WASHINGTON (AP) - As the United States struggles with its embarrassing title as the world's leader in greenhouse gases, it must be noted that some states spew far more than their share and show no signs of slowing down. -Wyoming's coal-fired power plants produce more carbon dioxide in just eight hours than the power generators of more populous Vermont do in a year. -Texas, the leader in emitting this greenhouse gas, cranks out more than the next two biggest producers combined, California and Pennsylvania, which together have twice the population of Texas. -In Alaska, the carbon dioxide produced per person by all the flying and driving necessary to get around the large but sparsely populated state is six times the per capita amount generated by travellers in New York state. In their daily lives, many people in the U.S. unwittingly contribute far more to global warming than their neighbours purely because of where they live. A review of state-by-state emissions of carbon dioxide from 2003, the latest numbers available, shows startling differences in states' contribution to climate change based on their reliance on burning high-carbon coal for cheap electricity. "There's no question that some states have made choices to be greener than others," said former top Energy Department official Joseph Romm, author of the new book "Hell and High Water" and executive director of a nonprofit energy conservation group. The disparity in carbon dioxide emissions is one of the reasons there is no strong national effort to reduce global warming gases, some experts say. "Some states are benefiting from both cheap electricity while polluting the planet and make all the rest of us suffer the consequences of global warming," said Frank O'Donnell, director of the Washington environmental group Clean Air Watch. "I don't think that's fair at all." He noted that the states putting out the most carbon dioxide are doing the least to control it, except for California. Several federal and state officials say it's unfair to examine individual states' contribution to what is a global problem. "If the atmosphere could talk it wouldn't say, 'Kudos to California, not so good to Wyoming'," said assistant energy secretary Alexander Karsner. "It would say, 'Stop sending me emissions.' " Some coal-burning states note that they are providing electricity to customers beyond their borders, including Californians. Wyoming is the largest exporter of energy to other states, says Gov. Dave Freudenthal. He said two-thirds of the state's carbon footprint "is a consequence of energy that is developed to feed the rest of the national economy. That doesn't mean that somehow then it's good carbon, I'm just saying that's why those numbers come out the way (they) are," Freudenthal said. And the massive carbon dioxide-spewing and power-gobbling refineries of Texas and Louisiana fuel an oil-hungry country, whose residents whine when gasoline prices rise. However, some of the disparities are stunning. On a per-person basis, Wyoming spews more carbon dioxide than any other state or any other country: more than 125,000 kilograms of it per capita a year, thanks to burning coal, which provides nearly all of the state's electrical power. Just next door, Idaho emits the least carbon dioxide per person, less than 10,500 kilograms a year. Idaho relies mostly on hydroelectric power. Texas, where coal barely edges out cleaner natural gas as the top power source, belches more than 544 million kilograms of carbon dioxide yearly. That's more than every country in the world except six: the United States, China, Russia, Japan, India and Germany. North Dakota's power plants crank out 68 per cent more carbon dioxide than New Jersey, which has- times North Dakota's residents. And while Californians have cut their per-person carbon dioxide emissions by 11 per cent from'90 to 2003, Nebraskans have increased their per capita emissions by 16 per cent over the same time frame. Officials in Wyoming, North Dakota and Alaska say numbers in their states are skewed because of their small populations. But Vermont, Rhode Island and the District of Columbia are similar in size and have one-12th the per-capita emissions of Wyoming. A lot of the discrepancy comes down to coal. Burning coal accounts for half of the electricity produced in the U.S., and produces more carbon dioxide than any other commonly used fuel source. The states that rely the most on coal - Wyoming, North Dakota, West Virginia, Indiana - generally produce the most carbon dioxide pollution per person, but also have the cheapest electric rates. States that shun coal in favour of nuclear, hydroelectric and natural gas, produce less carbon dioxide but charge more for power. It's unfair to pin all the blame on the coal-using states, said Washington lawyer Jeffrey Holmstead, who represents coal-intensive utilities and refineries. Holmstead, as the former air pollution regulator in the Bush administration, ruled that carbon dioxide was not a pollutant, a decision that has been overturned. He argues that outlawing coal-fired generating plants would have little overall impact globally. Texas government officials seemed to be following that line of thinking when they encouraged the state's biggest utility, TXU Corp., to plan for 11 new coal-burning power plants. The strategy collapsed when an investor group buying TXU cut a deal with environmentalists to drop plans to build most of the coal plants. The Texas state agency charged with monitoring the environment declined to comment on carbon dioxide emissions. Spokeswoman Andrea Morrow said the gas "is not a regulated pollutant." Emissions from generating electricity account for the largest chunk of U.S. greenhouse gases, nearly 40 per cent. Transportation emissions are close behind, contributing about one-third of U.S. production of carbon dioxide. States and cities with mass transit come out cleaner than those with wide expanses that rely solely on cars, trucks and airplanes, like Alaska. Alaska, which stands out for its carbon dioxide production, also stands out as one of the early victims of climate change. Its glaciers are melting, its permafrost thawing, and coastal and island villages will soon be swallowed by the sea. Alaska ranked No. 1 in per-person emissions for transportation, which includes driving, flying, shipping and rail traffic. That's not the state's fault, says Tom Chapple, director of the state Division of Air Quality. Its sheer expanse requires a lot of air travel. And Anchorage ranked No. 2 nationally in air cargo traffic. For people who want to reduce their household emissions, or their "carbon footprint," the state where they live really does matter. After seeing Al Gore's documentary, "An Inconvenient Truth," Gregg Cawley used one of the many calculators available online to determine his "carbon footprint." The University of Wyoming professor lives in a small one-bedroom apartment and drives a moderately efficient Subaru, so he figured he contributes less to global warming than the average American. But the calculations suggested Cawley produces more carbon dioxide than most Americans. Even if he reduced his energy consumption, the numbers would hardly budge. "My God," he thought, "what do I have to do to my lifestyle to change this?" Then he changed his home state in the equation. He took out Wyoming and plugged in Washington state. "I came in way low. I said, 'That's the problem. I live in the wrong damn state.' " - Associated Press writers Bob Moen in Cheyenne, Wyo.; Paul J. Weber in Dallas; Dan Joling in Anchorage, Alaska; Terence Chea in San Francisco; and Mike Hill in Albany, N.Y., contributed to this report.