Introduction 

On 28 May 2025, the Hamm Higher Regional Court handed down the final verdict in one of the world’s most closely watched climate change cases: Luciano Lliuya v. RWE AG. It is also one of the longest-lasting cases. First filed in 2015, plaintiff Saúl Luciano Lliuya alleged that because their historic greenhouse gas emissions have contributed to climate change, German energy giant RWE is legally responsible for paying a portion (proportional to their emissions) of the cost of protective measures to prevent the destruction of his property in Peru from a lake outburst produced by climate change-induced glacial melting. 

Lliuya’s claim was rejected; the court found that there was not enough evidence that the potential glacial outburst posed a sufficiently acute threat to his property. On the law, however, the court’s judgment was favourable to the plaintiff’s argument. It widely extended the scope of potential future lawsuits against major greenhouse gas emitters. The decision means that German corporations can, in principle, be held responsible for climate change-related harms – and threats of harm – wherever they occur in the world. 

Background 

Saúl Luciano Lliuya is a resident of Huaraz, in the Peruvian Andes, where he works as a mountain guide. His house, along with the rest of Huaraz, is at serious risk of flooding from a glacial lake outburst of nearby Lake Palcacocha. This risk has been growing in recent years due to climate change-induced glacial melting. The cost of municipal flood defences to protect Huaraz – and Lliuya’s home – was found to be 3.5 million Euros. 

In 2015, Lliuya – with the assistance of Peruvian NGO Wayintsik Perú and German NGOs: Germanwatch and Stiftung Zukunftsfähigkeit – brought suit against RWE in Germany, in order to recoup a portion of the cost of providing flood defences for Huaraz. RWE is Europe’s largest carbon dioxide emitter, and was, at the time, responsible for 0.47% of the world’s total greenhouse gas emissions since 1965. Lliuya thus requested that the company pay a corresponding 0.47% of the 3.5 million Euro cost of protective measures for Huaraz, a total of roughly 17,000 Euros.[2]  

Lliuya’s claim was based on fundamental property law principles contained in § 1004 of Germany’s civil code, which allows property owners to make a claim for the elimination of any impending impairment to their property for which the defendant is responsible.[3] In 2016, Lliuya’s claim was dismissed by the Essen District Court, in part because the court found it too difficult to show linear causation, given the complex relationship between RWE’s specific emissions and the particular harm that Lliuya would suffer, and because a decision would not be able to provide Lliuya with any redress, even if RWE were to cease its emissions. The case was appealed to the Higher Regional Court of Hamm, which in 2017 ruled that the case was admissible. The evidentiary stage involved two important components: First, determining the extent to which Lliuya’s home was threatened by flooding or mudslides due to increased glacial melt – caused by the effects of climate change. Second, determining the extent to which RWE’s contribution to global emissions of carbon dioxide contributed to the increased risk of flooding or mudslides. 

Higher Regional Court of Hamm’s (Oberlandesgericht, OLG) Decision 

The Higher Regional Court of Hamm handed down its judgment on 28 May 2025, dismissing Lliuya’s claim, without granting a right to appeal, therefore bringing an end to one of the longest-running climate litigations.[4] Despite strong disputes by the plaintiff on the methodology used to analyse the risk, the court found that the probability that glacial lake flooding would affect the plaintiff’s house within 30 years was limited to around one percent, and that the consequences for the plaintiff’s house would be insignificant even if there were to be flooding.[5]  

Nevertheless, in terms of the law or legal principle, the decision is remarkable and has the potential to fundamentally affect litigation on major emitters’ responsibility for the effects of climate change. 

Most importantly, the court accepted that in principle RWE could be held liable under § 1004 of the German Civil Code.[6] The court stated that if there is a threat of damage due to a company’s past carbon dioxide emissions, then that polluter may be obliged to take measures to prevent such harm from taking place. If they refuse to do so, then they can be held liable even before actual damages are incurred. If a company’s past carbon dioxide emissions have already caused harm, then it would be liable for those damages.[7] Therefore establishing both a preventative and reparative obligation on companies. The court also emphasised that the great distance between the site of RWE’s emissions in Europe and the plaintiff’s home in Peru was irrelevant to the question of liability.[8] 

The court dismissed arguments that harms related to climate change would have been unforeseeable to the defendant, stating that the potential damages of carbon dioxide-induced climate change were evident to the optimal observer – such as an energy producing company – by the mid-1960s, thanks to the publication and subsequent discussion of Charles Keeling’s 1958 study of atmospheric carbon dioxide concentration shifts and associated warming.[9] The court emphasised that a major industrial corporation should, in any case, monitor the progress of scientific and technological developments, including by following the results of scientific congresses and specialist events.[10] 

The court dismissed RWE’s “everyone against everyone” argument that accepting liability would overstretch the courts and that all citizens could be prosecuted for their role in creating climate change risks, due to the political nature of this argument.[11] It also dismissed the defendant’s claim that climate change was solely a political question for the lawmaker, noting that climate-related damages can also lead to judicial involvement, just as with any other case of property impairment.[12] 

Thus, while the court’s decision was a victory for RWE in the narrow sense and they will not have to pay for their part in the increased risk posed to Luciano Lliuya, the decision has been hailed by climate change activists as an important and extremely beneficial precedent for climate change litigation. 

Significance 

After ten years of litigation, the case of Luciano Lliuya v. RWE AG has already proven influential. In the past few years, there have been similar cases filed in Switzerland,[13] Italy,[14] Belgium,[15] and elsewhere. Provisions similar to § 1004 of the German Civil Code exist in many other countries, providing more opportunities for strategic litigation. 

Although Lliuya has now lost his appeal, the court’s findings are groundbreaking in terms of legal principle. It is now clear that, at least under German law, major emitters of greenhouse gases can be held liable for their contributions to harms caused by the effects of climate change. This decision will undoubtedly lead to further litigation on this question, both in Germany and beyond. The question remains as to how the Courts will apply this principle in practice, given the difficulties with establishing an increased risk to the plaintiff’s property and potential methods to limit that risk. 

[1] With thanks to Andrew Wolman for preparing this post. 

[2] Luciano Lliuya v. RWE, Statement of Claim (23/11/2015) at 19-20. Unauthorised translation at https://climatecasechart.com/wp-content/uploads/non-us-case-documents/2015/20151123_5-U-1517-OLG-Hamm-Case-No.-2-O-28515-Essen-Regional-Court_complaint.pdf.  

[3] Ibid, at 25. 

[4] Luciano Lliuya v. RWE, Case number 5 U 15/17 OLG Hamm, at 2. This and following cites are to an English-language translation of the judgment posted on the website of one of the NGOs supporting the plaintiff, at https://rwe.climatecase.org/sites/default/files/2025-05/Judgement%20of%2028%20May%202025%20en-anon.pdf. 

[5] Ibid, at 110. 

[6] Ibid, at 4-5. 

[7] Ibid, at 37-9. 

[8] Ibid, at 39. 

[9] Ibid, at 49-50. 

[10] Ibid, at 50. 

[11] Ibid, at 63. 

[12] Ibid, at 64. 

[13] Asmania et al. vs Holcim, https://climatecasechart.com/non-us-case/four-islanders-of-pari-v-holcim/.  

[14] Greenpeace Italy et. Al. v. ENI S.p.A., the Italian Ministry of Economy and Finance and Cassa Depositi e Prestiti S.p.A., https://climatecasechart.com/non-us-case/greenpeace-italy-et-al-v-eni-spa-the-italian-ministry-of-economy-and-finance-and-cassa-depositi-e-prestiti-spa/. 

[15] Hugues Falys, FIAN, Greenpeace, Ligue des droits humains v. TotalEnergies (The Farmer Case), https://climatecasechart.com/non-us-case/hugues-falys-fian-greenpeace-ligue-des-droits-humains-v-totalenergies-the-farmer-case/.