The Supreme Court of Canada says the federal carbon tax is entirely constitutional.

The split decision upholds a pivotal part of the Liberal climate-change plan that accounts for at least one-third of the emissions Canada aims to cut over the next decade.

Chief Justice Richard Wagner says in the written ruling that climate change is a real and existential threat to Canada and the entire world, and evidence shows a price on pollution is a critical element to addressing it.

Canada implemented the Greenhouse Gas Pollution Pricing Act in 2019 setting a minimum price on carbon emissions in provinces which don’t have an equivalent provincial price, a law that was challenged by Saskatchewan, Ontario and Alberta.