Lawyers for Saskatchewan and its allies warn that Ottawa's right to impose a carbon price on consumers will undermine the province's sovereignty under the Constitution.

"Granting Canada this level of regulatory power over (greenhouse gas emissions) will cause the federal government's unlimited, intrusive regulatory capacity for provincial affairs," said William Gould for the New Brunswick Attorney General, an intervener in the case, said Wednesday. "It starts here."

The counselor of Saskatchewan opened a two-day hearing before the appellate court. He argued that the provincial constitutional challenge with regard to carbon taxation at federal level was due not to climate change but to differences in power.

"It's not about whether climate change is real or not," said Mitch McAdam. "The Saskatchewan government is not made up of a series of denials of climate change."

He said the question was whether provinces were "sovereign and autonomous within their jurisdictions" under the Constitutional Law.

"Or can the federal government intervene in accordance with our constitution if it believes that provinces do not … properly exercise and act on their responsibility?

"That's what this case is about."

The evidence presented indicates the severity of climate change and the effectiveness of carbon pricing is irrelevant, McAdam said.

"The fact that climate change is a serious problem does not override the Constitution."

The legal position of Ottawa is that climate change is a national concern and the federal government has the power to levy a carbon tax under the constitution, whose state laws "for peace, order and good governance of Canada" can be issued ,

Alan Jacobson, a lawyer from Saskatchewan, argued that Ottawa does not reject the constitutional review to use the causes of a "national concern."

"How does an Ottawa policy become a national concern?" He asked.

Jacobson said that "peace, order and good governance in Canada" has far-reaching implications and should be addressed with caution by the court.

"It's radical and intrusive. It's absolute and exclusive, "he said. "It wants to displace the provincial space that exists today over these areas."

Arguments that Canada is right because it has international commitments to reduce greenhouse gas emissions should be rejected, Jacobson added.

"Ottawa is not a big brother to the provinces, even if he makes international commitments."

A jury of five judges hears arguments from both sides as well as from interveners such as the provinces of New Brunswick and Ontario, which also fight against the federal carbon tax.

In total, 16 groups are involved in the case.

Ottawa is to present his page on Thursday. Saskatchewan has a chance to answer. Interlocutors for a carbon tax, including indigenous groups and environmentalists, will also speak.

The government of the Saskatchewan party argues that a carbon tax at federal level is unconstitutional because it is not applied equally across Canada and is under the jurisdiction of the provinces. Provinces that already have their own CO2 price plan are not subject to federal tax.

Saskatchewan is one of four provinces that have no plan for which Ottawa's gas will be available from April. New Brunswick, Ontario and Manitoba are the others.

The Federal Government's CO2 price starts at a minimum of $ 20 per tonne and will increase by $ 10 per year by 2022.

Stephanie Taylor, the Canadian press

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