A protester holds a '350' sign during a march in Taipei. (Chiang Ying-ying/Associated Press)The first of a series of climate change protests planned by activists in countries around the world got underway in Australia on Saturday.

The number 350 is at the forefront of more than 200 events across the country. In Sydney, the bells of St. Mary's Cathedral pealed 350 times. Elsewhere, activists formed a giant 350 with their bodies in front of the Opera House.

Organizer Blair Parese said those taking part in the International Day of Climate Action are calling for a cut in carbon emissions to a specific level.

"Three-hundred and fifty is 350 parts per million of carbon [dioxide] in our atmosphere. That's what most scientists are saying we have to get back to. We're now at 387, so that's a real shift in thinking away from something we have to do in the future to something we need to do right now, and below our current levels," she said.

"It's the number humanity needs to get back to as soon as possible to avoid runaway climate change," the organizers warn on their website.

A rally was held at Queen's Park, Ontario's legislature grounds, on Saturday afternoon as part of the International Day of Climate Action organized by 350.org. (Showwei Chu/CBC)Rallies were planned in 170 countries, including Canada. There were events scheduled for communities across the country, from Corner Brook, N.L., to Victoria, B.C.

Fill the Hill was the slogan for a rally held in Ottawa. Participants were to form an hourglass with their bodies to tell politicians that time is running out to fight climate change.

With only 43 days left before the United Nation's climate change conference in Copenhagen, the idea is to pressure politicians to stop bickering and negotiate a climate treaty that will cut emissions enough to solve the problem.