OTTAWA — Steven Guilbeault, the Quebec Liberal MP known for his long career as an environmental activist, resigned from Prime Minister Mark Carney's cabinet on Thursday, citing irreconcilable differences over a new federal-provincial agreement with Alberta that he views as a major setback for climate action.
Guilbeault's departure marks the end of his six-year tenure in federal politics, where he spent much of his time advocating for aggressive environmental policies. The decision, according to sources close to the matter, had been brewing for months amid growing tensions within the Liberal Party over the direction of climate and energy policy under Carney's leadership.
Guilbeault first entered Parliament in September 2019 after winning the Liberal nomination in a Montreal riding earlier that year. A founder of Quebec's Équiterre environmental organization, he left the group in 2018 to pursue politics under then-Prime Minister Justin Trudeau. Initially appointed as heritage minister, Guilbeault was shuffled to the environment portfolio following the 2021 election, where he oversaw key initiatives including legislation to lock in Canada's emissions reduction targets and regulations on oil and gas emissions caps, electric vehicle mandates, methane reductions from oil production, and clean electricity rules aimed at achieving a net-zero grid—originally targeted for 2035 but later extended to 2050.
His endorsement of Carney for Liberal leadership came on January 21, praising the former Bank of Canada and Bank of England governor for navigating economic crises. “I know he’s the right person to help bring us into the next phase of our work to support Canadians, to build a strong economy and to fight climate change,” Guilbeault said at the time. However, that support was soon tested. About a month later, Carney announced plans to eliminate consumer carbon pricing—a policy Guilbeault had staunchly defended despite political backlash—yet Guilbeault maintained his backing.
When Carney assumed the prime ministership, he retained Guilbeault in cabinet but reassigned him from environment to the newly titled minister of Canadian culture and identity, formerly heritage. Guilbeault retained oversight of Parks Canada and was appointed Quebec lieutenant, a role signaling trust in his regional influence. Despite the demotion from the environmental file, Guilbeault stayed on, even as Carney sidelined several left-leaning MPs from Trudeau's inner circle.
Tensions simmered through the fall as Carney's government avoided discussions on emissions targets and floated support for a new oil pipeline as a priority infrastructure project. Sources familiar with the situation said Guilbeault had warned Carney's office as early as spring that federal endorsement of a pipeline would jeopardize his position in cabinet. Like many Liberals, he observed the developments warily, particularly as Carney referred projects to the Major Projects Office and engaged in negotiations with Alberta Premier Danielle Smith on a climate and energy pact.
The breaking point came on Monday, November 23, when CBC reported details of a memorandum of understanding (MOU) set to be signed between the federal government and Alberta on November 27. The agreement, according to the report, outlined significant rollbacks on environmental regulations, including the clean electricity rules, without corresponding increases in industrial carbon pricing. It also potentially exempted a new pipeline from British Columbia's oil tanker ban on its coast—a provision that alarmed environmental advocates.
Guilbeault requested and received a briefing from Carney's office on the MOU's contents prior to that day's cabinet meeting, which was unusually scheduled for 3:30 p.m. instead of the typical 10 a.m. start. Attendees included Marc-André Blanchard, deputy clerk of the Privy Council, and Christiane Fox, associate secretary to cabinet. Reporters noted Guilbeault arriving at the cabinet room stone-faced, brushing past questions without comment. Minutes into the meeting, he briefly exited, met with Housing Minister Gregor Robertson in a nearby office, and then returned.
After the cabinet session concluded, Guilbeault was seen in the hallway behind the cabinet doors, appearing visibly unhappy. He then met privately with Carney for about an hour, voicing his strong objections to the MOU but stopping short of resigning at that point. Later, he received a written copy of the document, which not only scaled back emissions-cutting regulations but also extended federal investment tax credits to enhanced oil recovery projects.
Enhanced oil recovery involves capturing carbon dioxide from industrial sources and injecting it underground at oilfields to boost production by increasing pressure in the rock formations. While the CO2 is stored, critics like Guilbeault argue it effectively subsidizes fossil fuel extraction. The original tax credits had explicitly excluded this technology to avoid incentivizing more oil output. Guilbeault and Green Party Leader Elizabeth May had previously heard rumors of such changes ahead of the federal budget, which nearly derailed May's support.
Guilbeault had secured assurances from the Prime Minister's Office that enhanced oil recovery would not be included in the budget or added later, and he was tasked with persuading May to back the government. On November 17, May became the only non-Liberal MP to vote in favor of the budget, a move that underscored fragile alliances on environmental issues.
By Wednesday night, November 25, Guilbeault's patience had worn thin. He sent a letter to Carney stating that, given the MOU's terms, he could no longer serve in cabinet. The next day, in Calgary, Guilbeault spoke directly with Carney and Blanchard before formally tendering his resignation. In a social media post announcing his decision, Guilbeault wrote, “Despite this difficult economic context, I remain one of those for whom environmental issues must remain front and centre.” He added, “That is why I strongly oppose the memorandum of understanding between the federal government and government of Alberta.”
The resignation highlights deepening rifts within the Liberal caucus over Carney's pragmatic approach to balancing economic growth with climate goals. While Carney has emphasized job creation in energy sectors, particularly in oil-rich Alberta, environmentalists and some party members fear a dilution of commitments made under previous leadership. The MOU's provisions, if finalized, could reshape federal climate strategy, potentially prioritizing industrial partnerships over stringent regulations.
As the November 27 signing date approaches, questions linger about the agreement's full impact. Alberta officials have praised the deal as a win for energy security, though details remain under wraps beyond leaked outlines. For Guilbeault, now back on the backbenches, his exit serves as a stark reminder of the challenges facing progressive voices in a government navigating economic pressures.
Looking ahead, Guilbeault's departure could influence Liberal unity, especially in Quebec, where environmental concerns resonate strongly. Party insiders suggest it may prompt further debates on climate policy as Carney's administration pushes forward with its agenda. Meanwhile, opposition parties, including the Greens and NDP, have seized on the resignation to criticize the government's direction, calling for a recommitment to ambitious emissions reductions.