General Motors, Ford and DaimlerChrysler cars and light trucks emitted nearly three-fourths of all carbon dioxide from vehicles on US roads in 2004.
Nine other car manufacturers with vehicles on the US market accounted for an additional 84 million metric tons of carbon dioxide emissions, bringing the total for all cars and light trucks in operation in 2004 to 314 million metric tons, the report found.
By comparison, the largest US electric utility, American Electric Power, had emissions of 41 million metric tons.
With just 5 percent of the world’s population, the United States has 30 percent of the world’s automobiles and produces 45 percent of the world’s automotive carbon dioxide emissions, the report said. US cars are driven more and burn more fuel per mile than the international average.