Provincial governments arguing that the centrepiece of Ottawa’s plan to combat climate change intrudes on their powers met a wall of skepticism at the Supreme Court of Canada on Tuesday.

Federal law sets minimum national standards for the pricing of carbon emissions. When a province does not have its own legislation meeting those standards, Ottawa imposes its own carbon price.

The federal government argues that the case is about more than just climate change, but about the national capacity to meet an existential threat. At least five of the nine judges made multiple comments suggesting sympathy for that view.

“What if one province decides to do nothing because they don’t believe in climate change?” Justice Suzanne Côté asked Mitch McAdam, representing the Attorney-General of Saskatchewan, in the first in-person hearing at the court since the COVID-19 pandemic began in the winter. “It may happen.”

“That’s federalism and that’s democracy,” Mr. McAdam replied. “Where the provinces have jurisdiction, they can make decisions about how to exercise that jurisdiction. If that’s an unpopular decision, they have to go to the polls and the electorate can vote them out at the next election.”

At the heart of the case is the national power-sharing bargain made at Confederation in 1867, when greenhouse gas emissions causing a warming of the planet were unheard of. Canada’s founding Constitution did, however, give the federal government the power to address matters of national concern, as part of its authority over “peace, order and good government.”

Saskatchewan, Ontario and Alberta each asked the appeal courts of their provinces to give an advisory opinion on whether the carbon-pricing law is constitutional. Three other provinces, Manitoba, New Brunswick and Quebec, are intervening at the Supreme Court to argue the law is unconstitutional. B.C., also intervening, says the law is properly within federal powers. Only the Alberta Court of Appeal said the law is unconstitutional.

Saskatchewan, which went first before the Supreme Court, called the national-concern power “illegitimate.” That prompted a degree of umbrage from the mild-mannered Chief Justice Richard Wagner, who said that position goes against “all our jurisprudence.” The chief justice asked him whether it isn’t true that Canadian law is a living tree, evolving since the time of Confederation.

“This is about ripping the tree out by the roots and replacing it with a new tree,” Mr. McAdam replied.

Justice Michael Moldaver called that a “gross overstatement,” and said climate change is an existential threat, “doubly so in terms of Canada, that is surrounded by water on three sides. And particularly the Arctic. There’s evidence before the court that we are already seeing the effects.”

He put the same question asked by Justice Côté (and at least three others) to Mr. McAdam – How could the provinces ensure they would do what is needed to address emissions? – and when Mr. McAdam tried to explain how Saskatchewan is dealing with climate change, with a carbon price for industrial emitters but not a price for consumers at the gas pumps, Justice Moldaver cut him off and insisted on knowing how the provinces could ensure an effective, countrywide response.

Mr. McAdam responded that the legislation is “Ottawa knows best, it’s a Big Brother type of legislation.”

Guy Pratte, representing the federal government, told the court that the law is not intended to weaken the provinces but to “begin the process of healing the planet.”

He took aim at something Justice Thomas Wakeling of the Alberta Court of Appeal had written in a decision in February – that the federal law gives Ottawa such wide ambit to police emissions that it could some day bar Albertans from “heating their homes above sixteen degrees Celsius, driving gasoline-powered motor vehicles, raising cattle.” Mr. Pratte said: “Conjuring up the possibility that we’ll regulate toasters or cows is not really within the realm of” the federal legislation.

But Justice Malcolm Rowe shot back, referring to the cows, “I don’t know, they make a lot of methane.” He was one of two judges who expressed some sympathy for the provinces opposed to the carbon-pricing law.

Echoing Mr. McAdam of Saskatchewan, he mocked the notion that the law was an example of “co-operative federalism,” the idea that the federal and provincial governments can work together toward a common goal. The Supreme Court has said in previous federalism cases that it supports flexibility in the sharing of power between the two senior levels of government.

“This is ‘co-operative federalism – or else,’ ” he said. “To refer to this as ‘co-operative federalism’ is really to play with words.”

Justice Russell Brown was the second judge who seemed to be receptive to the provinces opposed to the law.

“The question isn’t whether the federal government can act against climate change. The question it seems to me is whether the way it has done so in this statute is ultra vires [beyond its powers].”

The hearing continues on Wednesday. The court’s deliberations are expected to take several months.

The Globe and Mail, September 22, 2020