Some observers feel the Soylent Green admission should come as no surprise. "Auto makers have been skirting the regulations for years," says Klaus Brinkbäumer, editor-in-chief of Der Spiegel magazine. "Besides, Volkswagen literally means 'People's Car.' So..." he said with a shrug.

Earlier last week, the Obama administration unveiled a blueprint for cutting greenhouse gas emissions in the United States by up to 28 percent over the next decade and submitted the formal statement to the to the United Nations Framework Convention on Climate Change.

In the 1920s the US was the largest user of electric cars in the world, and they outsold gasoline-powered cars

In transportation, as in so many economic sectors, the needs of the planet and the demands of capitalism are pulling in the same direction. An investment in fast-growing clean transportation technology is an attractive business proposition.

The ads tell consumers only part of the gas mileage story, sowing confusion about which cars are clean and which are not -- and leaving buyers at risk of driving off in vehicles that get worse mileage than they expected.