The Saskatchewan Court of Appeal has ruled the federal government's carbon tax is constitutional.
A 155-page decision was handed down Friday afternoon.
"Ontario doesn't need a carbon tax to fight climate change", said Rod Phillips, Minister of the Environment, Conservation and Parks.
"Pollution doesn't know any borders".
Mr Trudeau, citing worldwide commitments on global warming, four years ago campaigned on a promise to introduce a plan to fight climate change, and on April 1, he slapped a federal tax on the four provinces that had refused to introduce their own carbon-reduction plans.
We believe that our strong plan makes a federal carbon tax redundant and that a consumer-punishing retail carbon tax - whether imposed by the NDP or by Justin Trudeau - is the wrong way to go.
The PBO calculates source revenue related to the tax will be 90 per cent fuel-based reaping $2.63 billion this year; $6.21 billion by 2021. "It's just another cash grab which is hurting already overtaxed Canadians". The court also concluded that carbon pricing is an element of reducing greenhouse gas emissions and therefore in fighting climate change internationally. Ontario will continue to protect what matters most and stand up for the people by opposing the federal government's carbon tax, which threatens the province's jobs and makes life less affordable for families, students, seniors and communities.
He also said the environment "is not a legislative subject matter that has been assigned to either Parliament or the provincial legislatures under the Constitution Act".
Ontario argued that the provinces, not the federal government, have the primary responsibility to regulate greenhouse gas emissions and that the regulatory charges the act seeks to impose are in fact unconstitutional disguised taxation.
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"The notion that national benchmarks are required merely speaks of a federal dissatisfaction with provincial policy and a desire to impose federal policies on those provinces", they wrote.
Among them was Sydney Chadwick, a Grade 12 student at Lumsden High School who helped organize the first Regina student climate strike in March.
Manitoba recently filed papers in Federal Court for its challenge, while Ontario was in court last month to argue its case and is waiting for the outcome. "That's Game 1. We still have other games to play", he said.
"Ultimately this (question) will be decided in this fall's election at the ballot box".
New Brunswick Premier Blaine Higgs promised to join what he said will "almost certainly" be an appeal to the Supreme Court for its opinion. "New Brunswick remains committed to doing its part to reduce carbon emissions".
Both provinces then instituted a court challenge against the federal legislation.
Under the Made-in-Manitoba plan, the province was to impose a price of $25 per tonne that would not rise which was rejected by the federal government.
Justice Minister Cliff Cullen said Manitoba's case is different because the province had planned its own, lower carbon tax, but it was rejected by Ottawa.