REGINA -- The federal government argues it has jurisdiction to impose a carbon tax in Saskatchewan because climate change is a matter of national concern.
In written arguments filed with Saskatchewan's Court of Appeal this week, Ottawa says a failure by one province to reduce greenhouse gas emissions will hurt the rest of the country.
"Failure by one province to reduce GHG (greenhouse gas) emissions will harm other provinces and territories, harm Canada's relations with other countries, and impede international efforts to mitigate climate change," the factum says.
Saskatchewan has asked the court to rule whether the federal government's plan to force a carbon tax on the province is constitutional.
The province believes its own climate change plan, which doesn't include a carbon tax, is enough to reduce emissions.
Spokesman Jim Billington said Saskatchewan's constitutional lawyers are still analyzing the factum.
"We maintain that the carbon tax is unconstitutional because the federal government is applying a tax unevenly across the country based on their evaluation of provincial climate change plans, which they have no constitutional right to do," he said Wednesday in a statement.
Ottawa contends in the factum that there is no constitutional requirement for federal laws to operate equally throughout Canada.
The factum says emissions in Saskatchewan have increased by 10.9 per cent since 2005 and accounted for 10.8 per cent of the country's emissions in 2016.
The case won't be heard in court until at least the spring.
"We have a plan for a healthy environment and a stronger economy," federal Environment Minister Catherine McKenna said in a statement. "Because, at the end of the day, it's what we owe to our kids and grandkids."
Ontario has joined Saskatchewan's case as an intervener while also filing its own legal challenge.
Ottawa argues in the factum that the law isn't an intrusion into provincial jurisdiction. It says the act implements the "polluter pays" principle which is "firmly entrenched in environment law in Canada."
Keith Stewart, a spokesman for Greenpeace, said Ottawa is arguing that climate change is such a big deal for Canada as a whole that not allowing the federal government to bring in a carbon tax would affect it constitutional authority to provide peace, order and good government.
"If Saskatchewan wants to try and challenge that, they're pretty much going to have to try and deny the evidence presented by the intergovernmental panel on climate change, which every country in the world has signed on to," Stewart said.
Amir Attaran, a law professor at the Ecojustice Environment Law Clinic at the University of Ottawa, said Saskatchewan made a mistake by not acknowledging that the federal and provincial governments can co-operate to solve a problem such as climate change.
"That is, I think, going to kill them," he said.
The federal government had asked all provinces to put a minimum price on carbon emissions of $20 a tonne by Jan. 1.
Last week, Prime Minister Justin Trudeau detailed a plan to charge a carbon tax in Saskatchewan, Manitoba, Ontario and New Brunswick -- the four provinces that have refused to comply.
Ottawa plans to rebate the carbon tax money to residents of those provinces. It's estimated the average household payment in Saskatchewan will be $598.
On Tuesday, Saskatchewan introduced its own climate change law, which would amend current legislation.
Under the proposal, large emitters would be required to register with the province and could receive credits for reaching targets.
