Lawsuits concerning the impacts of climate change make causal claims about the effect of defendants' greenhouse gas (GHG) emissions on plaintiffs and have proliferated around the world. Plaintiffs have sought, inter alia, compensation for climate-related losses and to compel governments to reduce their GHG emissions.To date, most of these claims have been unsuccessful. Here, we assess the scientific and legal bases for establishing causation and evaluate judicial treatment of scientific evidence in 73 lawsuits. We find that the evidence submitted and referenced in these cases lags considerably behind the state-of-the-art in climate science, impeding causation claims. We conclude that greater appreciation and exploitation of existing methodologies in attribution science could address obstacles to causation and improve the prospects of litigation as a route to compensation for losses, regulatory action, and emission reductions by defendants seeking to limit legal liability. Main textPlaintiffs have brought over 1,500 climate-related lawsuits worldwide, and the number of claims filed continues to increase 1 . Without effective non-judicial mechanisms providing compensation for climate-related loss and damage, plaintiffs have filed lawsuits seeking financial remedies from high-emitting corporations for losses suffered due to climate change 2 . Robust scientific evidence is critical to the success of such claims 3-5 . For example, claims for compensatory damages must demonstrate a causal link between the defendant's behaviour and the plaintiff's injury. Recognising this, recent literature has drawn on analogous categories of case, such as toxic torts, in which modified causation tests reconcile legal causal analysis with scientific evidence that demonstrates multiple entities' contribution to the risk of harm 5 . However, despite developments in scientific 6 and legal theory 5 on causation and attribution of climate change damages, compensatory-damages claims have been unsuccessful. Other lawsuits challenge inadequate state and corporate climate change mitigation targets and policies 7 . To establish admissibility, these claims may also rely on courts finding that emissions resulting from defendants' policies led to impacts affecting the plaintiffs.A claim must first meet procedural requirements that render it admissible, including 'standing', which establishes that plaintiffs have legally protected interests that entitle them to bring the claim. Demonstrating a connection between defendants' actions and plaintiffs' injuries may contribute to meeting the standing requirement. To date, admissibility has been the primary outcome-determinative obstacle for climate

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With prominent court cases like Lliuya v RWE in Germany and, in particular, the decisions of the German Constitutional Court in Neubauer et al. v Germany, and the Hague District Court (the Netherlands) in Milieudefensie et al. v Royal Dutch Shell repeatedly making headlines in 2021, climate litigation has successfully gained a role as an important component of achieving ambitious climate goals. Some cases seeking more ambitious emission reductions have been successful whereas, to date, those seeking compensation or restitution for losses or damages have not. Many recent publications argue however, that developments in climate science could lead to favourable outcomes for plaintiffs in some of these loss and damage types of lawsuits, depending on domestic legal framework and

Some climate lawsuits qualify as landmark cases, because they either mark an unexpected turning point in environmental jurisprudence, or they introduce a new conceptual analysis of the law vis-à-vis the global challenge of climate change. The decision of the German Federal Constitutional Court from March 2021 meets both criteria, it has already defined climate policy and law-making in Germany, and it revolutionised the traditional concept of ‘interference’ with fundamental rights under the German Basic Law. This article examines the order and its significance for climate litigation, legislation and constitutional doctrine, and it analyses how international law defines the state’s objective to protect the climate pursuant to Article 20a Basic Law, including for future generations. On that basis, the article argues that the Court's approach towards intergenerational equity remains limited due to the perception of the carbon budget as ‘freedom budget’.

Does international law afford individual rights to enforce climate action of States and if so, is there a legally binding standard of climate protection that domestic courts can apply? The Gerechtshof Den Haag (Hague Court of Appeal) in the Urgenda decision of October 2018 has answered these questions in the positive. The Hague Court of Appeal thereby acknowledged the existence of a 'duty of care' in Dutch law based on the European Convention on Human Rights. A closer analysis of the judgment reveals that the concrete content of this duty of care is not derived from human rights, but from scientifically proven and internationally endorsed greenhouse gas emission reduction targets which are imperative to achieve the temperature goal of the Paris Agreement. This article analyses the judgment and examines whether it is consistent with the existing case law of the European Court of Human Rights. It demonstrates that the judgment forms part of a tidal wave of judicial enquiry into the accountability of governments for their climate action on the basis of human rights and that it is the virtue of human rights law to be conducive to resolving the accountability issue of governments for their climate action. More evidence is needed to substantiate that a new 'European Consensus' emerges that comprises not only agreement on an ambitious global temperature goal but translates this into individual rights to enforce climate protection.