Green Hands USA: America Volunteers

This Saturday night, people around the world will turn off their lights for one hour to show their support in the fight against climate change.

It's all part of Earth Hour, an annual even that takes place this year on March 31 and encourages people, businesses and government agencies to turn off every light in their homes and offices from 8:30-9:30 pm (local time) as a sign that they are serious about reducing energy use and fighting climate change.

Earth Hour has grown from a one-city initiative in 2007 to a worldwide even that last year reached 1.8 billion people in 135 countries across all seven continents.

“In its sixth year, with hundreds of millions of people taking part in Earth Hour, we want to go beyond the hour to encourage positive action for the environment,” said Earth Hour Co-Founder and Executive Director, Andy Ridley.

This year, Earth Hour has added a new "I Will If You Will" campaign (youtube.com/earthhour), which encouragespeople to share a personal dare with the world, by asking "What are you willing to do to save the planet?" A wide range of celebrities, politicians and eco-minded individuals have already uploaded their personal challenges.

So show your support this year. Sign up, then turn those lights off for an hour and then see what you can do to keep the Earth Hour spirit going the rest of the year.