Environmental protests happened all over the world as part of a global day of action on Saturday, most notably in Copenhagen where the United Nations Climate Change Conference is underway.

Tens of thousands of activists converged on the Danish capital demanding "climate justice" from world leaders - which in real terms means signing a legally binding deal to reduce carbon emissions.

Things got heated at one point, prompting police to arrest more than 600 people, but the demonstration was largely peaceful.

And in Toronto, organizers planned a candlelight vigil for 7pm, with participants taking their message to Queen’s Park.

Canada's environment minister, Jim Prentice, arrived in Denmark on Saturday and will take part in the summit next week.

A draft climate pact submitted on Friday calls for developed countries to cut 25 to 40 per cent off 1990 emission levels by 2020.

Ad in the Copenhagen Airport sponsored by the Global Campaign for Climate Action. (Courtesy of mayormiller's Twitter feed)