People's Party of Canada Leader Maxime Bernier says teenage climate activist Greta Thunberg's call for governments to act on climate change is creating panic among young people who are needlessly fearing for their futures.

"I don't like what this young lady, Greta, 16 years old, is saying. I'm saying to Canadians, there is no climate emergency and no crisis," Bernier said about the Swedish girl's scolding of world leaders this week at a United Nations climate summit in New York.

Bernier, 56, has been criticized for tweeting that Thunberg is mentally unstable, but he later walked back that comment.

Nevertheless, he believes Thunberg's views are too extreme, he said in an interview Wednesday in Vancouver.

"We cannot deal with public policy on panic and sentiment and fear," he said. "We must build public policies on reason and facts. I think the radical environmentalists are saying that because they don't want to have any debates about it. They want us to panic and to act. No, we won't do that and that's not the position of our party."

Against carbon tax

Bernier said more studies are needed to determine the cause of climate change, which he said is only partly due to human activities.

"Why not have more studies about the impact of the sun on our planet?" he said. "I'm honest with the population on climate. The environment is shared jurisdiction with the provinces. They can deal with that. We won't sign the Paris agreement, we won't impose a carbon tax, we won't impose more regulation because we don't believe there's a crisis or emergency and that will it will be the end of the world if we don't do anything in 10 years."

Bernier said he doesn't believe his daughters Megan, 20 and Charlotte, 17, will participate Friday in student protests related to climate change, similar to those held a week earlier, based on anxiety created by "extreme environmentalists."

Kathryn Harrison, a University of British Columbia political science professor who studies climate change, said the consensus on the impact of climate change is so extraordinarily strong that the views of politicians who ignore the science are "frightening."

Environmental activist Greta Thunberg, of Sweden, addresses the Climate Action Summit in the United Nations General Assembly, at U.N. headquarters, Monday, Sept. 23, 2019. (Jason DeCrow/The Associated Press)

"I really hope that Canadian voters are hoping for better from their parliamentarians because so many issues turn on science," she said, adding rejecting evidence produced by countless peer-reviewed studies suggests experts can't be relied upon for other public-policy issues, including management of natural resources to benefit the economy.

Earlier Wednesday, Bernier began a speech in Surrey, outside Vancouver, with protesters yelling "PPC, shut it down!" outside a hotel ballroom where a boisterous crowd frequently applauded his proposals to limit immigration.

Slash immigration numbers

Security officers barred a door before about a dozen protesters dispersed, some with signs in support of immigrants and refugees.

Much of Bernier's speech at a Surrey Board of Trade event focused on immigration, which he said requires a "discussion" that, unlike his opponents, he's not afraid of having in a democracy like Canada.

Bernier said he would slash immigration numbers nearly in half to about 150,000 people a year and 50 per cent of those would have to be "economic" immigrants, such as skilled workers and entrepreneurs.

He said he's against "mass immigration" but is not anti-immigrant and believes Canada should accept "real refugees," not those trying to enter Quebec and other parts of the country without crossing at official border checkpoints.

Bernier estimated 40 per cent of the approximately 45,000 refugees who have crossed into Quebec from the United States in the last several years will have to be deported.

"It's not me who's saying that, it's the Department of Immigration because they're not real refugees," he told members of the business community and the public at a Sheraton hotel.

"They will have to be deported in a couple of years from now and that will be very difficult because maybe they will have kids and the kids will be at school and that will be tough to do that."

His solution is to erect a fence at Roxham Road in Quebec, where many migrants cross because a road in New York state and one on the Canadian side are separated by just a few metres of brush, and to have RCMP officers stand guard to direct people to cross at an official border crossing, Bernier said.