Inadmissibility Decisions after KlimaSeniorinnen: Hope Remains for Müllner v. Austria as the Next Successful Climate Case before the ECtHR

In the shadows of the ICJ’s climate advisory opinion, Strasbourg has been busy with climate cases too – busy, mostly saying no. Published on 28 August 2025, the European Court of Human Rights (ECtHR) declared Engels and Others v. Germany, a follow-up to Germany’s Neubauer litigation, inadmissible. The decision leans heavily on the demanding victim-status test set in Verein KlimaSeniorinnen Schweiz and Others v. Switzerland and, for the first time, places notable weight on “personal adaptation”. It follows this spring’s inadmissibility decisions in De Conto and Uricchio, and sets the remaining hopes higher for one particular climate case with priority status before the ECtHR: Müllner v. Austria. This post outlines why, in my view, the Müllner climate case has the potential to become the ECtHR’s most promising post-KlimaSeniorinnen opportunity to affirm individual victim status, resist burden-shifting through “personal adaptation”, and require Austria to adopt an enforceable framework in light of its ongoing shortfalls, which could have potential implications for all EU Member States.

A wave of inadmissibility decisions in the KlimaSeniorinnen aftermath: Uricchio, De Conto and Engels

In KlimaSeniorinnen, the ECtHR’s first climate case in April 2024, the Grand Chamber found Switzerland in violation of Articles 8 and 6 of the European Convention on Human Rights (ECHR) on the grounds that Switzerland did not fulfil its positive obligations to adopt and effectively apply measures against foreseeable climate harms and that its courts did not meaningfully engage with the complaint (paras. 545, 636). At the admissibility stage, the Court admitted only the applicant association and rejected the individual applicants by setting what it called an “especially high” threshold (paras. 488, 527) for victim status to exclude actio popularis: applicants must (i) show individualised, high-intensity exposure to the adverse effects of climate change and (ii) a pressing need for individual protection due to the absence or inadequacy of reasonable measures to reduce harm, that is, that available public measures or reasonable personal adaptation would not avert the risk (paras. 487-488, 533). In fact, the Court has since clarified in the environmental case Cangi and Others v. Türkiye (No. 2), that these demanding admissibility criteria are confined to climate cases (para. 31).

Lately, this stringent bar has proved decisive in several climate applications. First, Carême v. France was declared inadmissible for lack of standing (paras. 80-88).
This spring, in De Conto v. Italy and 32 Others and Uricchio v. Italy and 31 Others, the Court first declined extraterritorial jurisdiction over the non-Italian respondents because the applicants resided in Italy, following its stance in Duarte Agostinho (see here and here). Secondly, the ECtHR found the applicants failed the KlimaSeniorinnen victim-status test as there was no convincing evidence of high-intensity personal exposure, no real and imminent risk to life, and no substantiated link between alleged health conditions (e.g., asthma) and climate change. Notably, both were issued by a three-judge Committee, not the Grand Chamber.

Now Engels adds a new stress point: “personal adaptation”. The case follows the Neubauer case of 2021 in which the German Federal Constitutional Court (BVerfG) held that the 2019 Climate Protection Act was incompatible with fundamental rights for failing to set sufficient provisions for emission cuts beyond 2030, burdening future freedoms under Article 20a of the Basic Law, and required Parliament to set clearer post-2030 pathways. Although the Act was amended (with a 65% emissions reduction by 2030 and climate neutrality by 2045), nine young applicants in Engels argued the revised Act still fell short of the Paris trajectory and violated Articles 2 and 8 ECHR. After the BVerfG declined to hear the case, the ECtHR, sitting as a three-judge Committee, held that the applicants’ submissions described climate impacts too broadly and lacked individualised, high-intensity risk, with no specific vulnerability or exceptional circumstances (para. 10). Interestingly, for the first time, the Court placed notable weight on the availability of adaptation measures in Germany and “reasonable” personal adaptation, by referring to KlimaSeniorinnen (para. 533). The Article 2 complaint was found to be incompatible ratione materiae since there was no “real and imminent” risk to life.

Risks of burden-shifting through “reasonable” personal adaptation

This approach raises several concerns to me. Resolving Engels in the Committee rather than the Grand Chamber sidestepped the chance to clarify the still-undeveloped, vague notion of “personal adaptation”. Without guidance on who can reasonably be expected to adapt, by what means, and how unequal capacities should be weighed, the focus risks shifting the burden from State obligations to individual resilience. Additionally, absent clarity on the evidentiary standard of available adaptation measures, States may point to generic, paper-level adaptation to defeat standing, creating a loop in which applicants are told to adapt unless they prove they cannot – yet they cannot make that showing without State-enabled measures (e.g. evidence of what adaptation exists, who can access it, and how it performs). This is circular. A Convention system that conditions climate protection on personal resilience will protect the resilient and leave the vulnerable exposed, who are unable to evidence ineffectiveness or unavailability of “reasonable” adaptation – especially when “reasonable” remains undefined. Some voices even question whether placing responsibility on applicants to avoid harm is compatible with the very purpose of a human rights protection system at all (see here and here). Precisely because adaptation is context-dependent, the Court’s supervisory role is particularly important. To avoid burden-shifting where applicants show concrete health impacts, I suggest that the Court should set clear criteria and assess whether measures are (i) available and accessible to the applicant, (ii) implemented and resourced in practice, (iii) effective in reducing the applicant’s risk, and (iv) responsive to unequal capacities. Once a prima facie risk is shown, the evidentiary burden should fall on the State to demonstrate that adaptation measures actually work for the person concerned and are “reasonable”.

Why Müllner v. Austria is different

Unlike earlier Strasbourg climate cases, I believe Müllner is different or to be more precise: “unmistakably individual”. The applicant, Mex Müllner, an Austrian with multiple sclerosis and Uhthoff’s Syndrome, suffers acute heat sensitivity: above 25 °C he needs a wheelchair, at 30 °C he depends on an electric wheelchair and outside assistance. Rising summer temperatures already restrict his daily life. He argues that Austria’s failure to adopt effective mitigation, while maintaining climate-harming incentives, breaches Articles 2, 6, 8 and 13 ECHR. After the Austrian Consitutional Court dismissed a complaint by over 8,000 individuals for lack of standing (the applicants were not addressees of the targeted aviation-friendly tax rules), Müllner filed an individual application with the ECtHR in March 2021.

After the Grand Chamber’s 2024 climate trilogy, the Court granted the case priority status under Rule 41 of the Rules of the Court in June 2024, citing its importance, the urgency of the questions raised, and the applicant’s alleged deterioration in health due to global warming.

With a minority of 22% of pending applications receiving priority status in 2024, Müllner’s designation highlights the case’s significance. The ECtHR further admitted 18 national and international institutions and experts as third-party interveners to address complex issues, including the UN Special Rapporteurs Elisa Morgera and Astrid Puentes Riaño. The written phase concluded in May 2025, and now with both parties having submitted their observations, the case currently awaits judicial deliberation.

What distinguishes KlimaSeniorinnen, De Conto, Uricchio and Engels from Müllner is evidence. In KlimaSeniorinnen, the individual applicants failed to qualify as victims under Article 34 ECHR because even though they might be particularly vulnerable (para. 531), they showed neither a critical medical condition nor a direct link between rising temperatures and their health issues, such as asthma (paras. 533-534). In Engels, the applicants were unable to demonstrate any specific vulnerabilities or exceptional circumstances indicating a future individual risk (para. 10). Similarly, in Uricchio and De Conto, the Court held that the applicants provided no medical documentation to substantiate their allegations of physical and mental health impact (both paras. 14).

By contrast, Müllner can tie his heat-aggravated disability directly to increasing temperatures and the absence of reasonable personal adaptation measures. Whereas the Swiss claim relied on group-level statistics about older people’s vulnerability (paras. 529, 65-66) and insufficent evidence of individual harm, Müllner presents medically verified, person-specific evidence of current and foreseeable harm. This concreteness aligns with the Court’s high admissibility bar and makes his victim-status claim particularly strong.

Moreover, the “personal adaptation” emphasis seen in Engels sits uneasily here. Expecting an individual with a heat-aggravated disability to resolve the issue through self-help or by relocating from Austria to a country with lower average temperature would hollow out Article 8. Especially since it would entail detaching him from his settled life, relationships, and medical and social support systems. Meaningful adaptation is relational and often State-enabled, as it requires accessible cooling, targeted health planning, early-warning systems, building and workplace standards, and social support. Thus the victim standing requirements could indeed be met.

Austria’s climate protection gap and EU targets

Austria offers a textbook backdrop. The “current” Klimaschutzgesetz, Climate Change Act, sets goals and coordination mechanisms but no binding post-2020 targets, no quantified carbon budgets, no enforcement or corrective mechanisms. The new climate law draft presented by Environment Minister Totschnig (ÖVP) does not remedy this weakness. It is roughly half the previous version’s length, drops international climate finance, judicial remedies and the Citizens’ Climate Council and replaces binding duties with a non-binding “roadmap”. Most strikingly, it omits the 2040 climate-neutrality commitment. This regressive turn could matter for Müllner, since in KlimaSeniorinnen, the ECtHR particularly found an Article 8 violation because Switzerland lacked a coherent domestic framework, with critical gaps such as the absence of a carbon budget or national GHG-limitation pathway and had failed to meet past emission-reduction targets (para. 573). Moreover, drawing on scientific evidence, Müllner submits that adherence to the 1.5°C limit would significantly improve his overall well-being (para. 60), a standard Austria appears to struggle to meet. In KlimaSeniorinnen, Switzerland (despite later hesitation on implementation) could at least point to additional measures taken during the proceedings. By contrast, Austria’s proposal appears to anticipate missing EU targets by preparing to purchase foreign certificates for non-compliance. In fact, the Austrian Environment Agency recently alerted that with current policies and measures, Austria will miss the EU 2030/2040 targets by 9 million tonnes CO₂e and called for a stronger climate law.

Nonetheless, Austria’s submission to the ECtHR in Müllner leans on compliance with the EU’s 2030/2050 targets and argues that this is sufficient to meet human rights duties. By adopting such defence, Austria effectively turns Müllner into a potential test case on the adequacy of EU climate policy itself. This matters because the ESABCC, an independent scientific body, reports that a 90% EU emissions cut by 2040 is 1.5°C-compatible. Yet the decision on the Commission’s proposal has been delayed after several States, including Austria, pushed to shift it from the September Environment Council to the late-October European Council, where unanimity could stall or block agreement. The proposal still requires approval from Parliament and Council and with the EU due to submit its 2035 interim target to the UN by 24 September, the rescheduling could be seen as a delaying tactic.

Instead of tightening policy, Austria seems to take another step back from climate protection. Austria’s domestic legal architecture intensifies the problem. Under Article 140(1) B-VG, Federal Constitutional Act, individuals can only challenge norms that directly affect them, leaving legislative omissions effectively unreviewable and creating a protection gap for those harmed by inaction. This gap is precisely what Müllner asks Strasbourg to name – with a real prospect of success regarding a violation of Articles 6 and 13 ECHR.

Outlook: Strasbourg’s role, separation of powers and wider implications

Ultimately, Müllner could be strong on admissibility and on the merits, in my assessment. On admissibility, the prospects of the case are promising. Because the applicant’s medically documented, heat-triggered disability cannot be managed through self-help or State enablement, the Court could find that “reasonable” adaptation offers no meaningful protection. Müllner could thus expose the limits of Engels’ “personal adaptation” and his condition may demonstrate present, individualized harm sufficient to secure victim status.

On the merits, the case fits the KlimaSeniorinnen template: Austria lacks a coherent, enforceable framework against foreseeable heat risks, making an Article 8 violation distinctly plausible. Given the applicant’s heat-triggered disability at ordinary summer temperatures and reduced life expectancy, Article 2 is credibly engaged under the “real and imminent” risk standard. Regarding procedural rights, Austria’s formalistic rules insulating legislative omissions from review effectively close domestic courthouse doors, making the Articles 6 and 13 claims compelling: if omissions cannot be tested domestically, access to court and an effective remedy are, in practice, illusory.

The wider international legal landscape also supports this prediction. The recent ICJ climate advisory opinion (see here, here, and here) – non-binding but likely persuasive in Strasbourg – frames clear State duties to prevent climate-related harms, treats omissions as legally relevant, identifies 1.5°C as a meaningful benchmark, and views continued fossil-fuel subsidies with skepticism (see here). Austria, still channeling about €5.7 billion a year into fossil-fuel subsidies while oil, gas, and coal supply two-thirds of its energy, has lagged on these fronts.

Admittedly, even a strong judgment would face the practical political challenges illustrated by Switzerland after KlimaSeniorinnen. Subsidiarity gives States room and Strasbourg will not dictate climate statutes or carbon budgets. Austria’s hesitant legislature, procedurally inaccessible judiciary and a weak draft climate law make Müllner as much a separation-of-powers case as a climate one. Critics warn that “judicializing” climate policy risks bypassing democratic debate and, as Judge Eicke cautioned in his partly dissenting opinion, may tie up authorities in further litigation, potentially delaying effective climate action (Eicke, p. 257, paras. 69-70). In fact, in KlimaSeniorinnen the Court recognised that primary responsibility lies with domestic political branches but stressed that judicial oversight complements democracy, that State policy affecting Convention rights is a matter of law the Court cannot ignore and that the risk of short-termism in climate governance adds justification for review (paras. 412, 420, 450). The Court also circumscribed its role: its mandate is confined to the Convention, with a narrow margin on States’ commitment, aims and objectives and a wide margin on the means (paras. 411, 543). I find the Court’s reasoning convincing, because where omissions foreseeably harm identifiable people, requiring an enforceable framework is not overreach but the Court’s basic duty to enforce minimum rights standards. On this footing, Müllner does not ask Strasbourg to make climate policy, it asks the Court to require an enforceable, reviewable framework and effective remedies consistent with Articles 2, 6, 8 and 13 ECHR.

Whatever the outcome, the beauty of climate litigation is that cases raise public awareness, can spark further climate litigation and rights-based debates, increase long-term political pressure and can even lead to legislative change in Austria and beyond. Although many expected Duarte Agostinho – a complaint against 33 States – to fail, it still moved the conversation simply by existing. Müllner can do the same, foregrounding vulnerability and strengthening protection for people with heat-sensitive conditions and disabilities. Furthermore, Austria, unlike Switzerland, is bound by EU climate targets, which raises the question whether mere (alleged) compliance with EU requirements suffices to discharge States’ human rights protection duties, or whether they must go further, especially where EU benchmarks fall short of scientific necessity. This could lead to broad implications for all EU Member States.

In the end, Müllner is narrower and stronger on admissibility than recent failures and implies a core point: “personal adaptation” should not become a shield for States but a reason to protect those who cannot adapt without them. If a heat-sensitive applicant is not a climate change “victim”, who is?