Clifford Chance

In the first constitutional climate case of its kind to reach trial in the United States, a state district court in Montana ruled in favor of sixteen young Montanans, who invoked their right to a clean and healthful environment under Montana's state constitution to challenge state law limits on state agencies' consideration of climate impacts in permitting decisions.

In March 2020, sixteen young plaintiffs (now aged five to twenty-two) filed a complaint for declaratory and injunctive relief against the state of Montana, its then-Governor, and various state entities. The complaint in Held v. Montana challenged the constitutionality of Montana's State Energy Policy, which plaintiffs alleged promoted the use of fossil fuels. Plaintiffs also challenged a 2011 provision of the Montana Environmental Policy Act ("MEPA Limitation"), which prohibited the State and its agencies from considering the impacts of greenhouse gas emissions in their environmental reviews of proposed energy projects. A 2023 amendment to that provision in HB 971 expressly provided that agencies were prohibited from considering "an evaluation of greenhouse gas (GHG) emissions and corresponding impacts to the climate in the state or beyond the state's borders."

The plaintiffs argued that Montana's State Energy Policy and MEPA Limitation caused increased levels of greenhouse gas emissions, contributing to climate change and the depletion of Montana's natural resources. Plaintiffs claimed that this violated their fundamental right under the state constitution to "a clean and healthful environment" (Mont. Const. Art. II, § 3) and the state's obligation to "maintain and improve a clean and healthful environment in Montana for present and future generations." (Mont. Const. Art. IX, § 1).

The case overcame two major obstacles to reach trial. First, in August 2021, the district court ruled on a motion to dismiss that the plaintiffs had standing to sue, finding that the plaintiffs demonstrated a "genuine factual dispute" as to whether defendants' actions and the underlying state policy were a substantial factor in the plaintiffs' injuries, and that they sufficiently alleged that Montana was responsible for "a significant amount" of overall greenhouse gas emissions in the US. Although the court dismissed on political question grounds the plaintiffs' demand for broad injunctive relief, the court agreed that it could grant declaratory relief without imposing an injunctive remedy.

Second, in 2023 defendants sought to dismiss the case as moot due to intervening legislative developments, including the repeal of the State Energy Policy in March 2023. In May 2023, the district court agreed that the repeal mooted plaintiffs' challenge to the Energy Policy. However, the court denied defendants' motion for summary judgment on the MEPA claims, paving the way for those claims to proceed to trial.

Trial commenced in June 2023. Several individual plaintiffs testified about how climate change was impacting them, and the plaintiffs presented expert testimony regarding the science of global warming and its links to GHG emissions, including from Montana. The defendants in turn did not dispute the scientific basis for the claim that human-induced GHG emissions cause climate change or that climate change was causing harm to the plaintiffs. Instead, the defense argued that state agencies only implement the law and that plaintiffs' proper remedy was through the legislature, not the courts. The defense also argued that Montana's contribution to global greenhouse gas emissions was so small that, even if the law in question were altered or overturned, there would be “no meaningful impact or appreciable effect” on climate change.

In ruling for the plaintiffs, District Judge Seeley held that residents of Montana have a "fundamental constitutional right to a clean and healthful environment, which includes climate as part of the environmental life-support system." She further held that the MEPA Limitation violated this constitutional right, and that Montana's failure to consider emissions and climate change in its environmental reviews had caused impacts to the state's environment as well as disproportionate harm to its youth.

In addition, Judge Seely held that a provision of SB 557—signed into law on the eve of trial and making it more difficult for groups to challenge environmental review under MEPA—was unconstitutional.

The plaintiffs' trial victory ends this stage of the litigation, but the state Attorney General's Office has said that it will appeal the decision to the Montana Supreme Court.

Looking forward across the US climate litigation landscape, Held v. Montana is a first. Significantly, it is the first case to hold that the failure of a state government to account for emissions giving rise to or exacerbating climate change violates a state constitutional right to a healthy environment. This result will doubtless energize other plaintiffs, as a handful of other states have constitutional rights to a healthy environment—Hawaii (Art. XI, § 9), Illinois (Art. XI), Massachusetts (Art. XCVII) New York (Art. I, § 19), and Pennsylvania (Art. I, § 27)—and other states are considering or have introduced such amendments. But these rights may have different scopes or effects, and these states may not have provisions comparable to the now-invalidated MEPA Limitation. The immediate impact of the decision therefore will be limited to Montana and the specific rule set forth in the MEPA Limitation and will not affect other state litigation, including in states in which a right to a healthy environment exists.

The case is also the first US-based youth-led climate lawsuit to successfully argue that state failures disproportionately harm young people. For this reason, attention will now turn to another, youth-led lawsuit, Juliana v. United States, which has a long history in federal court in Oregon. In that case, twenty-one young plaintiffs have sued the US federal government, alleging that its failure to act on climate change despite knowledge of its impacts violates their rights under the U.S. Constitution. The Juliana plaintiffs face substantial additional hurdles, however, as the US Constitution does not include the same express right to a healthy environment as the Montana Constitution, and a federal court of appeals has already held previously that the plaintiffs lack standing to pursue their claims because their proposed remedies should be addressed by the political branches and not by the courts.