Former environment and climate minister Steven Guilbeault announced Wednesday that he will resign as a member of Parliament this summer following significant changes to federal climate policy under Prime Minister Mark Carney.
“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,” the Montreal MP wrote in a letter posted on social media.
His announcement comes less than two weeks after Carney and Alberta Premier Danielle Smith signed an energy pact that pledged federal support for a new pipeline to the West Coast, and slowed the pace of industrial carbon pricing.
Guilbeault said the decision comes after “careful consideration” weighing his past seven years as an MP. He said he will remain in the Liberal caucus until he steps down.
“I’m feeling at peace,” he told media in brief comments Wednesday.
Multiple news reports had federal Green Party leader Elizabeth May trying to persuade Guilbeault to stay. “I would have obviously loved to have him join the Green Party,” she said. “But I would have loved to have him stay in Parliament as a backbencher, doing his best from the inside, or as an Independent or what have you.”
The staunch environmentalist has become increasingly disillusioned in recent months by what he has called the dismantling of climate policies since Carney became prime minister in March, 2025, The Canadian Press reports.
The ‘Green Jesus’ of Montreal
Guilbeault, once nicknamed the “Green Jesus” of Montreal, was a power player in Canada’s climate movement, including as a co-founder of Équiterre and the Quebec head of Greenpeace. He’s one of the few people anywhere who’ve attended every United Nations climate summit, dating right back to COP1 in 1995.
On LinkedIn, Canadian Climate Institute Rick Smith recounted the 30 years he’s known Guilbeault as a friend and colleague. “Through many different roles, I’ve watched his incredible dedication and smarts up close,” Smith wrote. “In Parliament and out, he’s always been a public servant in the very best sense of that term—someone motivated first and foremost to do what’s best for Canada and Canadians.”
After witnessing Guilbeault’s leadership on protected areas, toxic chemical and plastics regulation, water conservation, and climate action, “I can’t wait to see what his next chapter brings,” Smith added. “For now, he deserves the thanks of all Canadians for an exemplary effort—always carried off with his characteristic, soft-spoken, good humour.”
Steven Guilbeault was first elected in 2019 during the government of former prime minister Justin Trudeau, CP recalls. He spent time first as Heritage Minister, then nearly four years as environment minister, bringing in significant new policies to lower Canada’s greenhouse gas contributions. That list included a cap on emissions from the oil and gas sector, regulations to make Canada’s electricity grid emission-free by 2050, and a mandate to ramp up electric vehicle uptake so no new gas-powered passenger vehicles were sold after 2035.
In March, 2025, after Carney replaced Trudeau, Guilbeault returned to the heritage portfolio as minister of culture and official languages. He left cabinet in November, 2025, after the initial announcement of Ottawa’s controversial memorandum of understanding (MOU) with Alberta, which committed the two governments to work toward the approval of a new bitumen pipeline.
The final version of that deal was signed by Carney and Smith in Calgary on May 17.
While Guilbeault thanked his constituents in the Montreal riding of Laurier-Sainte-Marie, which he has represented since 2019, he signalled he believes he can accomplish more for the environment outside the House of Commons.
Continuing the Fight
“Around the world, we have demonstrated what we can accomplish with ambition and determination. It is with this same conviction that I wish to continue this fight for the generations who will inherit our precious and unique blue planet,” Guilbeault wrote in his statement.
The Liberals hold a thin majority government with 174 seats in the House of Commons.
Asked on his way into the Liberal caucus meeting whether the MOU was worth it, given Guilbeault’s decision to leave, Carney said, “Absolutely.”
Carney told reporters at the CANSEC military hardware conference in Ottawa earlier Wednesday that he respects Guilbeault’s decision.
“First and foremost what I want to do is thank… Steven Guilbeault for his many contributions,” Carney said.
The prime minister recalled working with Guilbeault when Carney was the United Nations’ special representative on climate action and finance. He said he expects he and Guilbeault will work together again in the future.
“We’ve worked closely together in a variety of areas and I’ve always enjoyed working with him,” Carney said.
In a previous media statement, Guilbeault said he strongly opposed the agreement between Ottawa and Alberta, calling the proposal to exempt Alberta from federal Clean Electricity Regulations “a serious mistake.”
He wrote that “several elements of the climate action plan I worked on as minister of the environment have been, or are about to be, dismantled: the consumer carbon pricing, the zero-emission vehicle standard, the oil and gas sector emissions cap, the framework to eliminate fossil fuel subsidies and the clean electricity regulations.”
Many of Guilbeault’s Liberal colleagues had positive things to say about him on their way into the party’s caucus meeting on Wednesday.
‘Tremendous Respect’
“I have a tremendous amount of respect for him and the work that he does and I really wish him all the best,” said Environment and Climate Minister Julie Dabrusin (L-Toronto-Davenport).
“Steven is a dear friend. I wish him the best in whatever decision he ends up making,” said MP Matt Jeneroux (L-Edmonton Riverbend). “At the end of the day, he has been somebody who I have been able to ask advice for in the past, and I wish him well.”
“I have the greatest respect for him and I understand that after seven years in politics, for various reasons, one can decide to do something else and in other capacities,” said Procurement Minister Joel Lighbound (L-Louis-Hébert).
Transport Minister Steven MacKinnon (L-Gatineau) was also a Trudeau-era minister. He suggested the political landscape has changed since then.
“It’s a different Liberal party… that is meeting the very urgent and critical demands of the moment,” he said. “We’re in a trade war, there are wars in the Middle East, there’s a war in Europe. Indeed, we have a climate change challenge to meet and contribute to, and we’re going to continue doing all of that.”
Last week, the CBC reported that 14 Liberal MPs sent a letter to the prime minister at the end of April expressing their concern about the government’s planned agreement with Alberta. On Tuesday, MP Éric St-Pierre (L-Honoré-Mercier), co-chair of the Liberal Party environment and climate caucus, said he “absolutely” supports the government’s policies, including its “amazing” nature strategy, its “very robust” electric vehicle strategy, and its “very good” methane regulations.
On his way into his party’s caucus meeting Wednesday, Conservative MP Michael Barrett (CPC-Leeds—Grenville—Thousand Islands—Rideau Lakes) said the 14 MPs who signed the letter should come out publicly with their criticisms, CP writes.
“Mr. Guilbeault has the courage of his convictions and has seen that he doesn’t have that alignment with Mr. Carney,” he said.
The main body of this report was first published by The Canadian Press on May 27, 2026
