Plaintiff-appellants' memo of fact and law

Two houses of the Wet’suwet’en indigenous group filed a legal challenge on February 10, 2020 alleging that the Canadian government's approach to climate change has violated their constitutional and human rights. 

According to the complaint, plaintiffs Misdi Yikh and Sa Yikh are each a House group under Wet’suwet’en indigenous law, and comprise the Fireweed Clan. The plaintiff Lho’imggin is the dinize’, or Head Chief, of Misdzi Yikh and the plaintiff Smogilhgim is the dini ze’ of Sa Yikh; each speaks for his House. 

The plaintiff complaint allege that Canada failed to meet its international commitments to reduce greenhouse gases, including those made at the 1988 International Conference on the Changing Atmosphere and under the 1992 United Nations Framework Convention on Climate Change, the 1998 Kyoto Protocol, the 2009 Copenhagen Accord, the 2010 Cancun Agreement and the 2015 Paris Agreement. Plaintiffs further claim that Canada's Nationally Determined Contribution under the Paris Agreement—to reduce annual greenhouse gas emissions by 30% below 2005 levels by 2030—is insufficient to meet its commitments to hold global warming below 2 degrees Celsius and pursue efforts to keep warming to 1.5 degrees. Moreover, according to plaintiffs, Canada appears unlikely to meet its Nationally Determined Contribution.  Finally, plaintiffs argue that Canada has failed to use discretionary decision-making power under its environmental assessment legislation to withhold approval of greenhouse gas emitting projects—in particular liquefied natural gas exports facilities—to help bring Canada's trajectory in line with the Paris Agreement targets.

Plaintiffs contend that they have experienced significant warming effects on their territories and expect to experience negative health impacts due to climate change. They further assert that Canada's historical treatment of indigenous leaders and ongoing racial discrimination exacerbate the psychological and social trauma caused by climate change. Their claims arise principally under Section 91 of the Constitution Act, 1867 (duty to make laws for the peace, order and good government of Canada); Section 7 of the Charter of Rights and Freedoms (right to life, liberty and security of person); and Section 15(1) of the Charter of Rights and Freedoms (equality before the law).

Plaintiffs seek declaratory relief; an order requiring the government to amend each of its environmental assessment statutes that apply to extant high greenhouse gas emitting projects to allow project approval to be canceled if Canada will be unable to keep its Paris Agreement commitments or considers climate change to be a national emergency; and an order requiring the government to complete an annual account of its cumulative greenhouse gas emissions in a format that allows comparison to Canada's carbon budget. 

The defendant Canada filed a motion to strike on July 28, 2020, and plaintiffs responded to the motion on September 10, 2020.

On November 16, 2020, the Federal Court granted the motion to strike without leave to amend on the grounds that the case was not justiciable, had no reasonable cause of action, and the remedies were not legally available. The Court found that the case was not justiciable because it did not have a sufficient legal component to anchor the analysis. The Court wrote, "[t]he issue of climate change, while undoubtedly important, is inherently political, not legal, and is of the realm of the executive and legislative branches of government." The Court further found that because plaintiffs did not reference specific sections of laws that cause specific breaches of Charter rights, their claims presented no reasonable cause of action. With regard to remedies, the Court found that the multifaceted problem of climate change would make judicial supervision meaningless, and therefore the Court could not take on a supervisory role to ensure adequate laws were passed. 

On December 10, 2020, plaintiffs appealed the Federal Court judge's dismissal to the Federal Court of Appeal, and on April 30, 2021, they filed their memorandum of fact and law. Canada responded with their memo of fact on law filed on June 28, 2021. 

The appeal was heard on February 14 and 15, 2023, concurrently with La Rose v. Her Majesty the Queen. On appeal, Justice Rennie, Justice Laskin, and Justice Leblanc agreed to strike the case. However, the court noted that the section 7 Charter claims were justiciable had it not been for “the expansive and diffuse scope of the pleadings . . . framed [to be] incompatible with constitutional adjudication.” More specifically, Justice Rennie noted that the plaintiffs' approach of arguing the cumulative effects of the law as breaching the constitution would require an analysis of “each and every law, regulation and Order in Council which results in GHG emissions,” which is practically unfeasible. In striking the case, the court granted the appellants in both cases to amend their pleadings. Following the decision, the plaintiffs submitted an Amended Claim on August 26, 2024. A Further Amended Claim was filed again on December 16, 2024.

On September 26, 2025, Justice McVeigh of the Federal Court reviewed and struck the Further Amended Claim while granting the plaintiffs a leave to amend their Further Amended Statement of Claim. The court focused on two aspects of the newest claims: (i) a novel cause of action based on customary international law; and (ii) the amended section 7 Charter claim. 

On the first aspect, more specifically, the plaintiffs claimed that Canada failed to keep pace with its 2030 Temperature Commitment and Nationally Determined Contribution under the multi-national Paris Agreement, which has started to cause detrimental effects of climate change on their territories. In reviewing this claim, the Court, concerning the recent International Court of Justice (ICJ) Advisory Opinion [2025] ICJ Rep 456, clarified that although the Opinion is not binding in Canadian courts, it “can influence how courts interpret domestic laws, particularly in relation to constitutional rights and international obligations.” The court clarified that Constitutional challenges to Canadian domestic law can be brought in Canadian courts, while it lacks the jurisdiction to directly adjudicate on an infringement under the Paris Agreement itself. The court also pointed out that because “customary international law is automatically incorporated into domestic law even in the absence of legislation” and “novel but arguable claims must be allowed to proceed to trial,” the plaintiffs can try bringing a common law (tort) case by establishing that there is an enforceable customary international law at issue.

On the second aspect, the court held that the Further Amended Claim, while it "have now produced numerous laws and regulations that [plaintiffs] identify as breaching Canada’s international commitment," it "still does not narrowly identify a specific law or set of provisions for constitutional review." The court characterized the new section 7 Charter claim as "reasonably arguable but insufficiently narrow."

Lho’imggin et al. v. Her Majesty the Queen

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Lho’imggin et al. v. Her Majesty the Queen - Other

Filed

Canada

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An aim to achieve a quantifiable outcome within a given time-frame, set by an institution such as a national government.

Policy instruments are techniques or tools used by governing authorities to promote certain policies in order to achieve predetermined goals. Put simply, instruments are how a government tries to achieve its goals, with this taxonomy being focused on national policy instruments.

Risk is the potential for adverse consequences resulting from the dynamic interplay between (climate-related) hazards, exposure, and vulnerability of affected human or ecological systems.

Groups  of people who are adversely affected by climate change or the response to it

A set of principles, processes, and practices that build economic and political power to shift from an extractive economy to a regenerative economy.

Justice is the ethical and political framework that addresses fairness, including issues of responsibility, rights, and structural inequity.

Renewable energy means all forms of energy produced from renewable sources in a sustainable manner.

Fossil fuel is a generic term for non-renewable energy sources such as coal, fossil gas, and oil (including crude oil, and petroleum products), that can be used for electricity and heat generation. Fossil fuels are hydrocarbons formed from pressurised and heated organic material buried over millions of years.

Molecules in the atmosphere that play a key role in the greenhouse effect by trapping heat radiating from Earth’s surface.

Area of the economy in which actors engage in identical or related activities.

In human systems, the process of adjustment to actual or expected climate change and its effects, in order to moderate harm, increase resilience or exploit beneficial opportunities. In natural systems, the process of adjustment to actual climate change and its effects; human intervention may facilitate adjustment to expected climate change and its effects.

The management and allocation of funds, assets and investments to meet various objectives

People who are less able to respond to the effects of climate change due to having limited financial or physical assets

A ban is a legal action that prevents the sale or supply of a product or service, or that recalls a product from the market. Examples are bans on SF6, greenwashing, fossil fuel advertisement or single-use plastics.

Hot temperature extremes are daily maximum temperatures  that were exceeded on average once in a decade or once in 50 years, and includes heatwaves.

The release of heat-trapping gases, primarily from human activities such as burning fossil fuels, agriculture and industry.

Risks to the ecosystem health of the marine environment, including ocean warming, ocean acidification, and ocean deoxygenation, harming biodiversity, species health, ecosystem services, and coastal community livelihoods.

Extreme weather refers to events where a weather variable exceeds (or falls below) a threshold. Meaning it is significantly different from the average or usual weather pattern.

Terrestrial means "of the earth" and relates to the risks to ecological system that includes all living organisms and their interactions within land-based environments, such as forests, grasslands, and deserts.

Air pollution involves harmful contaminants in the air, affecting both indoor and outdoor environments. It can lead to health issues like respiratory diseases and heart problems, and climate impacts such as global warming. Pollutants can damage plants, trees, habitats, and water bodies like rivers and lakes.

Social protection systems consist of policies that help people manage social risks in order to prevent poverty and maintain decent incomes and living standards

Fossil gas, commonly known as natural gas, is a fossil fuel consisting chiefly of methane with smaller amounts of other hydrocarbons and trace gases, found in underground deposits.

People with different national or cultural traditions from the dominant population

Social and cultural groups that share collective ancestral ties to the lands and natural resources where they live, occupy or from which they have been displaced

People whose health, both mental and physical, makes them more vulnerable to the effects of climate change

People who have left their homes, whether through force, voluntarily, or a mixture of both

The activities of industries involved in the production, distribution, and sale of energy, including electricity, gas, and renewables.

This sector involves activities to move goods and people, alongside the storage of products.

This sector creates and distributes information and entertainment through television, radio, print, and digital platforms.

This sector involves activities that impart knowledge and skills to individuals, including formal schooling, vocational training and educational support.

Activities of government agencies and institutions that provide public services, enforce laws and manage public resources.

Activities involving the catching, processing, and selling of fish for food, recreation, and industry.

Slow onset events evolve gradually from incremental changes over many years or from increased frequency or intensity of recurring events. As defined in the Cancun Adaptation Framework (2010), slow onset events include risks and impacts from rising temperatures, desertification, biodiversity loss, land and forest degradation, glacial retreat, ocean acidification, sea level rise, and salinization.

Lho’imggin et al. v. Her Majesty the Queen - Other

Policy instrument

Risk

Impacted group

Just transition

Fossil fuel

Greenhouse gas

Economic sector