People in more than 7,000 cities and towns across the planet turned off lights for an hour from 8:30 to 9:30 p.m. local time.
Several events around Canada marked the occasion. But some efforts did not have much tangible impact in a couple of provinces. Ontario reported that power demand was down 2.7 per cent, while in Nova Scotia the dip was less than one-half of one per cent.
Messages were posted on the websites of utilities in New Brunswick and B.C. urging all residents to power down to show their concern for the global environment.
Coming out on top, Vancouver was crowned the winner in the WWF Earth Hour City Challenge out of 66 participating cities from Canada, India, Italy, the U.S., Norway and Sweden.
"We have the power to make significant changes in our city that address climate change," said Vancouver city councillor Andrea Reimer.
The contest was created in a bid to take steps toward creating greener, cleaner and more sustainable cities to live in.
Vancouver was also named the WWF People’s Choice winner with the highest number of votes online.
According to the WWF, 13 million Canadians turned off their lights for an hour last year. It’s not yet known whether that figure was topped this year.
Canadian astronaut Chris Hadfield, the current commander of the International Space Station, posted pictures of cities lit up before Earth Hour.
Hadfield wanted to take pictures of cities like San Francisco and Las Vegas while the lights were out. However, he tweeted that the orbital mechanics did not support seeing those efforts.
"Let's each help a bit," tweeted Hadfield.Suggest a correction