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Steven Guilbeault makes his way to the Liberal caucus meeting on Wednesday. Mr. Guilbeault says he is leaving politics after nearly seven years.Spencer Colby/The Canadian Press

Former star Liberal recruit Steven Guilbeault confirmed Wednesday his exit from politics, saying he’s decided he needs to pursue his fight against climate change in a different way.

Prime Minister Mark Carney told reporters he’s known for some time that his former cabinet minister could leave and said he understands the decision.

Mr. Guilbeault, who represents a Montreal riding, said he will remain in the governing caucus until he resigns his seat later this summer.

“After almost seven years as a Member of Parliament and Minister, I have come to the conclusion that it is time for me to pursue my fight for environmental protection and the fight against climate change in a different way,” Mr. Guilbeault said in a statement posted to social media.

“I’m feeling at peace,” Mr. Guilbeault told reporters in brief comments after his meeting with the Liberal caucus.

He will make a speech in the House of Commons Wednesday afternoon.

Mr. Guilbeault previously resigned from Mr. Carney’s cabinet over his disagreement with the government’s energy accord with Alberta and its dismantling of marquee climate policies from the Trudeau era. Two sources told The Globe and Mail on Tuesday that the tipping point for his exit entirely from Parliament Hill was a raft of policy announcements over the last two weeks that undid large parts of the policy Mr. Guilbeault crafted when he was environment minister under Justin Trudeau.

The Globe is not identifying the sources, who were not authorized to disclose the private conversations.

While the House of Commons was on break, the government unveiled major proposed changes to environmental assessments and softened the bite that industry will feel from the carbon price. That latter change, made through an accord with Alberta, also paved the way for a new oil pipeline to the West Coast.

Mr. Carney thanked Mr. Guilbeault for his contributions to public life at a Wednesday morning press conference and said he has always enjoyed working with him.

“It’s for him to make decisions about his career,” the Prime Minister said of Mr. Guilbeault.

In a subsequent statement released by his office, Mr. Carney spoke glowingly of the Quebec MP’s contributions. He said Mr. Guilbeault’s work has “always been guided by his convictions and driven by his pursuit of a stronger, more inclusive, and more sustainable future.”

The government remains committed to climate action, the Prime Minister insisted. “We are advancing these missions with the same determination, a new spirit of partnership, and a renewed focus on results,” he said in his statement.

A growing clamour of environmental groups and activists, however, have criticized his approach. They say Mr. Carney has betrayed the climate movement and argue his policies in government run counter to the stand he took on the issue in private life.

Under Mr. Carney the Liberal government has systematically dismantled the policies introduced under former Liberal prime minister Justin Trudeau. The consumer carbon tax, the oil and gas emissions cap, the Clean Electricity Regulations, the electric vehicle mandate, the Clean Fuel Regulations, the two billion trees program, the Canada Greener Homes Loan, and anti-greenwashing rules have each been cancelled, repealed, weakened or suspended.

A discussion paper released on May 12 would give cabinet the power to exempt major projects from the Species at Risk Act’s jeopardy test – the legal standard preventing approved projects from driving species toward extinction.

Still, on nature conservation, the government’s record tells a different story. The nature strategy includes a commitment and plan to protect 30 per cent of its land and oceans by 2030. Canada also quietly tabled the High Seas Treaty in the House of Commons on April 30, a first step toward ratification of the landmark agreement governing biodiversity in international waters. And the spring economic update included $258-million for whale protection. But that was done in recognition of expected increases in West Coast marine traffic from the proposed new pipeline.

Ahead of their closed-door meeting on Wednesday, Liberals commended Mr. Guilbeault’s work to fight climate change and protect the environment and wished him well.

While the Quebec MP was environment minister, his counterpart in the energy department was B.C. MP Jonathan Wilkinson. Both Trudeau-era cabinet ministers are now backbenchers and are leaving elected life this summer.

Mr. Wilkinson told The Globe he believes other MPs on the Liberal side will keep advocating for climate action. Asked about Mr. Carney’s unwinding of the marquee policies that he and Mr. Guilbeault brought in under Justin Trudeau, the MP said the world has changed.

Climate has taken a “step back everywhere,” Mr. Wilkinson said, pointing to the experience in Canada, Europe, Japan and South Korea.

“But I do think, and I do believe that the Prime Minister is committed to addressing the climate issue,” Mr. Wilkinson said. “I think you will see the government take important steps forward.”

Mr. Wilkinson is resigning his B.C. seat at the end of the sitting and moving to Brussels, where he will be Canada’s ambassador to the European Union.

Mr. Carney will soon have four by-elections to call. In addition to Mr. Wilkinson and Mr. Guilbeault, Toronto Liberal MP Nate Erskine-Smith is also expected to resign. As is former NDP Quebec MP Alexandre Boulerice, who is currently sitting as an independent.

Though public opinion polling shows Mr. Carney’s team with the upper hand, the by-elections are expected to be hotly contested races. The Liberals are presiding over a narrow two-seat majority and will be aiming to bolster their bench strength while opposition parties try to knock them back to a minority government.

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