Lights out for Earth Hour 2009

“Turn on, tune in, drop out,” the LSD-munching pop psychologist Timothy Leary once advised.

But “sign up, switch off, shut down” will be a more appropriate mantra tonight as cities across the globe turn out their lights as part of WWF’s Earth Hour.

Lights out: The Coca Cola strip in Piccadilly Circus will be switched off for only the third time in over 60 years

Sydney Opera House, the Eiffel Tower, Nelson’s Column and the London Eye are among 280 iconic landmarks which have agreed to go fluorescent-free from 8.30pm GMT in support of affirmative action on climate change.

The Coca Cola sign in Piccadilly Circus will be turned off for only the third time since the Second World War.

Earth Hour began in Sydney in 2007 and resulted in a 10 per cent reduction on the electrical grid, saving 25,000 tonnes of carbon dioxide. Since then it has grown into global event, a unique opportunity for people from Las Vegas to Istanbul to vote with their light switch for decisive measures to combat global warming.

It has been criticised by some as a tokenistic gesture offering councils and corporations an easy chance to hop on the eco-band wagon (exactly how much energy does the Piccadilly Circus Coca Cola sign burn up in the other 8,759 hours of the year?)

But the aim is not so much the amount of carbon emissions which can be saved in one hour, but the show of support it signifies for a more proactive and comprehensive attitude towards tackling climate change across the globe.

So far 1180 cities have signed up to switch off for Earth Hour, and WWF are hoping for one billion people to show their support.

Will you be one of them?