Liberal MP Steven Guilbeault is expected to address members of Parliament on Wednesday.Spencer Colby/The Canadian Press
Former Liberal minister and career environmentalist Steven Guilbeault will announce his resignation from Prime Minister Mark Carney’s caucus on Wednesday, three Liberal sources told The Globe and Mail.
Two of the sources said Mr. Guilbeault will also quit as a member of Parliament effective this summer. They said the MP will address the Liberal caucus on Wednesday morning. The sources did not clarify whether he would immediately resign from the Liberal Party and sit as an independent for the remainder of his tenure.
Those two sources and two others said Mr. Guilbeault is also expected to address Parliament on Wednesday afternoon and has invited former staff to attend.
The Globe is not identifying the sources, who were not authorized to discuss the still confidential plans.
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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.
The Quebec MP had stayed in caucus in the hopes that he could still influence government policy, but two of the sources said it had become clear to Mr. Guilbeault that his advice was not being heeded.
They pointed to the policy changes announced by Mr. Carney’s government in the past two weeks as the tipping point for Mr. Guilbeault. 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. Guilbeault’s office declined to comment on Tuesday. His expected exit was first reported by CTV News.
Two of the sources said that they expect the Liberals can hold on to Mr. Guilbeault’s riding in a by-election, but they cautioned that Mr. Carney could be creating a longer term political liability for the Liberals because of his new climate stand. Their concern stems in part from the fact that the Liberals attracted many New Democrat voters in the last election. Also, the environment and climate remain an important issue for a subset of the core Liberal base.
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The Prime Minister’s Office did not respond to a request for comment. On his way into cabinet on Tuesday morning, Mr. Carney did not reply when asked by The Globe if Mr. Guilbeault was going to quit. He will speak to media on Wednesday before attending the Liberals’ weekly caucus meeting with Mr. Guilbeault.
Mr. Guilbeault is a polarizing figure in Canadian politics. He is widely vilified in the Prairie provinces over his opposition to the oil industry but he is revered in Quebec. He was considered a star recruit when he agreed to run for then-prime-minister Justin Trudeau in 2019 and crafted many of the climate policies that angered the Alberta government and which Mr. Carney has now repealed or diluted.
Since coming to office, the Prime Minister has also cancelled the consumer carbon price, scrapped the emissions cap on the oil and gas sector, repealed the electric-vehicles mandate, and shuttered a program to plant two billion trees.
Mark Carney with Mr. Guilbeault in Montreal in April, 2025.Adrian Wyld/The Canadian Press
Mr. Guilbeault’s departure from the Liberal caucus wouldn’t change the balance of power in the House, but it would weaken the already-thin majority that Mr. Carney obtained through floor-crossings and by-elections that were held in April.
At the time of the 2019 election, climate and environment issues were a top priority for voters and the government, but the pendulum has decisively swung away from that focus and toward the economy and affordability.
On Parliament Hill on Tuesday, ministers and Liberal MPs were careful not to criticize Mr. Guilbeault and lauded his work over the past seven years in government.
Health Minister and Quebec MP Marjorie Michel called him a wonderful colleague and said she respects his decision.
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“Everyone has their own line, but I think the government is going in the best direction possible, including on the environment,” she said in French.
Some Liberal MPs are quietly raising concerns behind the scenes, with 14 members of Mr. Carney’s caucus sending him a letter in April that questioned some of his climate policies. The Prime Minister shrugged off those concerns on Monday, noting that there are 160 other members of the Liberal caucus who have a different perspective.
Industry Minister and Quebec MP Mélanie Joly told reporters on Tuesday that she considers herself to be part of the Liberals’ environment caucus. And despite previously championing the climate policies brought in by Mr. Trudeau, she now says she supports the approach taken by Mr. Carney.
Industry Minister and Quebec MP Mélanie Joly arrives to cabinet on Parliament Hill in Ottawa on Tuesday.Sean Kilpatrick/The Canadian Press
The plan to approve another crude oil pipeline though to the West Coast remains politically sensitive. Housing Minister Gregor Robertson opposed the Trans Mountain Pipeline expansion in 2016, when he was Vancouver mayor.
Asked on Tuesday whether he supports the new pipeline, his first response was: “There is no pipeline proposed yet.”
Pressed on what that means regarding the pipeline the Prime Minister has already pledged to get built, Mr. Robertson said he would support it if it meets environmental standards and the conditions of British Columbia and Indigenous groups.
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Climate activists are increasingly disagreeing with the government’s approach. Green Party Leader Elizabeth May said the rapid-fire changes announced in the past few weeks are reminiscent of the flood-the-zone strategy championed by the team around Donald Trump.
She said it seems like decades of environmental policy is now “open for the bulldozer.”
Caroline Brouillette, executive director of Climate Action Network Canada, said Mr. Guilbeault’s decision should be viewed as an indicator of how climate-focused MPs and voters are feeling.
“The Prime Minister should think about the millions of Canadians who elected him thinking they could trust him on climate action because of his reputation, and are now feeling betrayed,” she said.
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Ms. Brouillette said her group has done public-opinion polling that shows the Liberals’ new climate approach could be a vulnerability with voters in key swing ridings. That sentiment was echoed by a Liberal source in Quebec who said it could make it more difficult for the party to pick up a seat when Montreal MP Alexandre Boulerice resigns later this year.
But the political landscape has shifted dramatically since the 2019 election, and Shachi Kurl with the Angus Reid Institute said there’s also a chance that Mr. Carney is gaining political capital with the Canadian electorate even as he is spending it with others.
Canadians are in a crisis mindset because of Mr. Trump, and the economy, affordability and jobs are the issues voters are asking Mr. Carney to address, Ms. Kurl said.
That change in focus was underscored by Quebec Liberal Leader Charles Milliard, who spoke at the Economic Club of Canada on Tuesday.
“Mr. Carney is very popular in Quebec right now,” he told the business crowd.
With reports from Jenn Thornhill Verma and Laura Stone.