Light idea now shared by a billion

Ben Cubby March 31, 2012

Earth Hour March 25, 2011. Lights out Sydney Opera House from North Sydney

Lights out ... the Sydney Opera House from North Sydney during Earth Hour last year. Photo: Domino Postiglione

MORE than a billion people will switch off their lights at 8.30 tonight as a symbol of their commitment to tackle human-induced climate change.

Earth Hour, which started in Sydney in 2007, has now spread to 5251 cities and towns in 147 nations and territories, making it the largest voluntary environment movement in history.

Interactive: Earth Hour around the world

The Prime Minister, Julia Gillard, thanked everyone who had pledged to take part, and linked the event to the government's carbon price plan, which comes into force on July 1.

''What began in Sydney as a simple idea to raise awareness of climate change - to switch off the lights for an hour - has become a global success,'' Ms Gillard said in a statement.

The government plans to cut greenhouse gas emissions to 5 per cent below 2000 levels by 2020, with the biggest greenhouse gas emitting companies forced to buy permits to pollute, with much of the proceeds being spent replacing fossil-fuelled power with renewable energy.

A vast array of organisations, communities and businesses have decided to take part in Earth Hour this year.

"Turning off our lights is a symbol of our commitment to sustainable energy for all. We need to fuel our future with clean, efficient and affordable energy,'' said the secretary-general of the United Nations, Ban Ki-moon. The UN headquarters will switch out its lights along with the Opera House and the Harbour Bridge.

Fairfax Media, publisher of the Herald, supports Earth Hour.

Details for all events at @earthhour2012 on Twitter and nsw.gofundraise.com.au

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