Customary law development for climate goals

There it is! The ICJ Advisory Opinion was put into action, with one of the first concrete examples of how it's being used in domestic courts. Last week, in 𝘓𝘩𝘰'𝘐𝘮𝘨𝘨𝘪𝘯 𝘷. 𝘊𝘢𝘯𝘢𝘥𝘢, the Canadian Federal Court became one of the first to engage with the Opinion to assess the scope of Canada’s climate obligations and how international law interacts with domestic law. Although the Court acknowledges in the decision that the Opinion is not binding on states, it does refer to “key principles that may affect state conduct” that are outlined in the Opinion, which “may have significant legal implications in the Canadian context”. Here’s how the Federal Court approached it: ▶️ The Court acknowledged the persuasive authority of the ICJ Opinion, particularly its emphasis that states’ duty to protect the climate system is also grounded in customary international law and human rights obligations. ▶️ It clarified that direct enforcement of the Paris Agreement or UNDRIP is not justiciable in Canadian courts (it has a dualist approach to international law). Only domestic statutes implementing these obligations can be challenged constitutionally. In other words, international obligations can inform interpretation but cannot create standalone rights enforceable in Canadian courts. ▶️ The Court stated that customary international law could, in principle, provide a basis for a novel common law claim, but plaintiffs must show evidence of general state practice and opinio juris (the belief that a practice is legally obligatory). Importantly, the Court left open the possibility for novel claims based on customary international law to proceed to trial, emphasising that “motions judge[s] must err on the side of permitting novel but arguable claims to proceed to trial”. ▶️ The Court also stated that international law can guide how courts interpret domestic rights, such as Section 7 of the Charter (life, liberty, and security of the person), when environmental harms are at issue. Even if international law cannot create enforceable obligations, it shapes the standards against which Canada’s domestic climate measures are evaluated. ▶️ The Court carefully separated obligations owed internationally (to other states or the global community) from obligations domestically enforceable. Alleged violations of the Paris Agreement or UNDRIP could potentially be considered internationally wrongful acts, but domestic courts are not the forum to adjudicate them directly. ▶️ Importantly, the Court left open the possibility for plaintiffs to amend their constitutional complaint to better align with international law or domestic statutes. This gives claimants a chance to reframe arguments on international customary law, for example. #ClimateLitigation #ClimateLaw #ICJ

Today marks a major milestone. The International Court of Justice (ICJ) has ruled that States have a legal obligation to take all necessary measures to limit global warming to 1.5°C. This marks a pivotal moment for international environmental law and the global climate justice movement. In its Advisory Opinion, the ICJ found that this obligation is based on UN climate treaties, human rights law, the law of the sea, and customary international law. It also recognised that the Convention on Biological Diversity informs climate obligations and that a duty to cooperate applies to all States. The Court also clarified that the content of Nationally Determined Contributions (NDCs) is not left entirely to States’ discretion. Instead, States must act with due diligence to reflect their highest possible ambition in each successive NDC, in accordance with Article 4.3. The ICJ has issued its opinion following months of deliberations and submissions from States and international organisations, including IUCN. Last year, I had the privilege of being part of the team that delivered IUCN’s statement before the Court in The Hague, emphasising that the climate crisis is not only a crisis of rising temperatures but also a crisis for humanity and nature alike – with profound implications for human rights. I want to particularly thank the IUCN World Commission on Environmental Law, Prof. Dr. Christina Voigt, and Dr Francesco Sindico, who have been key in driving IUCN’s role in these historic proceedings. This Advisory Opinion is a crucial step forward as we continue to drive impactful, practical action on the ground to deliver climate justice and safeguard our collective future. IUCN’s participation in this Advisory Opinion is notable, drawing upon legal and scientific expertise and underscoring IUCN’s unique role in ensuring that law, science, and nature work hand in hand to address the climate and biodiversity crises. Strong legal frameworks are powerful tools for hope, accountability, and transformation. They are essential for securing a just and sustainable future for people and nature. As the global authority on the state of nature, IUCN urges all States to strengthen their commitments and accelerate action. This is the moment to strengthen our collective resolve and deliver on the legal obligations now made clear. Learn more about this landmark Advisory Opinion here: https://lnkd.in/ebrC6AxY

Today, the International Court of Justice (ICJ) delivered its long-awaited advisory opinion on States’ obligations in respect of climate change—an extraordinary and historic moment for international climate law. This is the first time the ICJ has squarely addressed climate change, and the result is a powerful affirmation that States have binding legal duties to prevent climate harm—not only under climate treaties, but across the full spectrum of international law. Here are 11 major takeaways from the opinion so far (with more analysis to come): 1️⃣ The ICJ rejected the idea that only climate treaties apply. Instead, it confirmed that human rights law, the law of the sea, customary international law, and other environmental treaties also govern climate obligations. 2️⃣ These duties apply to all States, including those not party to climate treaties, regardless of development status or historical emissions. 3️⃣ States must prevent significant harm to the climate system through stringent due diligence, taking into account science, risk, and capabilities. 4️⃣ Cooperation is not aspirational—it is a core legal duty under both treaty and customary law. 5️⃣ The ICJ confirmed that States have a binding obligation to prepare, communicate, and maintain ambitious and evolving NDCs under the Paris Agreement. 6️⃣ The “highest possible ambition” standard is not left to States’ discretion—they must do their utmost to contribute to the 1.5°C goal. 7️⃣ States can be held liable for failing to regulate private actors whose emissions contribute to climate harm. 8️⃣ The Court emphasized that a clean, healthy, and sustainable environment is essential to the full enjoyment of human rights—and that States must integrate these obligations when implementing climate and environmental treaties. 9️⃣ The ICJ acknowledged that climate harm results from multiple States and actors, but each State can still be held individually responsible for its contribution. 🔟 Climate treaties do not displace the rules of State responsibility—breaches still trigger legal consequences. 🔁 Perhaps most strikingly, the Court affirmed that States responsible for climate-related wrongful acts may be required to provide reparations—including restitution, compensation, or satisfaction. This affirms the role of international law in redressing climate harm, beyond political negotiations. 📚 There is much more to unpack, and I’ll be sharing additional reflections soon. 📝 To support broader dialogue, we’re launching a blog symposium on the opinion hosted jointly by the Sabin Center for Climate Change Law’s Climate Law Blog and Verfassungsblog, with contributions from legal experts around the world. Stay tuned! https://lnkd.in/eVKeDdDj

The International Court of Justice finally delivered its much-anticipated advisory opinion today in an almost 2 hr long pronouncement. The ruling can be termed as not just symbolic but holds substantive legal jurisprudence with respect to international environmental law and state obligations in general. A few observations based on hearing the pronunciation are: First, the ICJ reaffirmed that States have obligations under customary international law to prevent significant transboundary environmental harm, including in the context of climate change, and must exercise due diligence in doing so. Second, the duty to conduct environmental impact assessments where there is a risk of significant climate-related harm is a binding procedural obligation under international law. Third, Climate obligations are erga omnes: all States have a legal interest in their observance, and breaches can be invoked by any State, not just those directly affected. Fourth, State responsibility is engaged where acts or omissions contribute to significant harm to the climate system, triggering duties of cessation, non-repetition, and reparation, including compensation. And fifth, states may be held internationally responsible for the conduct of private entities if they fail to exercise due diligence in regulating, supervising, or preventing private activities that result in significant harm to the climate system. A more detailed assessment and its implications can be done once the judgment is uploaded. Shared India's submission before ICJ in my earlier post today.

𝗧𝗵𝗲 𝘄𝗼𝗿𝗹𝗱𝘀 𝘁𝗼𝗽 𝗜𝗻𝘁𝗲𝗿𝗻𝗮𝘁𝗶𝗼𝗻𝗮𝗹 𝗖𝗼𝘂𝗿𝘁 𝗼𝗳 𝗝𝘂𝘀𝘁𝗶𝗰𝗲 (𝗜𝗖𝗝) 𝗵𝗮𝘀 𝗱𝗲𝗹𝗶𝘃𝗲𝗿𝗲𝗱 𝗮 𝗹𝗮𝗻𝗱𝗺𝗮𝗿𝗸 𝗹𝗲𝗴𝗮𝗹 𝗼𝗽𝗶𝗻𝗶𝗼𝗻: "A clean, healthy and sustainable environment constitutes a human right" On 23 July, the ICJ unanimously declared: 🔸 States have a legal duty to protect the environment 🔸 Failure to cut emissions may breach international law 🔸 Climate inaction could result in reparations This is the first time the ICJ has addressed climate change. The Court concluded that environmental degradation jeopardises the enjoyment of fundamental human rights for health, water, food and housing. This makes climate protection a legal obligation, not a political preference. The ruling matters because: 🔸 It reframes climate stability as a human rights issue, enshrined in customary international law. 🔸 It affirms that governments must act now not merely promise future action. 🔸 It opens the door to climate litigation against states that fail to act, particularly those enabling fossil fuel expansion. 🔸 It strengthens legal tools available to domestic courts and civil society. 𝗪𝗵𝗮𝘁 𝘁𝗵𝗶𝘀 𝗺𝗲𝗮𝗻𝘀 𝗶𝗻 𝗽𝗿𝗮𝗰𝘁𝗶𝗰𝗲: While the ICJ’s opinion is advisory and not binding, it is authoritative and likely to influence judicial decisions worldwide. It affirms that international environmental law imposes obligations of due diligence, prevention, and cooperation, with potential consequences for failure, including legal redress. It does not compel action but it arms campaigners, lawyers, and policymakers with powerful legal arguments to press for faster, deeper change. The real impact will depend on what happens next: 🔸 Will governments translate this opinion into national law? 🔸 Will courts cite it in climate lawsuits? 🔸 Will international negotiations reflect this new legal baseline? 𝗪𝗵𝗼 𝗹𝗲𝗱 𝘁𝗵𝗲 𝗰𝗵𝗮𝗿𝗴𝗲? A coalition of Pacific nations, led by Vanuatu, supported by 130+ countries, brought the case forward. As Vanuatu’s climate minister said: “This is a milestone moment for climate justice.” 𝗠𝘆 𝗧𝗮𝗸𝗲 This ruling is a significant inflection point in the global climate response. It places legal weight behind what climate scientists, frontline communities, and Indigenous peoples have said for years: 𝗖𝗹𝗶𝗺𝗮𝘁𝗲 𝗷𝘂𝘀𝘁𝗶𝗰𝗲 𝗶𝘀 𝗻𝗼𝘁 𝗼𝗽𝘁𝗶𝗼𝗻𝗮𝗹. But the real work is only beginning: 🔸 Governments must now align national policy with legal obligations, not just voluntary targets. 🔸 Businesses need to treat litigation risk as material, not theoretical. 🔸 Sustainability leaders should embed this new legal reality into risk models, board strategies, and stakeholder engagement. #ClimateJustice #HumanRights #Sustainability #ClimateLaw #EnvironmentalGovernance #ICJClimateRuling Source: https://lnkd.in/e6tzd6tr UN News: https://lnkd.in/eQF-_m3U ___________ 𝘍𝘰𝘭𝘭𝘰𝘸 𝘮𝘦 𝘰𝘯 𝘓𝘪𝘯𝘬𝘦𝘥𝘐𝘯: Scott Kelly

Many super important issues raised in the landmark climate judgement by the International Court of Justice (ICJ). 🔴 The ICJ recognizes that the 1.5 °C target (the Paris Agreement target) is "the scientifically-based consensus target under the Paris Agreement." This makes it way harder for states to legally justify policies that do not meet this target and push the world towards 2°C or worse. 🔴 Even countries that have not signed climate agreements such as Paris (blink blink) are bound to contribute to the fight against climate change. "Customary obligations are the same for all States and exist independently regardless of whether a State is a party to the climate change treaties" (par. 315). 🔴 WOW moment for fossil fuel phase-out: "Failure of a State to take appropriate action to protect the climate system from GHG emissions — including through fossil fuel production, fossil fuel consumption, the granting of fossil fuel exploration licences or the provision of fossil fuel subsidies — may constitute an internationally wrongful act which is attributable to that State. " (par. 427) #EndFossilFuels now! 🔴 Climate refugees: The ICJ points out that "States have obligations under the principle of non-refoulement where there are substantial grounds for believing that there is a real risk of irreparable harm to the right to life". (par. 378). This means no pushbacks for people from countries hit by intensifying disasters due to climate change, when there are serious reasons to believe that there's a real risk of irreparable harm to the right to life. This is binding for all states party to the ECJ, regardless of whether they have signed the Paris Agreement and other climate agreements. 🔴Obligation to regulate emissions by private actors: The Court explains that "the Court observes that the obligations it has identified under question (a) include the obligation of States to regulate the activities of private actors as a matter of due diligence. Therefore, attribution in this context involves attaching to a State its own actions or omissions that constitute a failure to exercise regulatory due diligence. In such circumstances, the question of attributing the conduct of private actors to a State does not arise." This is an extremely important point, as it affects any attempt at greenwashing by businesses that do not actually contribute to limiting global warming (par. 428). ➡️ ICJ advisory opinion of 23 July 2025: https://lnkd.in/dr2BmhpX ➡️ Statement by WWF Climate & Energy: https://lnkd.in/dqkHNkpN

Earlier this week, the International Court of Justice issued a historic Advisory Opinion confirming that States have binding legal obligations under international law to address #climatechange — not only under treaties like the #ParisAgreement, but also under customary international law. For governments, lenders, and developers across Africa and the MENA region, this marks a legal turning point, not just an environmental one: - Climate inaction may now give rise to State responsibility, including reparation and financial compensation. - Failure to regulate private actors (such as developers, polluters, and emitters) can be treated as a breach of a State’s due diligence obligations. - Climate obligations are now recognised as owed to the international community as a whole — meaning that any State may be held accountable under the relevant climate change treaties. In rapidly expanding markets like #Egypt, this opinion introduces a new legal lens for #infrastructure and #energy #development: > Governments will need to review their project approvals, licensing regimes, and subsidy structures through a climate risk filter. > Developers and financial institutions will need to anticipate legal exposure for environmental harm. > Regulatory clarity and alignment with international legal standards will be essential to attracting sustainable finance. I look forward to seeing in the months and years to come how this will shape the approach of lenders, regulators, and energy professionals to climate and infrastructure in #emergingmarkets. I sincerely hope it will not lead to cold feet on industrial expansion — but rather, drive a more credible and sustainable pathway to development. https://lnkd.in/d-2ju_Zi

International Court of Justice clarifies State obligations in respect of climate change    On 29 March 2023, the General Assembly of the United Nations (UNGA) adopted resolution A/RES/77/276 in which it requested the International Court of Justice (ICJ) to give an advisory opinion on “the obligations of States in respect of climate change”. Earlier this week, a unanimous ICJ delivered its opinion. It clarified that States have binding obligations under specific international treaties (for example, United Nations Framework Convention on Climate Change), international customary law, and human rights law, to ensure protection of the climate system. Failure to meet obligations in this respect may constitute an internationally wrongful act, triggering State responsibility. Remedies for breaches may include full reparation to injured States in the form of restitution, compensation and satisfaction, provided that the general conditions of the law of State responsibility are met, including that a sufficiently direct and certain causal nexus can be shown between the wrongful act and injury.     For a summary of the advisory opinion: https://lnkd.in/eUvCmr_j.    For the full advisory opinion: https://lnkd.in/eWQe3KUH.    For more information about this request for an advisory opinion: https://lnkd.in/eDaENWBg.  (https://lnkd.in/eXd5Pq2J) 

🌍 Landmark ICJ Opinion Confirms Legal Duty to Act on Climate – A Turning Point for Climate and Financial Governance On 23 July 2025, the International Court of Justice (ICJ) issued a unanimous advisory opinion—its first on climate—declaring that states have binding legal obligations under customary international law, human rights law, and treaty law to address climate change. The opinion was requested by the UN General Assembly in March 2023, led by Vanuatu and supported by over 130 states. 🔍 Key Conclusions: States must mitigate, adapt, cooperate internationally, and regulate emissions with due diligence. This is not optional, but a legal obligation grounded in climate and human rights law. The 1.5 °C target is a legal benchmark: national climate commitments (NDCs) must reflect science-based thresholds, not be left to political discretion. Activities like fossil fuel production, licensing, subsidies, and regulatory failure may now constitute internationally wrongful acts, triggering state responsibility for harm to the climate system. The Court confirmed that scientific attribution of harm is feasible, opening the door to interstate legal claims, loss‑and‑damage reparations, and broader accountability. The opinion also affirms climate-displaced people’s rights, non‑refoulement obligations, and the continued statehood of small island nations, even amid sea-level rise. ⚠️ Pending General Assembly Action While legally authoritative, the ICJ opinion is advisory and non-binding. It does not require formal “approval,” but may be acknowledged or reinforced through a General Assembly resolution—expected during a future UN or climate summit. Such a move would shape the opinion’s political weight ahead of COP30 and beyond. 🧭 System-Wide Implications for Finance and Institutions This ruling realigns the boundaries of national climate responsibility and financial system accountability: ✅ Climate inaction becomes legal default risk. Fossil fuel-related investments now conflict with established state duties. ✅ Litigation risk spans sovereign and private finance—as attribution science improves, carbon-heavy portfolios face growing legal exposure. ✅ Paris alignment is no longer just strategy—it’s a legal imperative. Risk frameworks, disclosures, and fiduciary models must evolve. ✅ It strengthens climate-aligned financial infrastructure—from transition finance to ESG tools, blended capital, and rights-based impact. ✅ By integrating customary law and human rights, the opinion sets a precedent for how finance defines duty, accountability, and equity. This is more than a legal milestone—it’s a systemic inflection point. Our task is to translate this legal clarity into structural financial change—aligning capital with resilience, justice, and long-term value. #ClimateJustice #ICJ #ParisAlignment #SustainableFinance #HumanRights #EnergyTransition #CustomaryLaw #JustTransition #ClimateRisk #SystemsChange #EBRD

𝗖𝗟𝗜𝗠𝗔𝗧𝗘 𝗜𝗡𝗔𝗖𝗧𝗜𝗢𝗡 𝗜𝗦 𝗡𝗢𝗪 𝗔 𝗟𝗘𝗚𝗔𝗟 𝗪𝗥𝗢𝗡𝗚 𝘐𝘊𝘑 𝘙𝘶𝘭𝘦𝘴: 𝘚𝘵𝘢𝘵𝘦𝘴 𝘊𝘢𝘯 𝘉𝘦 𝘏𝘦𝘭𝘥 𝘓𝘪𝘢𝘣𝘭𝘦 𝘧𝘰𝘳 𝘊𝘭𝘪𝘮𝘢𝘵𝘦 𝘏𝘢𝘳𝘮 On 23 July 2025, the International Court of Justice (ICJ) released its long-awaited Advisory Opinion on the Obligations of States in respect of Climate Change — a document that may well redefine the legal landscape of global climate action. ⚖️ ♻️ Requested by the UN General Assembly, this Advisory Opinion represents the first ever unanimous interpretation of international law by the ICJ on climate change. It affirms that States have binding obligations under international law — through treaties, customary law, and human rights principles — to act on climate change for present and future generations 𝗛𝗲𝗿𝗲 𝗮𝗿𝗲 𝗺𝘆 𝘁𝗼𝗽 𝟱 𝘁𝗮𝗸𝗲𝗮𝘄𝗮𝘆𝘀: ▪️ Climate treaties are enforceable: The Paris Agreement and related treaties are not just diplomatic ambitions; they carry binding obligations for States to act diligently and progressively. ▪️Customary international law matters: Even outside treaties, States are obliged to prevent significant environmental harm, including from activities of private actors under their jurisdiction. ▪️State responsibility is real: Failure to act — or omissions — can now constitute internationally wrongful acts with legal consequences. ▪️Science meets law: The Court acknowledges that attribution science can establish causal links between emissions and harm, empowering affected States to seek redress. ▪️Obligations erga omnes: All States have a legal interest in upholding climate protection, reinforcing the notion of shared but differentiated responsibility. 👥 𝗪𝗵𝗼 𝗯𝗲𝗻𝗲𝗳𝗶𝘁𝘀 𝗳𝗿𝗼𝗺 𝘁𝗵𝗶𝘀? Small island developing States. Least developed nations. Future generations. Climate litigators. And yes — sustainability professionals like us. This opinion bolsters global efforts to operationalize climate justice and accelerate ESG accountability. This is a vital resource for legal scholars, policymakers, climate litigators, and sustainability professionals. It reinforces that climate inaction is no longer just unethical — it is unlawful. 👏 🤝 Let this be the clarion call for meaningful, coordinated, and enforceable climate action. #planetaryhealth #planetaryboundaries #sustainability #ClimateAction #carbonfootprint #NetZero #ClimateEmergency #SDG #ESG #GHG #netzero #ICJ #ClimateJustice #ClimateLaw #StateResponsibility