Sydney: Millions of people from Sydney to Sweden are set to switch off their lights on March 27, as part of the global `Earth Hour` campaign to highlight climate change, organisers said Sunday.
Some 250 cities around the world have already signed up for the symbolic, energy saving exercise which in 2009 saw landmarks such as the Sydney Harbour Bridge and New York`s Empire State Building plunged into darkness.
"The event will be held at 8:30 pm Saturday 27 March in cities and towns all over the world," conservation group WWF-Australia`s Chief Executive Officer Greg Bourne said.
Earth Hour began in Sydney in 2007 when 2.2 million people switched off the lights in their homes, offices and businesses for 60 minutes to make a point about electricity consumption and carbon pollution.
The campaign went global the following year and by 2009 some 3,929 cities, villages and localities across the globe elected to cut their lights in aid of the environment.
Organisers said numerous cities and towns in Australia would be joined by many in Canada, the United States, Singapore, Russia, Sweden, Belgium, Bolivia, South Korea, New Zealand, Switzerland and Turkey for the 2010 event.
Moscow, Rio de Janeiro, Rome, Seoul, Manila, Singapore, Toronto, Hong Kong and Dallas are the latest to confirm their commitment but more cities are expected to join the campaign closer to the date, a spokeswoman said.
In its fourth year, Earth Hour is asking participants to do something more than the one hour of darkness -- which reduces the amount of fossil fuels burned to create electricity -- and think about their total carbon footprint.
"We`re asking people to go beyond turning off lights and instead make an Earth Hour resolution to start something bigger," said Bourne.
"Switching off your lights is a great first step, but your true environmental impact is much bigger than just your energy bill."
Scientists have warned that global warming caused by burning fossil fuels on a massive scale could devastate the planet, hitting the poorest countries hardest with floods, droughts and disease.