Millions of people worldwide have been switching off lights for an hour at 8.30pm local time today, in what is described as the biggest climate change protest ever attempted.

From 8.30 to 9.30 pm on Saturday 28 March 2009, around a billion people will switch off their lights in an effort to convince the world’s leaders to get serious about climate change.

A Catholic cathedral is taking a lead in the campaign against climate change, and encouraging others to follow suit, by turning off its lights to mark Earth Hour.

Could you live without electricity for an hour? On 31st March 2007 2.2 million homes and businesses in Sydney proved that this is possible when they turned off their lights in a city-wide demonstration against climate change. This unusual event generated so much interest that just a year later the WWF initiative went international.