After nearly a decade of legal proceedings, the Higher Regional Court of Hamm has delivered its long-anticipated judgment in the case of Saúl Luciano Lliuya v. RWE. While the court ultimately dismissed Lliuya’s specific claim, the ruling marks an important moment for climate litigation. This is the first time a European high court has ruled that major contributors to global warming can, in principle, face liability under civil law for their contributions to the climate crisis. Though Lliuya didn’t win financial relief in this case, the court’s reasoning delivers a powerful affirmation that large emitters like RWE could face legal consequences for their role in climate harm.
What the Court Decided
Saúl Luciano Lliuya, a Peruvian farmer and mountain guide from the city of Huaraz, brought a civil lawsuit against RWE, one of Germany’s largest energy companies and a historic emitter of planet-warming CO₂. He argued that RWE’s emissions contributed to the melting of glaciers above his city, increasing the risk of catastrophic flooding from the nearby glacial lake Laguna Palcacocha. Lliuya asked the court to require RWE to pay a proportional share of the flood protection costs based on the emissions traced to its activities and products.
The court ultimately dismissed the claim—not because the science was in dispute, but because Lliuya could not meet the stringent legal standard under German nuisance law, which requires a narrow risk analysis threshold of a specific, imminent threat. This technical finding does not overshadow the broader implications of the decision. On the contrary, the court affirmed key legal and scientific principles that strengthen the foundation for future climate cases.
What Makes This Ruling Meaningful
While I’m not a lawyer, I have been working at the nexus of science and law for a number of years now and from my perspective the ruling in Lliuya v. RWE is important for three big reasons:
1. It affirms that courts can, and should, hear climate cases. The court confirmed that climate harms can be addressed through ordinary civil law, not just through political processes. This means that when a company’s emissions contribute to climate-related harms, even those occurring far from where the emissions originated, civil courts can weigh in. It’s a powerful statement that legal systems can respond to the global nature of the climate crisis.
2. It acknowledges that climate contribution can be proportional. This is wonky, but stick with me. The judges accepted that RWE’s contribution to global CO₂ emissions (roughly 0.4% over several decades) was legally meaningful. That may sound small, but in a world of cumulative emissions, it’s substantial. By recognizing that even a fraction of responsibility matters, the ruling opens the door for holding major polluters accountable in ways that reflect their share of the problem.
3. It highlights that companies should have known better. The court made clear that companies like RWE had enough scientific information going back to the 1960s to understand that their emissions could cause serious harm. This wasn’t a surprise. The risks were known, and the companies kept up with business as usual anyway. That matters because, under the law, being able to foresee harm often means you’re responsible for helping to prevent it. This aligns with what we documented in our Decades of Deceit report outlining that fossil fuel companies knew the dangers, yet chose disinformation and delay over action.
In other words, climate harm is foreseeable, contribution is measurable, and courts can play a critical role in hearing these claims.
Science in the Courtroom
This ruling didn’t shy away from the science: it engaged with it directly and respectfully. The court:
- Accepted that human-caused emissions are the driving force behind climate change and that this warming has led to increased glacier melt in the Peruvian Andes. The court acknowledged that the current level of glacial retreat would not have occurred without human activity.
- Considered company-level emissions data, specifically the Heede study, which links historic emissions to individual fossil fuel producers, is a legitimate basis for evaluating a company’s share of responsibility. This data is now publicly available and regularly updated online through InfluenceMap.
- Acknowledged the use of regional attribution science. The court recognized peer-reviewed research showing that the vast majority of warming in Huaraz, the region where the plaintiff lives, is due to human-caused climate change.
- Understood that climate change results from the buildup of emissions from many sources over time. In doing so, the court applied a legal framework that allows for shared responsibility among emitters, rather than requiring a single, isolated cause.
Perhaps most notably, the court rejected the idea that emissions must be tied to a specific harm in a linear way to establish liability. Instead, it accepted that science can quantify a company’s contribution to climate harms, even if those risks stem from complex, cumulative processes. That distinction is critical. It shows the court recognized scientific attribution as a valid and rigorous method for assessing climate responsibility under civil law.
Accountability Beyond Borders
The court made it clear that having a government permit doesn’t let companies off the hook. Even if RWE was allowed to operate its power plants, that doesn’t mean it’s free from responsibility when those operations contribute to real-world harm. Legal approval to operate a business isn’t a free pass to pollute with impunity.
The ruling also confirmed that people harmed by climate change don’t have to live in the same country where the emissions occurred to seek justice. In this case, the court accepted that German law could apply even though the plaintiff lives in Peru. That’s a big deal. It means communities around the world may have a legal path to hold major polluters accountable, no matter how far away the emissions took place.
This kind of decision can open the door for more cases that seek real accountability from fossil fuel companies.
What Comes Next
The ruling in Lliuya v. RWE shows that courts are increasingly willing to listen to climate scientists, accept probabilistic modeling, and treat emissions data as credible evidence of harm. The case also demonstrates how far we’ve come in climate litigation and where things may go next.
There is a growing wave of litigation that aims to hold fossil fuel companies accountable for their emissions and/or for the deception and delay that have deepened the climate crisis. The RWE ruling strengthens those efforts by putting legal weight behind what science has already shown.
Saúl Luciano Lliuya has changed the legal landscape. His courage in bringing this lawsuit, backed by rigorous science and an international coalition, helped establish that major polluters may be held accountable for their contributions to climate change. Thanks to his efforts, plaintiffs will be able to build on this precedent and seek accountability for climate harms through the courts.