A lightning show was the brightest part of Sydney's skyline during Earth Hour, which began at 8 p.m. when the lights were turned off at the city's landmarks. Most businesses and homes were already dark as Sydney residents embraced their second annual Earth Hour with candlelight dinners, beach bonfires and even a green-powered outdoor movie.
"This provides an extraordinary symbol and an indication that we can be part of the solution" to global warming, Australian Environment Minister Peter Garrett told Sky News television, standing across the harbor from the dark silhouette of the Opera House.
Garrett said government offices and national monuments around the country participated in Earth Hour.
"We're not only talking the talk, we're walking the walk," he said as the hour ended. "Whatever your view is about the magnitude of the problem ... we can save money by using energy wisely and efficiently, and that gives us the added bonus of reduced greenhouse gas emissions."
During the one-hour event, Sydney was noticeably darker, though it was not a complete blackout. The business district was mostly dark; organizers said 250 of the 350 commercial buildings there had pledged to shut off their lights completely, and 94 of the top 100 companies on the Australian stock exchange were also participating.
The number of participants was not immediately available but organizers were hoping to beat last year's debut, when 2.2 million people and more than 2,000 businesses shut off lights and appliances, resulting in a 10.2 percent reduction in carbon emissions during that hour.
"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.
The effect of last year's Earth Hour was infectious. This year 26 major world cities and more than 300 other cities and towns have signed up to participate.
New Zealand and Fiji kicked off the event this year. In Christchurch, New Zealand, more than 100 businesses and thousands of homes were plunged into darkness, computers and televisions were switched off and dinners delayed for the hour from 8 to 9 p.m. Suva, Fiji, in the same time zone, also turned off its lights.
Auckland's Langham Hotel switched from electric lights to candles as it joined the effort to reduce the use of electricity, which when generated creates greenhouse gases that contribute to global warming.