Biofuels and Food Prices Scott Simon speaks with ecologist David Tilman about how much biofuels benefit the environment, and whether growing crops for biofuel manufacturing could drive up food prices.

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Biofuels and Food Prices

Biofuels and Food Prices

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Scott Simon speaks with ecologist David Tilman about how much biofuels benefit the environment, and whether growing crops for biofuel manufacturing could drive up food prices.


With oil prices hovering just below $100 a barrel, the push to find other sources of energy like biofuels is intensified. Several Hollywood and Nashville stars boast of converting their huge plush cars to run on ethanol. But are biofuels really better for the environment, and can they be even worse for food prices?

David Tilman is an ecologist at the University of Minnesota. This year, he's a visiting fellow at the Environmental Institute at Princeton University. He joins us from there.

Professor Tilman, thanks very much for being with us.

Dr. DAVID TILMAN (Ecology, University of Minnesota; Visiting Fellow, Environmental Institute, Princeton University): My pleasure.

SIMON: Ethanol - of course, derived from corn - is the biofuel we hear about most, especially on the campaign trail with Iowa holding caucuses. How does ethanol affect the supply and cost of food?

Dr. TILMAN: Corn is a major source of food for the U.S. and the world. Corn is what feeds the chickens, the pigs, the cattle - that gives us much of our meat. We also use corn to make high-fructose corn syrup that's used in many foods and soft drinks. When the price of corn goes up, the price of all of these foods go up. The same thing happens even to a greater extent for people who literally eat corn - in Mexico in Central America where they eat corn tortillas. That's a staple of their life. And that price has really gone up.

SIMON: And so the price of food among people living in the developing world has gone up, can we fairly say, because people are using ethanol to burn in their cars?

Dr. TILMAN: Absolutely. And this is just the beginning. If you look at the projections of how much ethanol Congress would like to have made, if we make it from food crops - which is what we're doing right now - we're going to have the price of food pegged to the price of energy. At $100 a barrel, that will be difficult for some Americans but impossible for probably the one-third poorest people of the world.

SIMON: Is ethanol or biofuels, in fact, better for the environment?

Dr. TILMAN: A little bit. The governor of my state describes them as a Model T biofuel, which is they say they barely work but they're probably better than the horses we had before then. It takes a lot of energy to grow corn. And it takes even more energy to convert that corn into ethanol. By the time we're done, if you look at the total energy in a gallon of ethanol, only 20 percent of that is new energy. Eighty percent is the fossil energy we had to use to grow the corn and make that fuel. That's not much of a gain.

On the environmental side, when you burn these fossil fuels, you're really seeing carbon dioxide into the air. If you look at — across the whole life cycle of growing corn, making ethanol and burning it in a car, and compare that to what happens when you find oil and make gasoline and burn it in a car, you only have about 15 percent less greenhouse gas going into the air from burning ethanol than you would if you're burning gasoline.

SIMON: Are there some biofuels that might be better than others?

Dr. TILMAN: There's a lot of optimism about what are called the next generation of biofuels. If we grow biofuels in ways that require very low input of fossil energy to grow them, which we can do, let's say, if we grow things like perennial plants where we don't need to plant them every year. And if we use their biomass directly and not just the seed - all we use are the seed of the corn - we use their biomass directly to make energy and to run the plant that makes the energy, we can have biofuels that are immensely better, that can give us 80 or 90 percent reductions in greenhouse gases compared to gasoline.

SIMON: Is it practical, Professor Tilman, to think that fossil fuels can be replaced by biofuels?

Dr. TILMAN: No. Not with how much fossil fuel we're using right now. If we make biofuels in a way that still lets us be able to have the food that the world demands and to have other environmental services that the world demands, biofuels are going to be a niche product. They will meet maybe 10 to 20 percent of global energy needs. We have to have big increases in energy efficiency in our homes, in our transportation, in factories and so on. And we have to have other forms of renewable energy - wind energy, solar energy. And we have to have, probably, nuclear energy also, which is not renewable but can go on for a long time for us to meet all of our energy needs.

You know, there are 6 billion people. We're heading toward 9 billion people. It's incredible what 9 billion people are going to consume. To meet those needs in a way that has a sustainable Earth, we're going to have to find many, many niche solutions which, in total, together, can let us achieve the sustainability we all want.

SIMON: David Tilman, professor of ecology at the University of Minnesota, currently at the Environmental Institute at Princeton.

Thanks very much.

Dr. TILMAN: Well, thank you.

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