The Alaska LNG Project would involve the construction of a gas treatment plant on the state’s North Slope, an 800-mile pipeline and liquefaction plant on the Kenai Peninsula which would prepare the gas for export to Asia.

“[Y]outh plaintiffs are uniquely vulnerable to and disproportionately injured by the climate harms that would result from the Alaska LNG Project,” the suit says.

In an unusual move in 2014, Alaska passed legislation amending multiple state laws to direct the state to see the project through.

The challengers, aged 11 to 22, argue that the proposal – and that legislation in particular – violates two sections of the Alaska constitution: the right to protected natural resources for “current and future generations”, and the right to be free from government infringement on life, liberty and property.

“The acceleration of climate change that this project will bring will affect what the land provides and brings to my culture,” said Summer Sagoonick, the 22-year-old lead plaintiff in the case and a member the Iñupiaq tribe. “I am counting on the courts to protect my rights.”

The Alaska attorney general, Treg Taylor, said his office would be reviewing the lawsuit carefully and called it a “misguided effort.”

“On its face, we can see that it is an attempt to block the development of Alaska’s natural gas reserves based on a purported environmental safety rationale,” he said. He added that Alaska was experiencing a shortage of gas, which he claimed was a “clean fuel”. And he said if the state did not develop gas, another place probably would, “without stringent standards to protect the environment.”

The case was filed by Our Children’s Trust, the non-profit law firm that won a groundbreaking climate victory on behalf of young Montanans last year.

Global warming is already taking a toll on the young Alaskans, the lawsuit says, by “interfering with their natural development, disrupting their cultural traditions and identities, and limiting their access to the natural resources on which they rely.”

Fish and other species that the plaintiffs eat are dying due to changes in the climate. More frequent and severe wildfires are threatening the young people’s homes and exposing them to dangerous pollution from smoke. And the knowledge of the threat of the climate crisis is taking a toll on their health, the complaint says, among other impacts.

Those effects have been particularly harsh for Native Alaskan youth, the complaint says. That includes Sagoonick, who resides in the village of Unalakleet, which is vulnerable to climate-induced flooding, rapid permafrost thawing and severe coastal erosion.

“We’re already seeing huge impacts to our ability to provide for our subsistence because of climate change,” she said.

Sagoonick learned to fish, hunt and gather when she was young; she relies on local subsistence foods, including salmon and other fish, seal, duck and cranberries, for the vast majority of her diet, the lawsuit says.

“As our water warms and the land erodes, it poses a threat to our nourishment and our cultural practices,” Sagoonick said.

Tim Fitzpatrick of the Alaska Gasline Development Corporation said: “AGDC is directed by Alaska statute to commercialize North Slope natural gas because of the substantial environmental, economic and energy security benefits it unlocks for our state.” He added that the project had “withstood intensive environmental scrutiny by two successive administrations because of its obvious and abundant benefits”.

Four of the plaintiffs, including Sagoonick, were also part of a 2017 Our Children’s Trust lawsuit against Alaska that argued the the state’s promotion of fossil fuels in general violated the challengers’ state constitutional rights.

In 2022, the Alaska supreme court dismissed that case in a 3-2 decision. But the two dissenting justices said under Alaska’s constitution, the “right to a livable climate” is “arguably the bare minimum” when it comes to the rights enshrined in the state constitution.

“They are the only two justices from the Alaska supreme court to address this question of whether Alaska’s constitution guarantees the right to a climate system that sustains human life,” Andrew Welle, senior staff attorney for Our Children’s Trust and counsel for the Alaska plaintiffs. “So we’re seeking for the full court to decide that same issue.”

Though it did not set precedent, Welle said the decision is a “a strong indication”.

The complaint marks the first time Our Children’s Trust is challenging a specific fossil fuel project, rather than a government’s overall support of fossil fuels. The state of Alaska is named as a defendant, as is the Alaska Gasline Development Corporation and that corporation’s president, Frank Richards.

The youth plaintiffs are hoping the court issues an order prohibiting the state from moving forward with the project. They are also seeking to set precedent recognizing that fossil fuel infrastructure violates the plaintiffs’ constitutional rights.

“That is the first step to securing broader vision of climate justice for Alaska’s youth, as that can be built upon in future cases and enforcement actions,” said Welle.

Earlier this year, Montana’s supreme court upheld a groundbreaking decision in a case filed by Our Children’s Trust, requiring state regulators to consider the climate crisis before approving permits for fossil fuel development. The state has appealed that decision, and on Tuesday, the court said it would hear oral arguments this coming July.

Our Children’s Trust also has pending state lawsuits in Hawaii – which will go to trial in June – as well in Florida, Utah and Virginia. On Monday, it filed an amended complaint against the federal government on behalf of California youth.

A federal appeals court this month granted the Biden administration’s request to strike down a landmark federal case from Our Children’s Trust.