Limits of Climate Change Suits Against the Government: Mathur v. Ontario Decision

The Superior Court of Justice has now released its decision in Mathur v. Ontario, a case we wrote about earlier this year and which is now a further example of an unsuccessful claim against a government in respect of climate change. The lawsuit involved an application brought by seven Ontario youth claiming, among other things, that Ontario’s legislated targets and plans for reducing greenhouse gas (GHG) emissions were not stringent enough to combat climate change and, therefore, infringed their constitutional Charter rights. Although the Court had sympathy for many of the applicants’ arguments and held that most of the issues raised by the applicants were justiciable by the Court, it nevertheless dismissed the application as it found no Charter violations.


The application concerned provincial legislation passed in 2016 that implemented a cap and trade program for GHG emissions, and subsequent legislation, the Cap and Trade Cancellation Act, 2018 (CTCA) passed by the newly elected provincial government that repealed the 2016 legislation and set out a plan to meet a more lenient target for GHG emission reductions. In effect, the lawsuit sought to force the government to set more stringent targets for GHG emissions. To support their lawsuit, the applicants tendered expert evidence regarding the impacts of climate change and what they alleged was Canada’s and Ontario’s “fair share” of future carbon emissions.


With respect to allegations that the government’s actions were unconstitutional, the Court held that the applicants had challenged specific state action and legislation (i.e. the CTCA and the subsequent lower GHG targets set by the government) and, therefore, the issues raised regarding Charter violations were justiciable – i.e., that the issues were suitable for judicial determination.

The only issue the Court did not find justiciable was the applicants’ argument that the Court should determine Canada and Ontario’s “fair share” of future worldwide carbon emissions. The Court noted there is more than one way to determine carbon budgets and allocation, and “this issue does not have a sufficient legal component to allow this Court to choose among competing approaches.”

Charter Claims

The Court addressed various Charter arguments, primarily related to whether there were violations of Sections 7 and 15. Notable aspects of the decision were as follows.

The Court quickly rejected the applicants’ argument that the government’s action to repeal the cap and trade program and enact the subsequent CTCA was unconstitutional. It concluded that a “mere change in the law cannot be the basis for a Charter violation”.

The applicants alleged that the CTCA violated section 7 of the Charter, i.e., their right to life, liberty and security of the person and the right not to be deprived thereof except in accordance with the principles of fundamental justice. The Court characterized the applicants’ claims as alleging the government was not doing enough to protect their right to life, liberty and security of the person, but the Court ultimately held that the applicants had not demonstrated any deprivation was contrary to the principles of fundamental justice. The Court’s analysis about causation was especially notable, as the Court rejected the government’s argument that there was no causal connection between the government’s target for reducing GHC and mitigating the effect of climate change.

The Court found that by not taking steps to reduce GHG emissions in Ontario further, the Ontario government was contributing to an increase in the risk of death, and that while Ontario’s contributions to global warming “may be numerically small, it is real, measurable and not speculative.” The Court also rejected that a so-called “societal preservation principle” was a principle of fundamental justice protected by section 7 of the Charter. It concluded that while “societal preservation may be an important public policy and/or state interest, it is not a normative legal principle or a basic tenet of our legal system.”

The applicants also alleged that the CTCA violated section 15 of the Charter, which provides that every individual is equal before and under the law and has the right to the equal protection and equal benefit of the law. Their argument was based largely on evidence that climate change would disproportionately impact them, as younger people who would be exposed to the worsening effects of climate change over time. The Court stated that section 15 “does not impose a positive obligation on the state to remedy social inequalities or enact remedial obligation...” and held that the applicants had not established a violation of section 15 of the Charter.

Closing Considerations

To date, litigants in Canada have not been successful in challenging alleged government action or inaction on climate change-related matters. Nevertheless, litigants continue to look for avenues to impose responsibility for climate change and to require governments to take more robust actions to mitigate GHG emissions. The applicants have already announced they will appeal the Court’s decision. Goodmans will be watching with interest as the case moves through to an appeal.

For more information concerning climate change or how it may impact businesses, please contact any member of our Dispute Resolution or Environmental groups.