The demonstration was intended to coincide with worldwide rallies scheduled two days before the start of the United Nations Climate Summit in New York.
The United Nations says the goal of the summit is to promote a global agreement that would limit worldwide temperature increases to less than 2 C.
The organization says no negotiating will be taking place during the conference on Sept. 23, though the gathering intends to show leaders of all types are taking action.
Traffic was snarled in Vancouver as protesters walked through the streets, and many in the crowd were waving placards protesting the Enbridge Northern Gateway pipeline project.
If built, the pipeline would ship 525,000 barrels of oilsands crude per day from the Edmonton area to Kitimat, B.C., where the material would then be shipped to Asia.
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