The skyline of Toronto's downtown is dimmed as many of the lights are turned off for Earth Hour on Saturday. (Darren Calabrese/Canadian Press)Canadians eager to draw attention to climate change joined people from Beijing to Paris in turning off their lights on Saturday during the second annual Earth Hour.

About 250 people gathered in Halifax's Grand Parade to watch Mayor Peter Kelly flip off the town hall's lights at 8:30 p.m. AT.

The World Wildlife Fund is encouraging people to shut off non-essential lights — or at the very least dim them — from 8:30 p.m. to 9:30 p.m. local time.

Kelly admitted he was a little disappointed that nearby office buildings left their lights on.

"We had thought everybody would be part of this process, and unfortunately, they are not," he said, gesturing to a nearby office tower where many lights remained on.

However, Kelly said, when cities turn off the lights in municipal buildings it "engages the citizens" and helps people feel they're part of a change in energy use across the globe.

Timothy Mosdell of Bell Island, N.L., told CBC News that he originally forgot Earth Hour was scheduled for Saturday night, but remembered in the nick of time and turned his lights off.

He said he believed the organizers were hoping "that people don't just do the symbolic thing tonight but that [they] change their actions going forward."

He said the event has already had an impact on him.

"I think from now on, I'll stop driving as much as I [can]."

'Symbols are powerful'

Lights went out on Parliament Hill in Ottawa, just as Toronto's landmark CN Tower, usually illuminated by bright lights that run up its 550-metre column, went dark at 8:30 P.M. ET sharp.

About 150 people hold candles below the Peace Tower as the lights on Parliament Hill are turned of for Earth Hour in Ottawa on Saturday. (Fred Chartrand/Canadian Press0Kevin O'Donnell, the CEO of the federal and Ontario riding associations of the Green party who organized the Ottawa event, acknowledged Earth Hour is a symbolic event.

"In a sense, I agree. It is symbolic, but I don't take it as criticism," O' Donnell told CBC news.

"Symbols are powerful."

By turning out for Earth Hour, he said, participants are signalling sustainability and climate change "are important to us and we want the government of today and governments of tomorrow to do something about it."

O'Donnell said response for the Ottawa event was "outstanding."

"We did the usual things — email our membership, we put out community notices, [and contacted] the media."

"But this year, web sites like Facebook and Twitter came along and all of a sudden everybody is talking about it."

The Independent Electricity System Operator, which operates the electricity market in Ontario, said 920 MW of power were saved during the hour, a reduction of six per cent compared with typical demand.

Events planned across country

More than 250 municipalities across Canada have pledged support, and almost 70 public events are planned, World Wildlife Fund Canada said.

A recent survey suggested 81 per cent of Canadians were expected to turn off their lights for the hour, the group said.

"Turning off our lights for an hour isn't going to solve climate change, but what it does do is show individuals that they can make a difference in the fight against global warming and sends a really strong message to world leaders that action is needed now," said Tara Wood of WWF Canada.

The conservation organization's offices in Sydney, Australia, introduced Earth Hour to raise awareness of climate change.

Nearly 4,000 municipalities in 88 countries were expected to take part, the WWF said. Last year, only 400 cities participated; Sydney held a solo event in 2007.

A number of key landmarks will fade to black, including New York's Empire State Building, and the Christ the Redeemer statue in Rio de Janeiro.

Renowned landmarks go dark

Australia's famed Opera House dimmed Saturday as Sydney became the first major city to plunge itself into darkness.

The Eiffel Tower is shown just after its 20,000 bulbs were turned out on Saturday, at 8.30 p.m., for five minutes. (Thibault Camus/Associated Press)China participated for the first time, cutting the lights at Beijing's Bird's Nest Stadium and Water Cube, the most prominent 2008 Olympic venues.

In Egypt, the Great Pyramids and the Sphinx were darkened.

In Greece, floodlights at the Acropolis in Athens were switched off and an outdoor concert was staged on an adjacent hill, which many Athenians approached in a candlelight procession.

In Paris, the Eiffel Tower, the Louvre and Notre Dame Cathedral were among 200 monuments and buildings that went dark. The Eiffel Tower, however, only extinguished its lights for five minutes for security reasons as visitors were on the tower, WWF France spokesman Pierre Chasseray said.

With files from the Canadian Press