Montana is among the states with a constitutional provision recognizing a right to environmental quality, in its case to a “clean and healthful environment.” Mont. Const. art. II, § 3. It further requires the state to take steps to “maintain and improve a clean and healthful environment.” Mont. Const. art. IX, § 1. On Dec. 18, 2024, the Montana Supreme Court decided in Held v. State of Montana that restrictions on state agencies’ ability to consider greenhouse gas emissions or climate impacts when evaluating the environmental impacts of state actions violate that constitutional right, and that private plaintiffs have standing to challenge those restrictions. 

Montana has an environmental review statute, the Montana Environmental Protection Act. It implements, in part, the constitutional obligation to take steps to maintain and to improve the clean and healthful environment by requiring state decisionmakers to take a hard look at environmental impacts of any action and to provide information for the public to understand those impacts.

As the Montana Supreme Court observed, based upon the trial below, climate change impacts of an action are sprawling. Also, because greenhouse gas emissions affect the climate worldwide, many impacts of a Montana emission will be felt elsewhere, and most of the impacts in Montana will be caused by emissions elsewhere. The Montana legislature, by statute, precluded MEPA reviews from considering greenhouse gas emissions or climate impacts, thereby streamlining reviews for projects such as coal mines, oil and gas development, and power production, etc.

A group of “youth plaintiffs” challenged that “MEPA Limitation” as unconstitutional. The case was tried to a judgment against the state, and the trial court issued a declaratory judgment in plaintiffs’ favor.

The Montana Supreme Court decided that the plaintiffs had standing to challenge the MEPA Limitation, even though the injury they alleged was the same alleged by many, if not all, Montanans; otherwise, no one could seek redress for the most consequential constitutional failures. Moreover, they had standing even though the injury they alleged was procedural. Nothing assures that if climate impacts are taken into account in Montana that the decisions of state agencies will be different or that greenhouse gas emissions will be lower. However, the plaintiffs have a right to require the state to take steps to maintain and to improve the clean and healthful environment and to provide the information to the public necessary to evaluate the state’s efforts. Finally, they had standing even though the contribution of Montana’s greenhouse gas emissions to climate impacts in Montana might be small relative to global greenhouse gas emissions.

The court went on to hold that the MEPA Limitation in fact violated the state constitution because it constrained state agencies from complying with their constitutional obligations. Note that Seven County Infrastructure Coal. v. Eagle County, Colorado, argued Dec. 10, 2024, in the U. S. Supreme Court, considered a related question: whether the National Environmental Policy Act allows an agency to consider environmental impacts outside the agency’s power to address.

This ruling could influence similar cases in states with analogous constitutional climate rights, such as Hawaii, New York, and Pennsylvania. Private litigation to force federal, state, and local attention to climate change have been ongoing for years. Climate advocates may cite this result in those contexts.