In the pending Lliuya case Peruvian citizen filed a case against the German energy company RWE. The claimant demands a contribution to the costs of suitable protective measures against the danger of flooding and hence damage to his house in Huaraz, Peru, likely to resulting from a spill-over caused by a nearby glacier lake that is melting due to climate change. The case is mainly based on § 1004 (in combination with § 823 para. 1 German Civil Code) which includes the principle of nuisance law that, if the ownership is unlawfully interfered with, the owner may require the disturber to remove the interference. The claimant argues that RWE contributed to global warming by emitting 0,47 % of world-wide emissions and hence created a situation which, in a linear fashion, adds to the risk of flooding through a melting glacier.  Some of the intricate problems of the case are how to deal with damage that occurs at a long distance, in the long term, and in a cumulative fashion and related questions of causation.

Moreover, the NGO Deutsche Umwelthilfe brought actions against BMW and Mercedes-Benz arguing that they produce vehicles which are particularly damaging for the climate and therefore infringe a fundamental right to climate protection. The claims are based on the right to injunctive relief under § 1004  para. 1 and § 823 para. 1  German Civil Code. The NGO argues that the defendants are inter alia obliged to prevent infringements of fundamental rights by refraining from the distribution of climate-damaging vehicles with a combustion engine after 2030.

Future claims under contract law, tort law, hazard- and strict liability law as well as various claims stemming fromproperty law, in particular nuisance law are generally conceivable. Claims can be filed against activities that have effects elsewhere in the world, as they can be based on either the place of action or of the result of an action. Potential cases may, for instance, concern situations where property owners have to adapt to an increased risk of flooding or suffer from damage after extreme weather events. Strict liability and nuisance law may be the most suitable bases for successful claims in this regard, as they do not require a fault. Claims against damage or nuisance to property caused by private actors need to show cumulative, long-term and distant damage and issues of causality may arise.

There are several cases of project-specific litigation in environmental matters that are relevant for climate litigation. Most of these cases are based on planning and licencing laws as well as their respective procedural dimensions. However, to date, no case explicitly challenging the government for authorising a project that frustrates efforts to mitigate of climate change or leads to ineffective adaptation has been decided by courts.

There is a long line of cases, e.g. relating to nuclear power (BVerfG, 1979), noise by air and car traffic (BVerfG, 1981, BVerfG, 1988), ozone (BVerfG, 1995), electro smog (BVerfG, 1997). Claimants commonly allege that the State had breached its duty to actively protect the fundamental rights of its citizens. However, in none of the mentioned cases the Constitutional Court actually assumed that a protective duty had been violated. More specifically, in a case regarding a planning permission for a long-term deposition of nuclear waste (BVerfG, 2009), based, among others, on Articles 20a, 2 II, 14 and 1 of the German Constitution (Basic Law – BL), the Constitutional Court held that citizens have to accept a minimum residual risk. However, other cases also provided that risk prevention can be part of the protective duty of the State if it serves to prevent fundamental rights violations.

In the pending law suit DUH vs. Stralsund Mining Authority (2020) the NGO Deutsche Umwelthilfe argued that the Mining Authority must review its 2018 planning permission issued on the basis of Article 43.1.2 Energy Industry Law (former version) for a gas pipeline and to order risk assessment measures linked to the related methane emissions, based on recent scientific findings.

In order to have standing, individuals have to show that they can rely on a norm that provides a direct entitlement for them or is intended to protect them as a directly concerned third party, e.g. as a neighbour. This requirement is challenging for climate change litigation because the rules requiring the authorities to take climate protection into account normally do not single out individual rights or protections of third persons. Therefore, planning law decisions that are detrimental to the climate may only be challenged where other interests are at stake that include an individual rights dimension.

Due to the implementation of the Aarhus Convention, claims based on procedural violations play a particular role for processes of planning and licensing. The Environmental Remedies Act provides that environmental NGOs can inter alia challenge acts that require an environmental impact assessment on substantive or procedural grounds. This is an exception to the mentioned century-old German administrative law doctrine of the subjective public right since by their very nature, NGOs will normally not be directly concerned in their rights. This new instrument of claims by NGOs by way of collective action is still in process to becoming accepted in practice. Furthermore, the implementation of the Aarhus Convention – and several rulings of the European Court of Justice – has widened the scope for standing of individuals, particularly in regard to rights of information and participation.

With regard to legal grounds in the area of planning law, relevant norms can be found in the Federal Construction Code or in the Federal Code on Protection against Emissions, often complemented by law of the respective federal state. Regional plans that concretise spatial planning can play a major role, as well. Yet, taking into account global climate protection in the balancing exercise during planning processes has so far not always worked very well, as this concern is not taken sufficiently seriously and has been considered as too abstract.

In the area of licencing law, climate litigation could become relevant where a building or piece of infrastructure is subject to a particular risk from climate change, e.g. flooding, which may cause damage to the neighbour´s property. So far, however, no case has been decided along those lines.

Regarding the procedural dimension, § 1 Environmental Information Act provides a right to information. Individuals can also challenge licensing decisions that are not based on a (sufficient) environmental impact assessment to the extent that the lack of such an assessment has made it impossible for the claimant to participate in the deliberation process (§ 4 I, III in conjunction with § 1 Environmental Remedies Act).

Finally, claimants can hold the State accountable for legal violations through the instrument of State liability (Article 34 BL in conjunction with § 839 of the German Civil Code). In the Forest-Damage-cases (BVerfG, 1998) private forest owners sued the State, alleging a violation of their property right (Article 14 I BL) due to increased air pollution, which would cause their forests to decline and be attributable to the State. However, the Constitutional Court held that liability for a global phenomenon such as forest decline as a result of distant emissions is a matter for the legislator and cannot be established by courts. State liability may be triggered indirectly in future cases, if the right to life, physical integrity or property is at stake.

In the area of planning and licencing law, breaches can mainly be remedied in so far as planning decisions are overturned or licences withheld. Furthermore, § 6 of the Environmental Information Act grants an individual remedy where information regarding infrastructure projects is unduly withheld.

In Germany, there have been several cases where citizens or NGOs filed lawsuits against the State alleging that its inadequate climate change mitigation policy violates national law.

In Family Farmers and Greenpeace Germany v. Germany (VG, Berlin, 2019)before the administrative court of Berlin claimants alleged that by abandoning its 2020 mitigation target the government had acted unlawfully in view of the general principles of self-binding administration as well as fundamental rights. However, the court dismissed the case due to a lack of standing. It held that, while the government’s climate policy is generally justiciable, the specific target was non-binding and internal, and a violation of fundamental rights was not substantiated.

The 2021 landmark decision by the Federal Constitutional Court (BVerfG, 2021), concerned the argument that the Federal Climate Protection Act’s target of reducing greenhouse gas emissions by 55% by 2030 from 1990 levels violated fundamental rights of the claimants and did not sufficiently take into account Germany’s obligations under the Paris Agreement. The claimants inter alia challenged the compatibility of the Climate Protection Act with Article 20a of the German Constitution (Basic Law – BL), stipulating the aim to protect the environment for future generations. The Constitutional Court found the claims to be partly justified and held that Article 20a BL obliges the legislator to protect the climate and pursue efforts towards climate neutrality, particularly with a view of future generations. The legislator had failed to distribute the burden of the remaining carbon budget on the path towards climate neutrality proportionally along the remaining years, so that harsher future intrusions into fundamental rights may constitute an undue burden. Therefore, the Court ordered the legislator to set clear provisions for reduction targets for the whole period until climate neutrality will be reached.

Following this decision, the NGO Deutsche Umwelthilfe filed lawsuits against the German Federal Government, requesting the adoption of a specific and adequate climate protection programme that meets the cross-sectoral greenhouse gas emissions and the targets for the transport sector laid down in the Climate Protection Act. Moreover, with support of the same NGO, eight lawsuits were filed with regards to lacking regional Climate Protection Acts in the respective federal States in Germany. Claimants seek an order for the establishment of such acts, and/or for their targets to be aligned with the goals of the Paris Agreement.

In general, individuals may allege a violation of their own fundamental right before the Constitutional Court under Article 93 I Nr. 4 a BL. Similarly, in administrative proceedings, individuals need to substantiate an infringement of a subjective right. The prerequisite of individual concern can be challenging for claimants in climate change cases, where a concrete violation may be hard to pinpoint and often only materialises in the future. Only certain State organs may challenge the legality of climate laws or policies based on violations of non-subjective legal norms (Article 93 I Nr. 2 BL, e.g. BVerfG, 2007).

According to § 3 Environmental Remedies Act (Umwelt-Rechtsbehelfsgesetz) only recognized associations have standing, but only where cases covered by § 1 Environmental Remedies Act are concerned. Alternatively, associations may argue that they have a right of action based on procuration provided that an individual would have standing. A right of action by Greenpeace based on the CJEU’s jurisprudence (CJEU, 2017) had been rejected in Family Farmers and Greenpeace Germany v. Germany, because the challenged German Climate Protection Goal 2020 had not been based on European provisions (e.g. VG Berlin, 2019).

With regards to the legal basis, the German Basic Law does not include an explicit or implicit right to environmental protection that goes further than what can be inferred from the respective substance of the various fundamental rights. Claims may in particular be based on Article 2 II 1 BL, which stipulates the right to life and physical integrity, on Article 14 I BL, which guarantees property, as well as on Article 12 I BL, which protects professional freedom. Under aggravated circumstances, even Article 1 BL containing the right to human dignity might be invoked, which, in conjunction with Art. 2 I and 20a BL has been labelled as the ecological minimum standard of living by several scholars and been discussed by the Constitutional Court in its 2021 landmark decision. That decision particularly  underlined the importance of Article 20a BL and is likely to be used in many future cases. In light of Art. 20a BL the Court understood relevant fundamental rights as ‘intertemporal guarantees of freedom [that] afford the complainants protection against comprehensive threats to freedom caused by the greenhouse gas reduction burdens […] being unilaterally offloaded onto the future’ (BVerfG, 2021, para. 183). However, the Court reaffirmed what it had already stated in an earlier relevant decision concerning emission reductions under the EU emissions trading system (BVerfG, 2007): The legislator has a wide margin of discretion as to how to implement Article 20 a BL.

Remedies sought may take the form of a declaration of unlawfulness of the challenged national policy and the obligation to restore legal compliance (e.g. Family Farmers and Greenpeace Germany v. Germany), or an order to amend the challenged law (e.g. BVerfG, 2021).