The protest — dubbed the People's Climate March — was one of a series of events large and small held around the world, including several marches in Canada.
The colourful march stretched along blocks of downtown Manhattan, and comes days before the United Nations Climate Summit there on Tuesday.
Among them were throngs of Canucks who made their way down to the Big Apple — with scores from one Toronto environmental group alone hopping on busses for a 12-hour trek.
Also there was Sierra Club Canada program director John Bennett, who said it was long past time for Prime Minister Stephen Harper to take concrete steps to reduce the country's greenhouse gas emissions.
"Even though he's in control in Canada he's never respected the demand for action on climate change that the population has made. Canadians overwhelmingly want action on climate change and he has not delivered on that."
"We want to bring a message to the United Nations and to Mr. Harper that we want to see some real action to reduce our emissions and that means stop betting on fossil fuels and doing things to reduce our emissions, and to help the rest of the world do the same," Bennett said.
Harper will not be among the 120 world leaders attending the UN summit, a meeting aimed at galvanizing political will for a new global climate treaty by the end of 2015.
His office says Environment Minister Leona Aglukkaq will represent Canada at the summit, and that Harper will discuss climate issues at a related dinner with United Nations Secretary-General Ban Ki-moon, who was among the dignitaries and celebrities walking in the march. Harper will be in New York this week to address the UN General Assembly.
Protest group Toronto 350 said it bussed about 275 people down for the march, while Quebec environmental group Equiterre also organized trips.
Graduate student Aaron Saad, part of the Toronto group, said Canadian marchers made the trip because they're sick and tired of the country's environmental record.
"I think so many Canadians are here because we're so fed up with the way things are going in Canada. We are the source of the tar sands, which has just been such a destructive project for the climate and for local environment and indigenous people," he said.
"We're just so fed up with that and we need some real leadership on really addressing climate change."
There were some rallies held in a number of Canadian cities on Sunday including Toronto, Vancouver and Winnipeg.
_ by Will Campbell in Toronto with files from Ben Shingler in Montreal and the Associated PressSuggest a correction