By David Suzuki with Faisal Moola

Earlier this year, when I crossed our great country to talk to Canadians about environmental issues, some media pundits took issue with our vehicle of choice — a diesel bus. Even when I explained that diesel actually has a lower carbon footprint than gasoline, some of them immediately shot back with — then why isn't it biodiesel?

In truth, we had actually wanted to showcase an alternative fuel like biodiesel, we just couldn't find a leasing agent who could get us an appropriate vehicle. But from the very beginning we were also nervous about highlighting something that might be more of a problem than a solution.

Turns out, we were probably right. According to a recent analysis published in the journal Science, attempting to save the planet by wholesale switching to biofuels like ethanol and biodiesel may unintentionally have the opposite effect.

Proponents of biofuels, which are often made from plants such as corn or sugar cane, often point to their many advantages over fossil fuels like gasoline. Biofuels are less toxic or non-toxic in comparison to fossil fuels. They are a renewable resource, whereas once fossil fuels are gone, they're gone. And biofuels can be grown just about anywhere you can grow crops, reducing the need for giant pipelines or oil tankers, and potentially helping to reduce conflicts in areas like the Middle East.

So far so good. But things start to get complicated when you look more closely. Much has already been debated about the energy requirements to produce some biofuels, especially corn-based ethanol. Ethanol made from corn only contains marginally more energy than what is needed to produce it. In fact, we use about a litre's worth of fossil fuels to grow, harvest, process, and transport a litre of corn-based ethanol. Many people argue that making corn-based ethanol is more of an agricultural subsidy for farmers than it is a sound environmental policy.

Things get even dodgier for biofuels when you look at the land area that would be needed to grow fuel crops. We use a lot of fossil fuels. Switching to biofuels would not reduce the demand for fuel, just change the way we get it. And that would require a lot of land. In fact, substituting just 10 per cent of fossil fuels to biofuels for all our vehicles would require about 40 per cent of the entire cropland in Europe and North America. That is simply not sustainable.

Of course, reducing the amount of fuel we use, no matter what the type, is very important. But the authors of the recent article in Science say that if our primary motive in switching to biofuels is to reduce global warming, then we have to look at all our options for the land that would be needed to grow fuel crops.

The authors conclude: "If the prime object of policy on biofuels is mitigation of carbon dioxide-driven global warming, policy-makers may be better advised in the short term (30 years or so) to focus on increasing the efficiency of fossil fuel use, to conserve the existing forests and savannahs, and to restore natural forest and grassland habitats on cropland that is not needed for food."

In other words, biofuels alone are not the quick-fix answer to global warming. In fact, strong legislated policies to improve the efficiency of our cars, homes and industries is a much more effective strategy. In the longer term, biofuels may certainly play an important role. Some technologies, like cellulosic ethanol, which is made from woody debris, are very promising and they need to be supported by government and industry now, so they can be available on a larger scale in the coming years. Biofuels have many advantages, but we have to look at all our options and make sure we make the best choices to ensure a more sustainable future.

September 14, 2007