, greater efficiency in production and transport, and careful management of ethanol production.

Jeffrey A McNeely is chief scientist of IUCN, the World Conservation Union, based in Switzerland

The Green Room is a series of opinion articles on environmental topics running weekly on the BBC News website