QUEBEC -- Erin O'Toole began Wednesday telling voters he's not leading "your dad's Conservative Party," but ended the day sharing a stage with former prime minister Brian Mulroney, who compared the Tory leader's preceding months to the lead-up to his 1984 election win.

The 82-year-old who governed Canada under the former Progressive Conservative banner from that year until 1993 walked onto a stage that evening before an audience of supporters in Orford, Que., as they chanted his name.

He told the crowd of about 170 a story of getting a call from O'Toole about five months earlier where the Conservative leader explained pollsters were predicting he would lose, there was negative media coverage and there was restlessness within the party.

"I said, `Erin, I think you should be thrilled … because that's exactly what they said about me three months before the election in `84 when we won the largest majority in the history of Canada,"' Mulroney said.

Mulroney drew similarities between himself and O'Toole, saying they both married up and were lawyers.

The former prime minister said O'Toole offers strong, steady and visionary leadership, and will have to tackle ending the COVID-19 pandemic and reviving an "anemic" economy.

Mulroney also foreshadowed that there "will be tough and deep structural changes to be made for our country if we are to enhance prosperity and influence of Canada."

"Some of these decisions may make Erin unpopular, of course, I never was," he told the crowd.

Mulroney said he wasn't interested in attacking anyone in the campaign and was there because he believes in electing O'Toole.

His appearance at the event came one day after former prime minister Jean Chretien, who was in power from 1993 to 2003, campaigned for Liberal leader Justin Trudeau in Ontario.

Both former leaders hit the campaign trail with only days left before Canadians head to the polls on Monday in hopes of giving their respective parties a boost. Polls show the Conservatives and Liberals locked in a tight race.

One of the accomplishments Mulroney is remembered for is his environmental policies, including the 1991 signing of a historic air quality agreement with the United States.

O'Toole now touts his climate change plan as proof he has renewed the party, acknowledging that it didn't live up to the expectations of Canadians in the past two elections when it comes to the environment.

."We're not your dad's Conservative Party anymore," he said earlier Wednesday.

O'Toole was asked to clarify his recent comments to the Toronto Star, in which he said his plan was an "alternative" to the federal carbon price and it would be up to provinces such as Ontario that currently pay that price to decide whether to make the switch.

The Tory leader has faced criticism from within his own tent for promising a Conservative carbon price on fuel after campaigning during his leadership race to scrap the plan introduced by the Liberals in 2019, which set a minimum price on carbon emissions in provinces that don't have equivalent provincial prices - a law that was challenged by Saskatchewan, Ontario and Alberta.

The Supreme Court of Canada in March ruled that the federal carbon price is entirely constitutional.

O'Toole has said that under his system, the money consumers have to pay through the Conservative carbon price on gas would be sent to personal savings accounts they could then use to make green purchases.

He rejected the suggestion that he has changed his party's policy by allowing provinces to choose among carbon pricing plans.

"That is exactly what I said in April when I launched this plan," O'Toole told reporters in Quebec's Saguenay region.

"It's a very detailed plan to meet our Paris targets and to promote collaboration on a range of issues to pricing carbon to electric vehicles to technology," he said.

"We have to work together as a country -- provinces and the federal government -- to meet our targets and have a strong economic recovery."

The Conservatives haven't detailed the cost of their proposed loyalty rewards-style program in their election platform, or how it would track people's carbon consumption and their points-based shopping.

O'Toole called his plan innovative and pledged to work with provinces on ways to reduce greenhouse gas emissions without fighting with premiers.

Allowing provinces to decide their own fate on issues from health care to climate change has been a central part of the Conservative leader's pitch to prospective voters, as well as to Quebec Premier Francois Legault, who he promised to give more power over areas such as immigration.

Liberal candidate Steven Guilbeault has criticized O'Toole's approach, recently posting to Twitter a July 2020 video in which O'Toole, then running for the Conservative leadership, said that if a province chose to do nothing on climate change, he would allow that.

In the video, O'Toole also said that the Tories needed to have a "real" climate change policy in the next election or they would lose.

Since hitting the campaign trail, O'Toole has faced questions over only committing to reduce greenhouse gas emissions by 30 per cent below 2005 levels by 2030, not the higher target of between 40 to 45 per cent that the Trudeau government submitted to the United Nations ahead of an international conference this fall.

Stewart Elgie, a law and economics professor at the University of Ottawa who chairs the Smart Prosperity Institute, said O'Toole deserves credit for adopting a carbon price, something former leaders Andrew Scheer and Stephen Harper did not.

Unlike the Liberals' carbon price, which is set to rise to $170 per tonne by 2030, the Conservatives' charge would start at $20 per tonne and not rise higher than $50.

Elgie said the lower price means it won't be as effective as the Liberals' at reducing levels of greenhouse gas emissions.

And while the proposed savings accounts is an interesting idea, he said implementing it would be a "nightmare."

"How are you going to track the individual carbon footprints of every Canadian and look at every purchase they make?" asked Elgie.

Michael Bernstein, executive director of Clean Prosperity, said it's encouraging that O'Toole appears flexible on his carbon pricing plan, saying the simplest solution would be to keep the existing one in place.

"It works and returns all the money back to Canadians. But if O'Toole wanted to improve the carbon tax policy while giving it a Conservative spin, he could convert the rebates into tax cuts."

This report by The Canadian Press was first published Sept. 15, 2021.