Along with emissions from power plants, pollution from vehicles is the major air-pollution culprit. But that could change if cars ran on sugar, as a team of scientists at the University of Wisconsin at Madison has proposed. In a paper published in yesterday’s edition of the journal Nature, the scientists detailed a technique for breaking down a glucose solution into hydrogen and carbon dioxide. The hydrogen would then be pumped into a fuel cell that would power a car or truck, and the carbon dioxide would be released into the atmosphere. That might sound like a recipe for more global warming, but the scientists say the process does not produce any more CO2 than would be released into the air as the sugar sources biodegraded naturally. The process is still in the early research stages, but its implications are potentially huge as the automotive industry seeks out clean, renewable energy sources.