Clearing up the ever returning myth on the hybrid vehicle; doesn't manufacturing of a hybrid vehicle create (a lot) more CO2 than the amount you can save with the increased efficiency?
Short answer: no, a Prius battery would have to weigh about 10 tons before a conventional Hummer would be cleaner. For a more detailed answer, check out the referenced article below.
I'm quite surprised, not by this answer, but as to why these stories go around. Is it part of some parties who are not in favour of the hybrid vehicle? All the more reason to be a bit critical when reading something and add a little research in it for yourself.
Green Guru: Emissions from Building Hybrid Cars | Audubon Magazine ...
Only 13 percent to 28 percent of total lifecycle emissions occur during production, whether the vehicle is a conventional car or a hybrid, Constantine Samaras and colleagues at the nonprofit RAND Corporation found. “While batteries are energy-intensive, they still comprise just a small amount of the greenhouse-gas footprint from [hybrid] vehicles,” he says.