Prime Minister Mark Carney thanked former cabinet minister Steven Guilbeault for his contributions to government as the Liberal MP prepared to announce his resignation Wednesday.

Guilbeault, a staunch environmentalist, has become increasingly disillusioned in recent months by what he has called the dismantling of climate policies under Carney.

The Quebec MP quit Carney’s cabinet last year after the announcement of Ottawa’s energy deal with Alberta, which included a memorandum of understanding to work toward the approval of a new bitumen pipeline.

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 defence 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 and called the proposal to exempt Alberta from 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.”

Guilbeault, who served as environment minister under Prime Minister Justin Trudeau, was also Carney’s culture and official languages minister for a few months.

He has represented the Montreal riding of Laurier-Sainte-Marie since 2019. Before politics, he also worked with Greenpeace, Deloitte and Copticom.

This report by The Canadian Press was first published May 27, 2026