appeal

Mathur, et al. v. His Majesty the King in Right of Ontario - appeal

Litigation

Sabin

Sabin Litigation

complaint

Mathur, et al. v. His Majesty the King in Right of Ontario - complaint

reply

Mathur, et al. v. His Majesty the King in Right of Ontario - reply

decision

Mathur, et al. v. His Majesty the King in Right of Ontario - decision

judgment

Mathur, et al. v. His Majesty the King in Right of Ontario - judgment

Filing Year For Action

The Cap and Trade Cancellation Act (CTCA) was enacted by the province of Ontario in 2018. It repealed the Climate Change Mitigation and Low-Carbon Economy Act, which had established an emission reduction target of 37% below 2005 levels by 2030 in the province, and implemented a revised target of 30% below 2005 levels by 2030. In response, Ecojustice assisted seven youth environmental activists who filed an application against Ontario, contesting the constitutionality of CTCA. The Applicants argued that the revised target did not adequately address the risks associated with climate change, thereby violating the rights of Ontario youth and future generations as protected by sections 7 and 15 of the Canadian Charter of Rights and Freedoms. They contended that their section 7 right to life, liberty, and security of the person was infringed due to the perilous and existential threats posed by climate change to the lives and well-being of Ontarians. The Applicants maintained that their section 15 right to equality was violated because the revised target created a distinction based on age, imposing a greater burden on younger Ontarians who would endure the long-term impacts of climate change. They sought a declaration that the revised target was unconstitutional and an order requiring Ontario to establish a revised emissions target grounded in scientific principles, consistent with Ontario’s commitments under the Paris Agreement.

On April 15, 2020, Ontario filed a motion seeking to dismiss the case on the grounds that the claim was not justiciable. Ontario argued that determining emissions reductions was inherently political and thus unsuitable for judicial review. On November 12, 2020, Justice Brown of the Ontario Superior Court denied the motion, finding that it was not immediately apparent that the revised target would be immune from court scrutiny. 

In September 2022, the lawsuit proceeded to a hearing on its merits before the Ontario Superior Court. On April 14, 2023, Justice Vermette of the Ontario Superior Court determined that while the Applicants’ claim was justiciable, there was no violation of the Applicants’ sections 7 and 15 Charter rights. Regarding section 7 of the Charter, Justice Vermette found that the province’s revised target for reducing greenhouse gas (GHG) emissions was not arbitrary, as it was linked to the objective of GHG reduction under the CTCA. With respect to section 15 of the Charter, Justice Vermette concluded that the provision did not impose a positive obligation on the provincial government to take any specific actions to combat climate change. The Ontario Superior Court, therefore, dismissed the case. 

The applicants appealed to the Court of Appeal for Ontario in May 2023. On October 17, 2024, the Court of Appeal for Ontario released its decision unanimously in favor of the appeal. The Court found that the applicants’ case was not a positive rights case but rather a negative rights case because they were not requesting that Ontario implement specific climate change actions. Instead, they contended that the greenhouse gas emissions targets set by the Minister under the CTCA violated their Charter rights. In other words, by enacting the CTCA, the Ontario government voluntarily assumed a positive statutory obligation to combat climate change in a way that complies with the Charter. Given the lack of a complete evidentiary record, the ONCA declined to determine the applicants’ case on its merits and remitted the application for further consideration by the lower court.

On December 16, 2024, the Ontario government filed an application for leave to appeal the case to the Supreme Court of Canada. On May 1, 2025, the Supreme Court rejected the appeal. The case will now return to the Ontario Superior Court of Justice for a new trial. 

Mathur, et al. v. His Majesty the King in Right of Ontario