A group of Montana youth sued the State, arguing that its fossil fuel-based energy system contributes to climate change, violating their constitutional rights guaranteed under the Montana Constitution and the Public Trust Doctrine.  

Specifically, the plaintiffs filed claims based on experiencing past and ongoing injuries resulting from the State’s inaction on greenhouse gas emissions and climate change, including negative mental and physical health impacts. They also included injuries to spiritual, recreational and aesthetic interests, homes and property, economic security, Tribal and cultural traditions and happiness. 

Why it Matters for Public Health 

Montana is one of a handful of U.S. states whose constitutions include an affirmative right to a healthy environment. It is also one of the largest producers of coal in the United States and has abundant oil and gas reserves, all which contribute to greenhouse gas (GHG) emissions and climate change. State agencies are forbidden to evaluate GHG when evaluating requests for fossil fuel permits. Because GHGs produced from industries are known to pollute the air, water, and soil, the human health damages related to these pollutants should be part of agency decision-making.  As District Court Judge Kathy Seeley wrote in her decision, “Every additional ton of GHG (greenhouse gas) emissions exacerbates plaintiffs’ injuries and risks locking in irreversible climate injuries.” 

This case is the first time a U.S. state court has ruled against a government for violating a constitutional right based on climate change. 


On March 13, 2020, a group of 16 Montana youth, ages 5-22, filed a Complaint for Declaratory and Injunction Relief against the State of Montana. The Complaint specifically addressed the constitutionality of Montana’s State Energy Policy Act, an element of the Montana Environmental Policy Act (MEPA), which prohibits the State and its agents from considering the impacts of climate change or greenhouse gas emissions in their environmental reviews. 

During the trial, plaintiffs shared evidence of increasing carbon dioxide emissions that are leading to excessive heat, increases in wildfires and drought, and decreasing snowpack. The plaintiffs expressed that these changes in the environment are negatively impacting their physical and mental health. Members of Tribal communities testifying for the plaintiffs presented evidence that climate change affects ceremonies and traditional food sources. In addition, policy researchers, climate scientists, and a delegate to the 1972 Montana Constitutional Convention all testified in support of the plaintiffs. 

Attorneys for the Montana Attorney General’s office argued on behalf of the State. The state also provided witnesses who contested that even if Montana stopped producing carbon dioxide completely, it would not have a global effect because every country emits GHGs into the atmosphere.  

On August 14, 2023, Judge Seeley issued declaratory relief declaring that MEPA provisions are unconstitutional. The court concluded that “[b]y enacting and enforcing the MEPA Limitation,” the State failed to meet its affirmative duty under the state constitution. The court further held that the MEPA limitation does violate the State’s constitution and did not survive strict scrutiny because the State failed to present “any evidence of a compelling governmental interest for the provision.” 

This historic action will impact the state’s policies moving forward by, “invalidating statutes prohibiting analysis and remedies based on GHG emissions and climate impacts.”

Litigation Status (Open)

On September 27, 2023, the State appealed the ruling.

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