The court rejected federal arguments that reducing greenhouse gases met the legal test of being a national concern.
“Almost every aspect of the provinces’ development and management of their natural resources … would be subject to federal regulation.”
It noted health care, minimum wages and justice are all national concerns but are administered by the provinces.
The court ruled that, for something to be a national concern within federal jurisdiction, it would have to be beyond the scope of provincial powers.
Monday’s decision is the first to side with a province against the federal government.The Alberta judgment notwithstanding, the issue will be settled this spring when Saskatchewan's appeal is heard by the Supreme Court of Canada.
Courts in both Saskatchewan and Ontario upheld the federal levy last year.