While some politicians and environmentalists believe that "biofuels" like corn ethanol could lower America's dependence on foreign oil, others argue that ethanol actually costs energy to produce and has disastrous effects on food production.

As Iowa farmers use more land for corn and less for other crops like soybeans, the prices for those crops increase around the world. To meet the growing demand, other countries cut down their own forests to plant soybeans, releasing carbon dioxide into the air and potentially harming the environment.

Heidi Cullen, from the scientific research group, Climate Change, talks to Iowa farmers and scientists about the controversy surrounding ethanol and climate change.

"Our economy is in its deepest recession since the 1930s, and our national security is endangered by a vicious terrorist network and the complex challenge of ending the war in Iraq honorably, while winning the military and political struggle in Afghanistan. As we search for solutions to all three of these challenges, it is becoming ever clearer that they are linked by a common thread: our dangerous over-reliance on carbon-based fuels." Al Gore, former Vice President

"Farming's like going to Las Vegas and -- and rolling the dice and losing it on the tables or playing blackjack, except it takes nine months to lose it. So the house always wins, yes." Craig Griffieon, Iowa farmer

"You know, ethanol production in the state of Iowa has really helped out our corn prices. It's taken a lot of the excess corn that we did have in the state and we've moved it into the biofuel area. Ethanol production has created a lot of jobs." Dennis Bogaards, Iowa farmer.

"Exactly how much control do we have over what Brazil, a sovereign nation, is doing with their tropical land use? We have no control. So why should our biofuels policy be subject to things over which we have no control?" David Miller, Iowa Farm Bureau

1. What are some alternative sources of energy to gasoline and oil?

2. What is "ethanol"?

1. Is climate change an important issue to you? Why or why not?

2. Do you think ethanol is an answer to the problem of America relying on foreign oil? Why or why not?

3. In these difficult economic times, Iowa farmers are making money from producing more corn for ethanol. How should they balance the need to make a living with the affects on forests and land around the world?

4. If you were the president, which alternative forms of energy would you focus on?