MONTREAL - They came from every direction on Sunday, as far as the eye could see, gathering by the thousands at Place des Festivals for Earth Day, critical of the government's commitment to the environment.

The main culprit was the Kyoto Protocol, an international treaty on greenhouse gases abandoned by the Harper Conservative's in December 2011. Kicking off the afternoon's celebrations, a symbolic petition was signed in support of the protocol.

"To get out of Kyoto like we did is to go exactly the opposite of the direction we need to take for the future of Canada and the planet," said Richard Bergeron, the leader of Project Montreal.

Standing near Bergeron, NDP leader Thomas Mulcair criticized the economic, social and environmental policies adopted by the federal government and Premier Jean Charest's Liberals.

"There are a lot of people who realize the decisions being taken today are leaving an unfair debt on future generations," said Mulcair.

Coming two days after a violent clash outside of an announcement about Plan Nord, Charest's plan to spend billions on massive development projects in the province's vast north, the student presence in the crowd was strong.

The heavy security was also noticeable, despite student groups calling for protesters intent on violence to stay away.

Many people at the march said they believed Quebec needs another quiet revolution, much like the movement in the sixties that brought sweeping changes to the province.

They are calling for a "Printemps Erable," a Quebec spring.

"The spring is when everything wakes up, so it's like the awakening of the people so people are going to realize that something is terribly wrong," said student Shayne Tupper.

While tens of thousands took to the streets, large swaths of downtown were closed to traffic.

Despite cool temperatures, Equiterre co-founder Steven Guilbeault had hoped that Sunday's march would be the largest environmental demonstration in Quebec's history.

With organizers claiming that up to 300,000 people were present, most impartial estimates were considerably lower.

Attended by over six million Canadians last year, Earth Day was launched in the U.S. on April 22, 1970 to raise awareness about environmental issues.

With files from The Canadian Press.