FRED SINGER, George Mason University: I have no doubt that an increase in carbon dioxide in the atmosphere should lead to some increase in global temperatures. The question is, how much? And how can we be sure that any temperature increase that we do find in the record is, in fact, due to this additional carbon dioxide? Since we know that the climate also changes naturally - it warms, it cools - how can you distinguish a warming produced by an increase in carbon dioxide from a warming produced by some other cause, let's say by the sun? NARRATOR: The argument that fossil fuels are changing the climate has alarmed coal, gas and oil producers. Because so much is at stake, the energy industry have been following the scientific arguments closely. FRED PALMER, Western Fuels Assn., Inc: I understand that people get uneasy over the concept of more CO2 going into the air, but you can't live your life based on speculation. And we know today that using fossil fuels is a good thing. It leads to economic growth. It allows more people to live longer on Earth. These are- there are positive goods that come from using fossil fuels. There's a speculative "bad" that people are holding out there, saying, "Therefore. let's stop using fossil fuels." And I think that's an imprudent approach. NARRATOR: The coal industry has mounted an aggressive challenge to the whole idea of human-induced climate change. Its high-powered public relations campaign argues that CO2 has