By Paul Bedard, Washington Whispers A noted geologist who coauthored the New York Times bestseller Sugar Busters has turned his attention to convincing Congress that carbon dioxide emissions are good for the Earth and don't cause global warming. Leighton Steward is on Capitol Hill this week armed with studies and his book Fire, Ice and Paradise in a bid to show senators working on the energy bill that the carbon dioxide cap-and-trade scheme could actually hurt the environment by reducing CO2 levels. "I'm trying to kill the whole thing," he says. "We are tilting at windmills." He is meeting with several GOP lawmakers and has plans to meet with some Democrats later this week. Much of the global warming debate has focused on reducing CO2 emissions because it is thought that the greenhouse gas produced mostly from fossil fuels is warming the planet. But Steward, who once believed CO2 caused global warming, is trying to fight that with a mountain of studies and scientific evidence that suggest CO2 is not the cause for warming. What's more, he says CO2 levels are so low that more, not less, is needed to sustain and expand plant growth. Trying to debunk theories that higher CO2 levels cause warming, he cites studies that show CO2 levels following temperature spikes, prompting him to back other scientists who say that global warming is caused by solar activity. In taking on lawmakers pushing for a cap-and-trade plan to deal with emissions, Steward tells Whispers that he's worried that the legislation will result in huge and unneeded taxes. Worse, if CO2 levels are cut, he warns, food production will slow because plants grown at higher CO2 levels make larger fruit and vegetables and also use less water. He also said that higher CO2 levels are not harmful to humans. As an example, he said that Earth's atmosphere currently has about 338 parts per million of CO2 and that in Navy subs, the danger level for carbon dioxide isn't reached until the air has 8,000 parts per million of CO2. Steward is part of a nonprofit group called Plants Need CO2 that is funding pro-CO2 ads in two states represented by two key lawmakers involved in the energy debate: Montana's Sen. Max Baucus and New Mexico's Sen. Jeff Bingaman.