A plaintiff from the Global South. A carbon giant from the Global North. And a courtroom in a mid-sized German city. On May 28, 2025, the Higher Regional Court of Hamm issued its ruling in what has become Germany’s most high-profile climate lawsuit — Lliuya v. RWE. While the court dismissed the claim brought by Peruvian farmer Saúl Luciano Lliuya against RWE, the country’s largest greenhouse gas (GHG) emitter, it nonetheless delivered groundbreaking findings on civil liability for major GHG polluters. Most significantly, the court held that—at least in principle—companies responsible for large-scale emissions can be held liable under German civil law for the climate-related harms they contribute to.
In this post, we explain the facts and legal architecture of the case and some of the key highlights from the court’s judgment. We also explain why the case matters beyond Germany and what possible impacts it could have on loss and damage litigation in other jurisdictions. In preparing this post, we worked with the original German version of the judgment. For a non-official English translation, see here.
The Facts
In Lliuya v. RWE, Saúl Luciano Lliuya, a Peruvian farmer and mountain guide from Huaraz, filed a civil lawsuit against German utility giant RWE in the Regional Court of Essen, Germany. The suit, which was filed in 2015, alleges that RWE’s historic GHG emissions—amounting to approximately 0.38% of GHG emissions since the Industrial Revolution—have materially contributed to climate change and, specifically, to the accelerated melting of mountain glaciers near Lliuya‘s hometown. (Initially, the plaintiffs estimated RWE’s global share of GHG emissions at 0.47 percent; by the time of the decision, the figure had dropped to 0.38 percent as RWE’s share of global GHG emissions had decreased in the roughly 10 years between the filing of the lawsuit in the first instance and the decision by the Higher Regional Court of Hamm.)
Lliuya further claimed that water from the melting glaciers is increasing the volume of nearby Lake Palcacocha. And this, in turn, is increasing the risk of a catastrophic glacial lake outburst flood (GLOF) that threatens Lliuya‘s property and community. Lliuya sought a proportionate contribution from RWE. Since RWE contributed 0.38% of global emissions, it would be responsible for 0.38% of the costs of appropriate adaptation measures to mitigate the risks to his property—roughly €17,000.
Initially dismissed on causation grounds (among others), the case gained historic momentum when the Court of Appeal – the Higher Regional Court of Hamm – indicated in 2017 that it did not agree with the reasoning of the Regional Court and allowed the claim to proceed to an evidentiary phase. A judicial site visit to Huaraz took place in 2022, and evidentiary hearings were held in 2025.
The Legal Architecture Behind the Claim
Lliuya based his claim on German private law – specifically Section 1004, paragraph 1, sentence 2 of the German Civil Code (BGB), in conjunction with Sections 677 and 812 BGB. Section 1004, paragraph 1 BGB allows a property owner to demand that a “disturber” (“Störer”) – a party interfering with the property – remove the interference or refrain from future interferences. Crucially for Lliuya‘s case, if the property owner removes an actual or imminent interference themselves, they may claim reimbursement for necessary expenses from the disturber — the party who would otherwise be obligated to do so under Section 1004, paragraph 1 BGB.
To succeed in court, the property owner must first present facts in their complaint that the court considers “plausible and substantial” (“schlüssig und erheblich”), i.e., facts that could, if proven true, support the legal claim. Once that hurdle is passed, the case then moves to a second evidentiary phase. In this second phase, the court may include hearing witness testimony and/or submit key disputed questions to a court-appointed expert.
The distinction between these two steps plays an important role in Lliuya v. RWE, because the court affirmed that Lliuya met the first requirement (affirming his claim is “plausible and substantial”). In other words: rising water levels in a glacial lake, partially linked to RWE’s emissions, could—at least in principle—form the basis for a valid legal claim under German private law. As such, if a plaintiff were to succeed in producing the necessary evidence, major GHG emitters could be held liable for property damage, even when the damage occurs abroad, for example, in Global South jurisdictions. In this particular case, the claim ultimately failed only because Lliuya could not prove the specific danger to his property with sufficient certainty.
To recognize the company’s liability, the court had to assess several legal requirements. Some were straightforward—for instance, Lliuya’s co-ownership of the affected property or the attribution of emissions from the subsidiary company to RWE AG. But others became the central battleground of the case. In what follows, we limit ourselves to two key aspects of the case: (1) causation and (2) the issue that the conduct in question—the operation of GHG-emitting power plants—is legal under German law.
Causation
Attribution science plays a pivotal role in advancing climate litigation by bridging the gap between legal responsibility and scientific evidence. As courts require a demonstrable link between GHG emissions and specific climate-related harms, robust attribution science enables plaintiffs to establish causal chains more precisely. Advances in attribution science are reshaping the legal landscape of climate litigation, especially tort-based claims.
There are three major forms of attribution: (1) warming attribution, which links climate change to anthropogenic GHG; (2) source attribution, which links specific actors—particularly major fossil fuel companies—to identifiable shares of historical GHG emissions; and (3) impact and event attribution, which connects climate change to observed damages and extreme weather events with increasing precision. These scientific developments allow plaintiffs to better meet the evidentiary burdens of tort law, particularly on causation, foreseeability, and proportionality of harm.
Attribution science is increasingly capable of translating climate change into individualized legal accountability, opening pathways for liability and compensation through tort doctrines like nuisance, negligence, and failure to adapt. This has been particularly significant in novel cases, where defendants—often large corporations or states—argue that their emissions are only a fraction of the global total. Attribution science helps counter this by quantifying the contribution of specific actors to global warming and its localized impacts, thereby reinforcing legal arguments under tort law, human rights frameworks, and constitutional provisions. For example, in Milieudefensie v. Shell, Dutch courts relied on attribution science and carbon budget analyses to assess Shell’s duty of care.
Under German civil law, for RWE to qualify as a disturber, the interference with Lliuya’s property must be legally attributable to the company. The court first noted that, based on the plaintiff’s submissions, RWE’s actions were causally relevant under the conditio sine qua non test: the company’s emissions were a necessary condition for the harm to occur (p. 46). Other contributing factors do not change this result according to the principles of “complementary causation” (p. 47).
More important, however, is the second requirement for establishing causation under German law – adequate causation (“adäquate Kausalität”). This criterion is meant to exclude chains of causation that are entirely outside the realm of reasonable expectation. In other words, it limits liability to harms that can “fairly” be attributed to the defendant’s conduct.
In the Lliuya case, the court rejected several key arguments made by the defendant as to why the harms suffered cannot be attributed to its conduct. Two, in particular, warrant special attention: (1) the issue of knowledge, and (2) the so-called drop in the ocean argument.
First, the court held that RWE could have been aware of the harmful effects of GHG emissions since at least the mid-1960s. Referring to the state of scientific understanding in the 1950s and 1960s, the court found that it was already possible at that time to recognize
“that the [GHG] emissions produced as a ‘waste product’ during coal-fired power generation were and are capable—not merely through a chain of particularly extraordinary circumstances, but due to ordinary physical processes—of contributing to the melting of glaciers as a result of the atmospheric greenhouse effect.” (p. 50)
A company of the defendant’s scale, the court held, has an ongoing duty to stay informed about advances in science and technology—by tracking developments presented at scientific conferences, attending industry events, and reviewing the full breadth of international scholarly literature (p. 50). For an energy-producing company, the causal links between fossil fuel combustion and environmental harm would have been recognizable had the company continuously kept up with scientific and technological advances in the field of fossil-based energy production.
The court also rejected the argument that the defendant’s contribution was too minor to matter. RWE had argued that its share—0.38 percent of global industrial GHG emissions—was too small to establish adequate causation.
The court disagreed. It held that the significance of a contribution cannot be judged by its absolute percentage alone but must be evaluated in relation to the contributions of others. In the words of the court:
“In cases of multi-causal liability, a comparative assessment must always be made. The relevant standard is not the mere percentage of contribution—such as 5% or 10%—but rather the size of that contribution in relation to other contributing causes.” (p. 51)
Or, to use the popular image of the “drop in the ocean,” the drop should not be assessed in relation to the entire ocean, but in relation to other drops. When compared to other emitters, the court found that RWE’s emissions were in fact substantial. Indeed, according to one study, RWE ranks 42nd among the world’s largest carbon major entities.
But isn’t emitting GHGs legal?
The court also rejected RWE’s argument that a claim can only be brought under Section 1004(1) BGB where the defendant’s conduct is unlawful. The conduct at issue in this case – emitting GHG – is not unlawful. Accordingly, it was argued that the plaintiff has a duty to tolerate such lawful conduct (Duldungspflicht). Among other reasons, RWE claimed it would be contradictory for a state-issued public permit to authorize the operation of a GHG-emitting facility, while at the same time allowing for private liability under civil law.
The court held that the legality of the conduct itself is not decisive; what matters is the harm that results from it (p. 65). Section 1004 BGB, the court emphasized, is designed to provide comprehensive protection of property. That protection would be undermined if harm caused by lawful actions were categorically excluded from liability.
Nor, according to the court, does the fact that RWE holds permits and approvals from German authorities create a duty for the plaintiff to tolerate a specific and imminent threat to his property (p. 79). Administrative permits do not, as a rule, establish a duty of tolerance for third parties. In relation to public law, the court emphasized, there exists an “autonomy of private law duties of care” (p. 80).
So why did Lliuya lose the case?
To sum up the court’s reasoning so far: If a plaintiff can prove that the requirements of Section 1004(1) of the German Civil Code are met, major GHG emitters can, in principle, be held liable for climate-related damage. One of those requirements, however, is proof of concrete harm – or at least a sufficiently imminent threat of harm – to the plaintiff’s property.
According to the court, Lliuya failed to establish that. Lliuya needed to show that a GLOF was likely to occur within the next 30 years (a time period that the court, in this specific case, considered as the maximum period within which a temporal connection required under German law between the lawsuit and the possible damaging event still exists) and that it posed a serious threat to his home. Based on expert opinions commissioned by the court—conducted on site in the Andes—the judges concluded that the risk of a GLOF threatening the plaintiff’s property within the next 30 years was just one percent. The court opined:
“Such a small percentage rules out any serious concern of an imminent violation of rights. The property damage feared by the plaintiff does not, in factual terms, appear tangible; on the contrary, it must be considered highly unlikely.” (p. 112)
This finding has drawn criticism as overly restrictive. In its risk analysis, the court diverged from the conclusions of the plaintiff’s privately appointed experts and instead followed the findings of the court-appointed experts (as is regular practice in German civil procedure). It rejected, for example, the claim that the plaintiff’s property faced a sufficiently probable threat from rockfalls. The court also declined to apply the plaintiff’s proposed “climate factor”—a multiplier between 2 and 4 intended to reflect the accelerating effects of climate change on mountain stability. In other words: if the probability of damage occurring can be quantified (in this case: one percent), then the possibility that mountain stability could continue to deteriorate in the future due to the climate crisis must be taken into account (so, in this case, not one percent, but a damage probability between two and four percent).
The court concluded that the court-appointed experts had already incorporated climate change adequately into their analysis. Even if the climate factor were applied, the court reasoned, the probability of harm would still fall below five percent—too low, in its view, to sustain a claim under Section 1004(1) of the German Civil Code (p. 127).
Conclusion
Even before the decision, Lliuya v. RWE was a unique case, with evidentiary hearings and a cross-border site inspection, showing procedural innovation and progress unmatched by other climate damages claims. Lliuya v. RWE is widely recognized as a pioneering climate lawsuit that tests the potential of domestic courts to enforce transboundary accountability for climate harm. As the first case in which a private company is being sued by an individual for its proportional contribution to climate-related damage abroad, it pushes the boundaries of traditional tort law and creates a novel legal pathway for climate justice. The case’s narrow, proportional remedy reflects a measured, evidence-driven approach that has inspired similar suits worldwide. It thus serves as a real-time test case for courts around the world, demonstrating how domestic legal systems might bridge the gap left by the absence of enforceable international mechanisms for climate loss and damage.
Despite the dismissal, the case has redefined what is possible in climate litigation and catalyzed a new generation of pro-rata corporate accountability suits. With the recognition that the claim is possible, other similar test cases will likely be brought in other jurisdictions. A similar case is pending in Switzerland. In Asmania et al. vs Holcim, four inhabitants of the Indonesian island of Pari have sued Swiss-based cement company Holcim for its 0.42% emissions share and resulting sea-level rise risks (see here), requesting mitigation, adaptation, and loss and damage claims. Both cases rely on the same core principle: that large corporate emitters can be held responsible for their fractional, yet significant, contributions to global climate harm. The decision in Lliuya might spark further transnational loss and damage claims, a subset of climate litigation that remains underexplored.