NARRATOR：

Now listen to part of a lecture on the topic you just read about.

MALE PROFESSOR：

Ethanol actually is a good alternative to gasoline.

Although you just read three reasons why it’s not a good alternative, not one of these three reasons is convincing:

First, the increased use of ethanol fuel will not add to global warming.

It’s true that when ethanol is burned, it releases carbon dioxide into the atmosphere.

But as you read, ethanol’s often made from plants such as corn.

Well, the process of growing the plants counteracts this release of carbon dioxide.

Let me explain. Every growing plant absorbs carbon dioxide from the air as part of its nutrition.

So, growing plants for ethanol production actually removes carbon dioxide from the atmosphere.

Second, large-scale production of ethanol doesn’t have to reduce the sources of food for animals.

That’s because we can produce ethanol using cellulose.

Cellulose is the main component of plant cell walls, and you’ll find most cellulose in those parts of plants that are not eaten by animals.

So, since we can produce ethanol from the plant parts that aren’t eaten, the amount of animal feed that’s available will not be reduced.

Third, in the future, ethanol will be able to compete with gasoline in terms of price.

It’s true that government subsidies make ethanol cheaper than it would normally be, but this support won’t always be needed.

Once enough people start buying ethanol, ethanol producers will increase their production of ethanol. Generally, increased production of a product leads to a drop in its price.

So the price of ethanol will go down as more of it becomes available.

Studies show that if ethanol production could be three times greater than it is now, the cost of producing a unit of ethanol would drop by forty percent.