The Montana District Court has handed down a potentially landmark judgment in climate litigation in which the State’s constitutional right to a clean and healthy environment was used as the basis to challenge its energy policy.

As we reported in our most recent bi-annual Climate Litigation update here, in June 2023, the trial took place in the novel climate lawsuit  brought by a group of sixteen children and young people (aged 5 to 21) against the State of Montana for its endorsement of an energy system allegedly driven by fossil fuels. The Claimants claimed that the State’s energy policy is responsible for the effects of climate change (particularly drought and wildfires) that are affecting their lives. The policy therefore violates their constitutional right to a clean and healthy environment, as enshrined in the Montana Constitution. The Claimants focused on the State law forbidding the consideration of climate impact during environmental reviews.

On 14 August 2023, based on the extensive scientific evidence presented at the trial (covering issues such as climate projections, the impact of climate change on the psychological and physical health of young people, the particular harm experienced by the Claimants and the extent to which the Defendants’ actions contributed to such harm suffered), Judge Kathy Seeley ruled in the Claimants’ favour, setting a potentially powerful precedent for climate litigation in the US Courts.

Key points from the judgment

  • With regard to proving injury, the Court held that the Claimants’ mental health injuries directly resulting from State inaction or counterproductive action on climate change did not establish a cognizable injury on their own. However, their mental health injuries stemming from the effects of climate change on Montana's environment, feelings like loss, despair, and anxiety, were cognizable injuries. The judge also held that the Claimants are disproportionately harmed by fossil fuel pollution and the harm they suffered as young people is distinguishable from the public generally.
  • The Claimants were successful in establishing causation between the State’s disregard of greenhouse gas (GHG) emissions and climate change and their proven injuries. The Court held that the State’s authorisation of fossil fuel activities without proven analysis of GHG emissions and climate impacts has caused, and continues to exacerbate, climate change caused by human activities. This is despite the State’s obligation to protect Montana’s environment and natural resources and the health of the State’s inhabitants.
  • In 2020, when the case was filed by the Claimants, the Montana Energy Policy Act (MEPA) stated that actual or potential environmental impacts that are regional, national or global in nature could not be considered in governmental reviews of new energy related projects. This had the effect of limiting what has been found to be necessary consideration of climate change. 
  • The 2023 version of this MEPA Limitation, which had been made increasingly explicit in its exclusion of the consideration of climate change impacts, was held to be subject to strict scrutiny because it implicates the Claimants’ fundamental and constitutional right to a clean and healthy environment. 
  • The MEPA Limitation did not pass such scrutiny as the State failed to show that it served a compelling governmental interest. The Court therefore declared this State law to be unconstitutional. Injunctive relief prohibiting the State from acting in accordance with such statutes was appropriate. 


For Montana itself, the ruling means that the State is now legally required to factor the climate impacts of proposed energy projects into the decision-making process. More broadly, although not a binding precedent across other States, if this decision survives future challenges, including the planned appeal by the Montanan State, it will likely influence other similar climate cases. There are a number of cases currently under way in States including Hawaii, Illinois, Pennsylvania and New York, where the State Constitutions also recognise the people’s right to a clean and healthy environment. As a result, the future of this decision of the Montana District Court will be closely watched by climate activists and States alike.



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