Hiking back home with a flock of sheep on his Andean hillside farm, Saul Luciano Lliuya pauses at a steep, rocky turn and glances at the snow-capped mountains that have dominated the landscape for millions of years.

"The snow caps, the glaciers are disappearing," said Lliuya, a 43-year-old farmer and trekking guide born and raised in Peru's Cordillera Blanca mountains. 

 "Everyone that lives here is worried about that. Like all human beings, we think of our wellbeing, of our survival, and what we will eat and drink in the next years."

In a fight to secure his home from climate disaster, Lliuya is at the heart of an "unprecedented" legal claim that could herald a new age of climate justice and force the world's major greenhouse gas emitters to pay for their role in heating the planet.

The Quechua-speaking Peruvian, who lives near to Huaraz — a city of 150,000 people 3,000 meters above sea level — is suing German energy multinational RWE for its alleged role in increasing the likelihood of climate disaster in the region by burning fossil fuels. 

Lliuya wants RWE to cover some of the costs for protective measures against potentially deadly future flooding in the town — a risk he says is growing as the planet heats. 

The company, founded in 1898, made €3.2 billion ($3.4 billion) in profit last year and has been named Europe's biggest polluter.

"For me, it's difficult. It's a battle against giants," said Lliuya, who lives a frugal life the hills with his wife and two children harvesting corn and potatoes.

A potentially breakthrough legal action 

The much-anticipated legal proceedings are the culmination of nearly a decade of efforts. Lliuya filed his lawsuit with the support of NGO Germanwatch, at the District Court Essen in Germany, where RWE is headquartered, in November 2015. Initially, the court dismissed the claim, but he successfully appealed at a higher court in 2017.

 "The court agreed for legal evidence to be given in this case, which has never happened before," said Christoph Bals, policy director of the Bonn-based organization. "If we win the final ruling, it means all the biggest emitters in Europe can be brought to court."

In May 2022, a group of independent experts and judges traveled from Germany to Peru to assess to what extent the plaintiff is threatened by imminent climate disaster. This August, the report was shared with the parties, and the hearing is set to begin within months in what is the first transnational climate litigation case of its kind to reach this stage.

 "The case could be a real breakthrough moment," says Birsha Ohdedar, a lecturer in climate change and environmental law at London's School of Oriental and African Studies. "That a litigant in the Global South bringing this against a company in the Global North is hugely significant for the climate justice movement."

The looming threat from above 

The Huaraz threat comes from a glacial lake, located above the city, says Lliuya.

An avalanche of ice or rock falling into the lake could cause a flood wave with deadly consequences. Locals are well aware of the danger. In 1941, an earthquake caused a chunk of glacier to fall into the lake, triggering a surge of water that killed 1,800 people in the city. 

"When you read the news reports and when they declare an emergency at Lake Palcacocha, you feel very tense and worried," said Lliuya. In 2014, he lost a friend and fellow mountain guide, who died during a trek in the rapidly changing terrain. 

As the planet heats up and glaciers melt, the swollen lake is potentially more deadly. The volume of water in Palcacocha is 34 times greater than in 1970, found a study by the University of Oxford. More broadly, Peru has lost over half its glaciers in the last 50 years. 

According to Lliuya's claim, Palcacocha must be drained to install flood prevention measures, such dams and a glacial flood outburst early warning system. The farmer is asking for RWE to provide €17,000 or 0.47% of the projected $4 million total cost. RWE is responsible for 0.47% or 6.8 billion tons of global CO2 emissions since the start of the industrial era in 1751 up until 2010, according to a 2014 report.

If the German court rules that Huaraz does face a flood risk, it will then determine how much human-made climate change and RWE's emissions fuel that risk. Lliuya's team is confident this could be proven, given the advances in climate attribution science, including in the latest report by UN climate body, the IPCC. 

But why is RWE being sued? 

Lliuya's case is a leading example of a recent wave of climate litigation. The number of climate change-related court cases has more than doubled since 2017, reaching a total of 2,180 in 2022, according to research by Columbia University's Sabin Center for Climate Change Law.

It's based on a "global neighborhood" argument — that emissions from one side of the globe affect everyone else around the world. RWE operates in 27 countries across the world, including neighboring Chile and Brazil, but not in Peru.

Germanwatch estimates that over 50 jurisdictions across the globe share the basic provision being used to fight the case.

"We think that about half of the 100 biggest emitters in the world are at high risk of similar cases in their jurisdictions," said Bals. "This would be a good driver for these companies to step out of fossil fuels as soon as possible."

Guido Steffen, a spokesman for RWE, said in a written statement to DW that there was "no legal basis" to Lliuya's claim. 

"Individual emitters are not liable for universally rooted and globally effective processes like climate change," he wrote, adding that the company supports Germany's 2030 coal phase-out and plans to be carbon neutral by 2040.

According to the nonprofit Client Earth, RWE emitted 106 million tons of CO2 from its coal operations in 2017. In 2020, almost 80% of the electricity RWE generated came from non-renewable sources.

Fears for the future 

Back in the Cordillera Blanca, climate change continues to impact Lliuya and his homeland in different ways. 

More extreme, unpredictable weather has shifted the rainy season, meaning that only one rather than two harvests are now possible. Pests are thriving in warmer conditions. He fears that eventually farmers like him will run out of water for drinking and irrigation. Tourism, too, could dry up.

"Like all country people, we can see the glaciers are disappearing," said Lliuya, sitting outside his stone house as the sun sets over the Andean highlands. "That's why I took the opportunity to make a legal claim. If we win, I think that the glaciers will win."

Edited by: Jennifer Collins