Earth Hour, a global environmental movement to check global warming and preserve energy from participation of individuals and organisations has spread to at least 50 countries.

Andy Ridley, Chief Executive said on Wednesday that the “I Will If You Will” campaign, launched in 2012 in 13 countries, is expected to expand its geographic reach almost fourfold this year, strengthening the group’s impact beyond an annual lights-out event.

“Last year we rolled out ‘I Will If You Will’ to 13 countries and territories so it’s basically a pilot project to see if it would work,” Ridley told journalists in Singapore.

“It worked. So this year, instead of 13, it will be at least 50, we already have at least 50 countries confirmed,” he further added.

Singapore-based Earth Hour’s headline campaign is an annual lights-out activity to underscore energy conservation.

It was observed in 7,000 cities and towns in 152 countries and territories last year, the group said.

Last year the campaign spurred a 120,000-strong petition in Russia that galvanised parliament to pass a law protecting the seas from oil pollution.

Former Botswana President Festus Mogae also pledged to plant one million indigenous trees in four years.

The countries involved last year included Singapore, Sweden, Hong Kong and the United States.

This year’s participating countries include Australia, Britain and South Korea, with celebrities expected to make pledges.

Ridley, speaking at the global launch of Earth Hour 2013, said that the Asia-Pacific region gives the movement its strongest support.

“Asia-Pacific, as a region, is by far the strongest, and Latin America is probably the second,” Ridley said.

“Many campaigns are based out of Europe and based out of the US, Earth Hour is not and maybe that’s a really good strength for us.”

This year’s Earth Hour is scheduled for March 23 at 8:30 pm in participating locations.