A landmark judgement in the US state of Montana has seen its Environmental Policy Act ruled unconstitutional because it does not consider the climate impacts of fossil fuel projects, setting an important precedent for similar cases nationwide.

After three years in the courts, the case brought by 16 youth, each of whom described the impacts of climate change on their lives, said the law violated their state constitutional rights to a clean and healthy environment.

"This court ruling is a step toward climate justice," said Delta Merner, lead scientist at the Science Hub for Climate Litigation at the Union of Concerned Scientists, in a statement on Monday. "I'm greatly encouraged to see a judge uphold people's constitutional rights to a healthy environment.

"Whether it's governments, fossil fuel companies or industry trade groups — holding polluters and their enablers accountable is a critical piece of meaningful climate action. The case in Montana is a clear sign that seeking climate justice through the courts is a viable and powerful strategy," she added.

The judgement echoes a successful 2021 case brought by young people against the German government over a climate law which, they argued, is so inadequate it violates their fundamental right to a humane future. The German Constitutional Court ruled that the federal government had to update its 2030 emission reduction targets.  

Two years later, the German government is again being dragged into court for failure to meet its climate goals.

'Duty of care' to protect future generations

While the Montana case is the latest climate litigation directed at governments, oil giant Shell lost a 2021 watershed lawsuit and was ordered to drastically cut its emissions by 2030 due to a "duty of care" to protect future generations. 

It was the first time a private company had been held liable for human rights violations on climate grounds, Paul Benson, a lawyer at environment NGO ClientEarth, told DW at the time.  

"With every positive precedent set, we expand our legal toolkit to bring systemic change," he said. 

But in the US — the world's highest historic greenhouse gas emitter — weak human rights laws mean the Montana case is the first of its kind to be tried, said Merner ahead of the ruling. US courts routinely defer to legislatures on climate and energy policy matters, she added.

With another long-awaited children's climate case, Juliana v. United States, recently given the green light to go to trial, the Montana decision has paved the way for young climate activists to overturn energy policy that explicitly supports fossil fuels.

Climate attribution key to Montana win 

The lead plaintiff in the Montana case, Rikki Held, now 22, was raised on a family ranch in the northwestern state, in a region that also has massive coal reserves mined for high-carbon power generation.

Held testified about wildfires flaring up amid temperatures of up to 43.3 degrees Celsius (110 degrees Fahrenheit) that burned power lines and left her ranch powerless for a month, meaning water couldn't be pumped for the cattle. 

"That's my life," she said with tears in her eyes. "My home is there and it impacts the well-being of myself, my family, my community."

Eleven plaintiffs referenced melting glaciers and wildfire smoke as they spoke about the mental and physical impacts of the climate crisis. 

Steve Running, part of a 2007 Nobel Peace Prize-winning climate science research team, told the court that there was "no doubt" climate change is increasing wildfires and reducing snowfall in Montana. 

His testimony was an example of climate attribution, a science increasingly utilized in climate litigation to gauge the level to which rising greenhouse gas emissions have increased the likelihood or impact of extreme weather events. 

"No hurricane is 100% caused by climate change, but it's impacted by climate change in many different ways," noted Merner, who provides attribution in climate cases. "Attribution science can help us to really tease out the role of climate change in these different events." 

Moreover, climate scientists can quantify attribution with far greater clarity as the weight of scientific consensus has grown. 

Attribution has been key in the landmark climate case against German energy giant RWE brought by Peruvian farmer Saul Luciano Lliuya.

Europe's biggest CO2 emitter is being sued for contributing to the melting of a glacial lake in Peru and thereby threatening Lliuya's village — and his rights. If RWE is forced to pay the costs of flood retention relative to its share of global warming (calculated at .47%), it will open the floodgates for suits against companies for their specific role in climate change, said Merner.  

Backed by a study from Oxford University, RWE's lawyers have struggled to "poke holes" in the case "because the science is very strong," she explained.  

That case is ongoing, but like the action in Montana, such litigation often succeeds when heard in the higher courts, noted Kate Higham, the policy fellow coordinating the Climate Change Laws of the World project at the Grantham Research Institute on Climate Change and the Environment at the London School of Economics and Political Science.    

"When these cases have reached Supreme Courts, particularly when arguments based on human or constitutional rights are involved, then they have generally been quite successful," she told DW.

From human rights to climate disinformation 

While climate cases fought on human rights grounds are rare in the US, strong consumer protection laws are the basis of scores of suits being brought against fossil fuel companies for climate disinformation, according to research by The Center for Climate Integrity in Washington. 

In Oregon, for example, a $52 billion case on behalf of Multnomah County is underway against energy majors including Exxon Mobil, Shell and Chevron. The plaintiffs are suing over the 2021 Pacific Northwest Heat Dome disaster, an extreme heat wave that killed hundreds of people.   

UK-based climate attribution researchers, World Weather Attribution, wrote that the extreme heat experienced in the Pacific northwest that summer was "virtually impossible without human-caused climate change."

The case is founded on the "enormous amount of disinformation" used to maintain the business model of fossil fuel companies, said Jeffrey B. Simon, the attorney leading the case.  

Also known as "climate-washing" litigation, claims against disinformation and greenwashing have risen sharply, according to a report by the Grantham Research Institute. Some 26 climate-washing cases were filed globally in 2022, compared with nine in 2020, stated the report. 

 

Climate cases also being overturned 

In Australia, however, another historic climate case won by young people on human rights grounds in 2021 was overturned a year later by the Federal Court. 

And in Germany in 2022, regional courts dismissed all climate lawsuits against the country's carmakers.

"The law is available to all," said Alice Garton, director of global legal strategy at the Foundation for International Law for the Environment in the Netherlands, during a climate litigation session at the 2023 World Economic Forum. As the number of cases rise, so will the pushback, she added. 

"The values by which society is operating is also changing and citizens are becoming far more aware of the seriousness of this and who is most responsible," said Garton. "That will percolate through to court decisions as well."

Edited by: Tamsin Walker