AS SYDNEY plunged into darkness last night, billions saw the light around the world. From Mumbai to Berlin, landmarks blended with the night sky, while friends and neighbours broke bread - and records.
Thousands of cities in more than 130 countries took part.
Sydney reduced its energy usage in the city centre by 12 per cent - equivalent to switching off 2 million energy-saving bulbs for an hour, electricity retailer Ausgrid said. It was the best result since Earth Hour was launched in 2007.
For the first time a community in Swaziland was involved, thanks to the efforts of a 15-year-old, Nathi Mzileni, who attracted support from media and sponsors to launch the event in his village.
Five years after its inception, Earth Hour has a new message: it is not just about switching off the lights for 60 minutes but creating a long-term sustainable future for the planet. This is the key focus of Earth Hour 2011, a campaign that has been embraced in record numbers since it first took place in Sydney.
Dermot O'Gorman, chief executive of the World Wildlife Fund Australia - which organises the event with Fairfax Media, publisher of The Sun-Herald - said it was proof that small actions could inspire global change.
''Earth Hour has evolved so much over the past five years,'' Mr O'Gorman said. ''It's gone from a small idea to something which is now embraced by 131 countries and hundreds of billions of people.''
However, critics of Earth Hour suggest switching off the lights is tokenistic, incapable of effecting lasting, permeable change. Mr O'Gorman argues that for many participants Earth Hour is the catalyst for greater change. He said turning off the switches for an hour was part of a bigger movement.
''It's not just about doing something for one hour; it's about doing something every day that can lead to a more sustainable future,'' he said. ''We really want people to consider long-term action for sustainability.''
Andy Ridley, joint founder and executive director of Earth Hour, urged Australians to extend their commitment to the environment.
''Earth Hour is a chance for people and communities across the globe to join together with the common purpose of a sustainable future for our planet," Mr Ridley said. "This year Earth Hour asks people to commit to an action, big or small, for the coming year, taking Earth Hour beyond the hour."
For the first time, Australians with the most inspiring ideas for long-term sustainable living have been recognised through the inaugural Earth Hour Awards, held last night at the Museum of Contemporary Art.
Hosted by television personality Jamie Durie, the awards comprised five categories and a people's choice award. Sydney students Hanan Hassan and Julia Lin won the Young Panda Award for running an environmental awareness group at their primary school, while the Workplace Champion Award was shared by Benjamin Grimshaw of the Sydney Hilton and Sarah Mandelson of Serendipity Ice Cream in Marrickville.
Mr O'Gorman said the winners, chosen from 130 entrants, were a testament to Australian ingenuity.
"These people demonstrate how we can rally our communities to support the environment," he said.
Durie said he was ''pretty proud'' of what the cause had achieved.
''I've been involved with the World Wildlife Fund for a couple of years now,'' he said. ''This is definitely the most influential environmental event that has come out of Australia, if not the world, for the last decade.
''This reaches 4000 cities and over 131 countries and they've done all this in just five years.''
Last night Sydney residents marked the occasion with a number of community events.
The largest public event was held at First Fleet Park near Circular Quay, where guests ate snacks made from locally produced and sustainable ingredients as they watched icons such as the Opera House, the Harbour Bridge and Luna Park disappear into darkness. Across Australia about 10 million people took part in Earth Hour, as well as thousands of businesses that agreed to turn out the lights.
At the Shangri-La Hotel at The Rocks in Sydney, chefs cooked by candlelight as customers at a sell-out dinner at Altitude restaurant gazed on the spectacle from the 36th floor.
Other countries that took part in Earth Hour for the first time included Jamaica, Iran, Uganda, Tajikistan, Chad, Azerbaijan, Gibraltar, Suriname, Uzbekistan, Trinidad and Tobago, and Lesotho.