The race is on to build a leaner, meaner and much, much greener car. And now the first team to do it will win up to $25 million.

Corn-based ethanol is an environmentally friendly solution to our reliance on oil, right? Not if it creates food shortages in the world's poorest countries.

For years, I've managed to tune out all things auto. But since I do use a car on a daily basis, I've decided it's time to figure out how to become a better eco-driver.

Wars rage in the Middle East. Gas prices are astronomical. There's a hole in the Alaskan pipeline, and another in the ozone layer. So is now the time to cultivate the youngest generation of SUV-lovers? McDonald's thinks so. Pick up any Hummer Happy Meal and inside you'll find a tiny replica of the gas-guzzling giant.

"This marketing ploy says more about how desperate General Motors has become than anything else," said National Resources Defense Council spokesman Jon Coifman. "Management in Detroit ignored all the signs and bet the farm on big gas guzzlers. Now sales of the huge SUVs and pickups have tanked. Unfortunately, they've taken thousands of good jobs with them."

There's no way around it: Your car is contributing to global warming. In fact, it's almost certainly the single most environmentally harmful component of your lifestyle. The transportation sector is responsible for nearly 40 percent of nationwide greenhouse gas emissions, not to mention plenty of ozone-damaging and smog-forming pollutants. The good news is that new clean-car technologies are emerging at a rapid pace – not just behind the scenes, but in the showrooms of car dealerships near you. Efficient hybrid-engine cars like the Toyota Prius and the Ford Escape SUV can't keep up with demand. Meanwhile General Motors and Ford are ramping up their development of flexible-fuel vehicles that can burn both standard gasoline and biofuels such as ethanol. So if you're in the market for a climate-saving, planet-positive vehicle, which should you choose -- better mileage or biofuel?

It's no secret that Toyota has been trouncing sluggish U.S. automakers in sales growth – thanks largely to its forward-thinking approach to fuel-efficiency. But at the recent L.A. Auto Show