SYDNEY—Earth Hour returned to Australia on Saturday night, with Sydney's postcard-perfect harbour again temporarily plunged into darkness.
At 8pm (AEDT), the harbour bridge and its neighbouring Opera House dimmed from flood-lit tourism icons to still recognisable silhouettes.
Only security lighting remained on the structures, while elsewhere in Sydney's CBD, the office towers glowed rather than blazed against the night.
As lines of office lights inked out, a crowd of about 100 people at the harbourside park of Mrs Macquarie's Chair cheered.
"Earth Hour is a call to action. People have now responded and it's time to introduce some significant long-term changes," Sydney Lord Mayor Clover Moore said at an official Earth Hour function at the park.
"One inspired idea that began in Sydney just 12 months ago has become a world movement," she said.
Federal Climate Change Minister Penny Wong also addressed the function, saying the first significant act of the Rudd Government was to sign the Kyoto Protocol.
"Earth Hour is a way in which individuals can take responsibility when it comes to climate change," she said.
When the first Earth Hour was staged in Sydney a year ago, an estimated 2.2 million Sydneysiders took part.
Organisers are tipping a massive increase in participation as the event has gone global this year.
"I'm putting my neck on the line but my hope is that we top 100 million people," Earth Hour Australia Chief Executive Greg Bourne said.
"There's 370 cities and municipalities taking part that we know about, and many others as well, so we only need 50 cities of two million people and we'll do it.
"When Canada goes ... tomorrow our time they are estimating some 70 per cent of Canadians will be involved."
Mr Bourne said Earth Hour, and its images of blacked-out cities, was akin to New Year's Eve as it was celebrated in the world's major cities with fireworks.
"Now we have this image of darkness, and consciousness, going around the world," he said.
"It is a message of hope and optimism ... we the citizens of the world are prepared to take action and we want to defeat climate change."
The world's differing time zones has required a staggered observance of Earth Hour, and Australia was one of the first to mark the climate change awareness event.
Only Christchurch in New Zealand and Fiji's Suva were ahead of Australia as the hour of 8pm, on March 29, rolled around.
More than 30 nations are to follow.
The US cities of San Francisco, Phoenix and Canada's Vancouver will be the final population centres to mark Earth Hour, at 2pm on Sunday Australia-time.
The only exception to timezone order was Israel's Tel Aviv, where Earth Hour was brought forward to 8pm, March 27, for religious reasons.
The core message of Earth Hour is for people to reduce their consumption of electricity, which is usually generated by the burning of fossil fuels.
Elsewhere in Australia, Melbourne icons including Flinders Street Station, Federation Square, Eureka Towers Skydeck and the Rialto Towers were blacked out tonight.
The Criterion Hotel in the north-central Victorian town of Tatura planned to host a pyjama party, with a free beer on offer for those who bring a black balloon along - a symbol of an individual's carbon footprint.
"Pubs do tend to use a fair bit of power and energy," said the pub's licensee Nick Matei.
"We just want to make people more aware, and this is a good point to start."
In Canberra, it was security lighting only in prominent buildings including the High Court of Australia, the National Library of Australia, the Australian War Memorial, and Parliament House.
"Even with a function scheduled on the night, the National Gallery of Australia has signed up to switch off as many lights as possible, to conserve energy for the benefit of our environment," Penny Wong said in a statement.
Brisbane's First Earth Hour Hailed a Success
BRISBANE—Brisbane's Story Bridge, City Hall, and the iconic Castlemaine Perkins XXXX brewery were blacked out last night, as the city took part in its first Earth Hour.
The Queensland capital joined 369 cities in 35 countries for the World Wildlife Fund (WWF) initiative to raise awareness of climate change.
Earth Hour, which started in Sydney last year, encouraged people to switch off their lights between 8pm and 9pm yesterday, and in doing so, consider their energy use long into the future.
Crowds gathered at South Bank, on the Brisbane River, at Kangaroo Point, and atop Mt Coot-tha to view the spectacle.
Candlelit dinners and dating events were held at restaurants and hotels around the city.
WWF climate change policy manager Kellie Caught, who viewed the event from Kangaroo Point, said she was heartened by the response from Queenslanders.
"Looking up at the apartments, at the apartments at South Bank ... you could see lights off and candles lit, which was really lovely to see," Ms Caught said.
"We are really encouraged, it gives us hope that people do care about the environment and climate change, and it sends a strong message to government that business and people do want action on climate change."
Statistics on the number of people who took part in Earth Hour worldwide will be released later today.
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