When the third rock from the sun switches off its lights between 8.30 and 9.30 Saturday night, you know something is on.

The hugely popular and symbolic campaign against climate change has corporations, public bodies and individuals, raring to jump on to the “green bandwagon” to pledge support for action against climate change.

Come March 27, lights will be dimmed in 56 cities across the country. In no mood to be left behind, Bangalore Electricity Supply Company Limited (BESCOM) has written to no less than 250 welfare associations and corporations to go dark from 8.30 p.m. to 9.30 p.m. Public buildings such as the power-hungry Vidhana Soudha or Town Hall, large IT offices and parks — where power consumption is anyway low on Saturday evenings — and hotels have pledged to support the cause.

Last year, BESCOM recorded a drop of 80 MegaWatt peak load (against a daily average of 1,800 MW) on the occasion, a senior official said. BESCOM aims to save at least 0.8 million units on Saturday, compared to an average daily consumption of 33 million units.

This idea, born in Sydney in 2007, has since turned global. Mobilised and branded by the World Wide Fund for Nature (WWF), this year's Earth Hour has reputedly spread its wings wider with 120 countries signing up so far, compared to 88 last year. This promises to be the biggest mass event aimed at “speaking up against climate change”, WWF says. But, ask the detractors, “Why choose Saturday?” While corporates claim credit for pledging allegiance to the cause, one may wonder the sincerity of an attempt to “minimise resources” on a day when offices are shut.

A few companies, Infosys Technologies for one, have taken it beyond the token one hour by organising weeklong activities such as Earth Habba or green campaigns to build awareness. However, it must be noted that companies that provide round-the-week customer service, for clients at home and abroad, can hardly afford to join the initiative. A spokesperson of an IT major told The Hindu that it is only the R&D wing that will observe Earth Hour, while the BPO and client servicing sections cannot afford a break.

The 1,300 fans of the Facebook group Anti-Climate Change, a pittance compared to the fans that the WWF Earth Hour page has (2,18,880), maintain that this initiative is a sham. Critics point out that the carbon credits gained in the 60-minute token blackout barely makes up for the energy used to back this campaign, both online and offline.

Elaborate symbolism or not, Earth Hour has familiarised many with the critical issue of climate change.

At the end of the day, whether participants in this global campaign will return at 9.30 p.m. to their usual appetite for power or not will be an individual decision.