Protesters march downtown during a climate change rally Saturday in Vancouver. (Andy Clark/Reuters)

Vancouver's Cambie Street Bridge reopened Saturday afternoon after its three northbound lanes were closed to vehicle traffic for a climate change demonstration.

More than 1,000 people turned out for the rally and march, mounted by an organization called Bridge to a Cool Planet.

They hope to put pressure on the federal government to introduce tough measures to curb carbon emissions at the coming Copenhagen climate conference.

"I think the only thing that will make it happen is public pressure pushing it from below," said organizer Kevin Washbrook.

"It's clear that they're not willing to do it on their own without a broad base of people saying, 'Do it now.' You know, we have to have these changes now because we are really running out of time to make a difference on this."

Similar rallies took place across the globe in what was billed the International Day of Climate Action, involving more than 4,500 events in 173 countries, said Washbrook.

In Canada, more than 150 events were scheduled to take place, from metropolitan centres like Toronto and Montreal, to small college towns like Wolfville, N.S.