Reference re Greenhouse Gas Pollution Pricing Act

In Reference re Greenhouse Gas Pollution Pricing Act 2021 SCC 11, the Supreme Court of Canada ruled on 25 March 2021 that the federal carbon pricing law is constitutional.

Background
In response to Canada's 2016 ratification of the Paris Agreement which set greenhouse gas emission reduction targets, the Canadian federal government under Prime Minister Justin Trudeau passed the Greenhouse Gas Pollution Pricing Act (GHGPPA), which came into effect on 21 June 2018, establishing national standards for a carbon price.

Procedural history
The province of Saskatchewan, under Premier Scott Moe, referred a reference question to the Court of Appeal for Saskatchewan regarding the law's constitutionality. On 3 May 2019 the Court of Appeal ruled in favour of the federal government, concluding that, GHGPPA is "not unconstitutional either in whole or in part"  and was a legitimate exercise of federal jurisdiction under the peace, order, and good government" (POGG) branch of the constitution (Justices Ottenbreit and Caldwell dissenting). Saskatchewan appealed this decision to the Supreme Court of Canada on 31 May 2019.

The province of Ontario, under the premiership of Doug Ford, also referred a reference question to the Court of Appeal for Ontario, seeking a finding that the GGHPPA was unconstitutional. On 28 June 28 2019, the ONCA issued its advisory opinion, finding the law constitutionally valid (Justice Huscroft dissenting). Ontario was granted leave to appeal this decision to the Supreme Court of Canada.

The province of Alberta, led by then-Premier Jason Kenney, referred its own reference question to the Court of Appeal of Alberta on June 20, 2019. On February 24, 2020, that court issued an opinion which found the GHGPPA unconstitutional (Justice Feehan dissenting). The Attorney General of British Columbia appealed this decision to the SCC.

Breakdown of the decision
The majority found the Act to be constitutional including Chief Justice Richard Wagner and Justices Rosalie Silberman Abella, Michael J. Moldaver, Andromache Karakatsanis, Sheilah L. Martin, and Nicholas Kasirer.

Justices Russell Brown and Malcolm Rowe dissented and Justice Suzanne Côté dissented in part.

Climate change is real
The Supreme Court said that "all of the parties agree that global climate change is real. It's caused by greenhouse gas emissions resulting from human activities and it poses a grave threat to the future of humanity."