By Jane Garcia

Thirteen cities worldwide have signed up to participate in Earth Hour 2008, when residents will be asked to turn off their lights for 60 minutes at 8pm on Saturday March 2009 next year.

The inaugural Earth Hour was held in Sydney last year. About 2.2 million Sydneysiders participated and they saved the equivalent amount of carbon dioxide emissions as removing 48,000 cars off the road.

Speaking at the Earth Hour launch today (December 14), Sydney Lord Mayor Clover Moore said the Earth Hour blueprint was now available to all cities, towns and villages around the world.

Cities already committed to participating in the 2008 event include Sydney, Canberra, Melbourne, Brisbane, Toronto (Canada), Chicago (USA), Copenhagen (Denmark) and Tel Aviv (Israel).

WWF Australia CEO Greg Bourne said about 12 to 14 million people were covered in the first set of participating cities, although he extended the invitation to participate in the event to cities and towns of any size.

"It really just requires the citizens of the city to come together and act," he said.

For more see www.earthhour.org