How Australia became the dirtiest polluter in the developed world.
Luxury electric-car maker Tesla is getting a $34.7 billion tax break from California.
The once inexperienced businessman is changing the face of solar energy.
As green as a golf cart? A Prius? An SUV?
A new report says New York City could slash its emissions by a whopping 90 percent by 2050 simply by making its buildings more energy efficient.