Some see the fossil fuel known as coal as the answer to our prayers for abundant energy. It all depends on our willingness to extract the carbon dioxide out of coal before we burn it -- and to put up with the ravaging of the countryside to dig it up -- including massive erosion and water pollution. Coal mining makes some places look lunar.

Carbon dioxide is the greenhouse gas most responsible for climate warming. Gasoline made from coal produces far more carbon dioxide than does fuel made from oil or natural gas. So any ramp-up in the use of coal-based fuels, without capturing the greenhouse gases, would accelerate climate change.

The coal in Illinois alone could make more energy than all the oil in Saudi Arabia. And the technology to turn coal into gasoline is well tested. The Germans used it extensively during World War II. And the technology to control emissions of the traditional pollutants from coal-burning electricity plants -- such as nitrogen oxides and sulfur dioxide, which cause acid rain -- is readily available.

What is still needed is a way to remove carbon dioxide, the greenhouse gas, in large quantities.

Wallace Broecker, a climatologist at Columbia University's Lamont-Doherty Earth Observatory, says that pulling out the carbon dioxide is not difficult. It's already done in submarines and space shuttles. The tough part is doing it on a gigantic scale, which would be necessary if coal were to be turned into motor fuel in large quantities.

Mr. Broecker asserts that doing this would come at a cost, but a manageable one. He says that gasoline can now be produced from coal for from $40 to $45 a barrel. The cost of capturing and storing the carbon dioxide would raise its price by 20 to 30 percent. But with oil recently at over $75 a barrel, the gasoline produced from coal could be economically competitive.

A plant in East Dubuque, Ill., run by Renentech, makes diesel fuel out of coal but does not extract the carbon dioxide. That's not good. This kind of plant is a "step backward," Princeton researcher Robert Williams told The New York Times. "It almost doubles the emission rate [of greenhouse gases]."

Unfortunately, a favored way to make diesel from coal -- the Fischer-Tropsch technology -- is environmentally deadly. Alas, Energy Secretary Samuel Bodman said recently that loan guarantees in last year's energy bill might be applied to making Fischer-Tropsch diesel fuel.

Meanwhile, Gary Comer, the founder of the Lands' End mail-order house, is funding a project to build a prototype machine to remove carbon dioxide and perhaps store it underground.

Carbon dioxide is one issue. But then consider what you have to do to get the coal out of the ground -- create wastelands. All in all, basing our energy hopes on coal seems unwise.