Action on climate change is a “moral imperative and an economic necessity” says Prime Minister Carney. But his government’s legislation and policies have not yet risen to those words.
The Prime Minister understands the global climate emergency better than any of his predecessors, as is abundantly clear in his book Value(s). The question is whether he is as committed to tackling climate change as he is to addressing other pressing trade and geopolitical challenges.
A key complication is that federal action on climate has been hampered by misinterpretations of the Supreme Court of Canada opinion that parts of the Impact Assessment Act are unconstitutional. The effect of amendments guided by that opinion has been to shield massive projects with major greenhouse gas (GHG) implications from scrutiny.
Canada urgently needs a revamped legislative framework, starting with a clear assertion of federal authority under the constitution to enact climate laws. A vigorous defence of the federal Impact Assessment Act at Alberta Court of Appeal hearings this month would be a start.
Nature Canada is an intervener in this case, represented by West Coast Environmental Law.
Professor Nathalie Chalifour, a preeminent climate law scholar, has laid out a path to securing and clarifying federal authority to enact climate laws. In her 2025 “Missing the Forest for the Trees” article, Chalifour argues that the Supreme Court majority in the Impact Assessment Act Reference erred by creating a gap in legislative authority governing extraprovincial air emissions such as GHGs.
She writes that under Canada’s constitution, any and all matters must be subject to the authority of either provincial or federal legislatures. It is settled law that provinces have no authority to legislate in relation to acts done outside the province, even if those acts cause damaging pollution to enter the province.
Chalifour concludes that, by default, legislation in relation to extraprovincial pollution must be federally regulated. The courts—ultimately the Supreme Court—must correct this mistake, close the gap, and confirm a broad federal authority to legislate with respect to assessment of major projects that produce GHGs.
Chalifour has another key insight in her 2026 book Climate and the Constitution. She observes that federal and provincial laws are presumed to be constitutional based on three judicially recognized principles, which presumptions can of course be rebutted by evidence.
Chalifour proposes, in essence, a fourth presumption of constitutionality based on the Supreme Court’s recognition that climate change is a global existential crisis.
Given this crisis, climate must be considered a special case constitutionally, and courts therefore should be deferential to federal and provincial legislatures enacting climate laws in good faith.
In future, the Supreme Court should frame its opinions so as to enable non-colourable climate legislation, such as the IAA, and avoid the formalistic rigid approach adopted by the majority in the IAA Reference that discourages legitimate climate legislation.
All levels of government must work cooperatively to enact the laws and policies needed to achieve net-zero emissions. But clearly, federal leadership is a top priority and that leadership must come from the Prime Minister. He and his government need better and more creative legal advice to secure federal legislative authority within constitutional limits.
The Prime Minister would be well-advised to have a chat with Professor Chalifour.
Stephen Hazell
