Canada’s carbon tax is unconstitutional, according to the Court of Appeal of Alberta.

In a 4-1 decision today (February 24), judges said the tax impinges on provincial affairs.

Chief Justice Catherine Fraser described the law as a “constitutional Trojan horse” and argued it violates provincial jurisdiction on issues concerning non-renewable resources.

“The Greenhouse Gas Pollution Pricing Act is a massive and unprecedented peacetime non-emergency invasion of Alberta’s and other provinces’ jurisdiction,” Fraser wrote.

“Buried within it are wide-ranging discretionary powers the federal government has reserved unto itself. Their final shape, substance and outer limits have not yet been revealed.”

Alberta Premier Jason Kenney responded warmly to the news and stated Alberta can take “meaningful action on climate change” without a tax “punishing Alberta families”.

"We urge the Trudeau government to respect the ruling of the court, and scrap their carbon tax immediately,” he wrote on Twitter.

Previously, appeals courts in Ontario and Saskatchewan sided with the federal government, ruling Ottawa does have the power to tax air pollution.

Alberta’s top court is the first to issue a judgement against the tax.

The Supreme Court of Canada is now scheduled to receive the case next month.