Cooling down the world's cities, one rooftop at a time.

Colorado is about to let residents collect rainwater, but the debate is far from over.

Market trends and new regulations spell the end for one of America's dominant sources of energy.

The historic climate agreement struck in December has yet to be signed, and already has suffered one setback after another.

After the Democratic candidates depart, the city may be on its own again.

A new report shows that the leak in California was nothing less than devastating.