General Motors plans to introduce a new hybrid model every three months for the next four years and says the auto industry is entering an era where it will "shift significantly to a different model of propulsion" because reliance on petroleum "is not going to work"

That's an aggressive timeline and bold statement from Chairman and CEO Rick Wagoner Jr., and it offers some of the most compelling evidence yet that GM is serious about recasting itself as an environmentally conscious company while reinventing the auto industry.