Earth may look a little darker from space this March 29, with as many as 30 million people in various parts of the world set to turn off their lights and televisions. So far 24 cities have signed up to be part of Earth Hour which was organized to raise awareness about the topic of climate change.

Last year 2.2 million people in Sydney, Australia participated in the event and this year that number is expected to increase dramatically as cities such as Vancouver, San Francisco, Bangkok and Atlanta take part.

"If we see the same participation levels around the globe that we did in Sydney, then we can anticipate more than 30 million people involved," said Andy Ridley, Earth Hour's executive director. "Climate change is a truly global issue and people around the world are demanding action," he said.

Participants are asked to switch off lights and any non-essential electrical devices at 8 p.m. and leave them off for one hour. The Golden Gate Bridge in San Francisco, as well as the CN Tower in Toronto are among the high-profile buildings scheduled to plunge into darkness for the event.

It's no huge secret that we waste a lot of energy thanks to electrical devices. While I don't think I'll be making a habit of making my around my home by candlelight every single night, this may serve as a demonstration of just how much unneccessary energy we expend through carelessness or sheer laziness. Maybe participants (myself included) will start to think twice about simple acts like shutting off a light when we leave an empty room.

» Reuters Environment