Motion-sensing LED lights — these lights are perhaps the most efficient lighting devices available today. They switch on whenever their infra-red sensors detect movement in a room — such as when someone begins to walk down a dark hallway. I’ve been testing them in my own home, and I’ve found them to be effective and non-obtrusive. At night, I’m able to go down two floors to the basement, without turning on any lights. The motion-sensing LEDs in the ceilings switch on as I move about the house.

Untouched natural forests store three times more carbon dioxide than previously estimated and 60 percent more than plantation forests, said a new Australian study of "green carbon" and its role in climate change.