The idea is for us all to switch off our lights for an hour - at 8.30pm local time - to hightlight the issue of global warming.

So far, more than one thousand, one hundred cities, towns and countries have signed up for the event - the biggest contingent since earth hour began in Sydney 2 years ago.

The idea is for us all to celebrate something we have in common - the place we live, planet Earth and to raise awareness about how our consumption of energy is impacting on our environment.

Here in Adelaide, our popular "East End" will be plunged into darkness, and the power to other city landmarks will also be turned off.

In Melbourne, a pedal powered concert will be held at Federation Square.

Cynics of the idea would say Earth Hour is simply a token gesture that won't do anything to lessen the impact on of climate change.

There's an argument that no matter what we do here in Australia, emerging powers such as China and India are still going to pump huge amounts of Co2 into the atmosphere.

Latest figures suggest that China is the largest consumer of coal in the world - getting a massive 69 percent of its energy needs from coal fired power stations and that's likely to continue to climb.

And, let's not forget the United States; currently 49 percent of its energy comes from burning coal.

At the moment India accounts for just 4 percent of the world's energy consumption but it continues to grow at the rapid rate of 3.6 percent a year.

Added to that CSIRO scientists have just discovered that two new greenhouse gases growing in our atmosphere, which "have significant global warming potential".

The gases are used in industrial processes - in the electronics industry and in fumigation.

These gases have become more widely used as alternatives to other greenhouses gasses - but their impact appears to be just as devastating.

So, one has to ask the question: what good is it really going to do, if just some of us just turn off our power for just one hour?

Well, I guess it goes back to the notion of individual action having some small impact. If enough of us change then major transformation is possible - it's the belief that if we all change a little, then the world can change a lot.

So, perhaps the power of Earth Hour is the positive message it sends, the awareness it creates and the feeling of solidarity between those who inhabit this wonderful planet.

I, for one intend to turn off my lights for an hour ... I do believe in the power of the individual and besides, any excuse for a candle-lit dinner is fine by me.