This weekend will see the largest participation in Earth Hour yet. Over 4500 cities, from over 131 countries in each continent of the globe will take part. For one hour, 8.30pm on Saturday 26 march, they will turn off all non-essential lights and power. For 60 minutes, they will muse and reflect in the darkness on their reliance on carbon fuel and the need for sacrifice if climate change is to be effectively tackled.
It is symbolic, organisers form the WWF (World Wildlife Fund) say, it shows a public commitment to the desire for change, if nothing else.
Yet the annual event that began in 2007, might be facing a ticking clock. Criticism is growing. There are allegations of ''tokenism'' and that it is an ineffectual response. A darling of large corporations who want to align themselves with a brand to increase their green credibility might be, in themselves damaging what began as an underground zeitgeist.
In Australia, the Carbon Sense Coalition argues the media and green campaigners vilify carbon dioxide too severely. They claim Earth Hour actually emits more carbon dioxide because of the propensity of champagne and candle parties, as people celebrate their environmentally friendly actions. In addition, they say holding Earth Hour in a month that's warm across much of the globe hardly has as much of an impact if it were held in say, the depth of winter, or the rainy season.
A post on their website reads, ''Let the true believers try the real thing in one of the extreme seasons so they can appreciate the great benefits we take for granted when using all our carbon fuel and foods''.
In response, Earth Hour has decided to go one step further. Rather than simply represent an hour's activity, the WWF wants to develop a legacy. Hence Beyond The Hour. Beyond The Hour asks visitors to its website to ''take action to make our world a better place.'' People are asked to post resolutions, promises they will undertake to continue their commitment to tackling climate change, be it shopping locally, or turning off the TV at night rather than leaving it on standby.
Linked with a wide-reaching social media campaign, organisers hope this year the event will reach more people than ever, and convince each of them to take action to tackle climate change.
Earth Hour is held 8.30pm Saturday 26 March. Visit www.beyondthehour.org for more details.