International Law

In a landmark ruling, the International Court of Justice (ICJ) has confirmed that states are legally obliged under international law to prevent harm to the climate.

The ruling reflects a broader shift in attitudes towards climate change in the international community, particularly as pressure mounts for increased accountability and government action. 

For Australia, the ruling has significant implications, especially for its fossil fuel industry – emphasising that climate inaction is not only a political failure but a breach of international law.

What was the Issue?

The issue can be traced back to 2019, when a group of 27 law students from Vanuatu sought to break the deadlock on climate change action in the international community.

Seeking clarification on the legal obligations of states with regard to climate change, they eventually gained diplomatic support from Vanuatu’s government, which cultivated a successful global campaign for the ICJ to hear the case.

After the General Assembly adopted a resolution in March 2023, supported by over 130 countries, the ICJ was asked to give its advisory opinion. The Court was posed two central questions.

1. What are the obligations of States under international law to ensure the protection
   of the climate system and other parts of the environment from emissions of greenhouse gases for States and for present and future generations?
2. What are the legal consequences under these obligations for States where they have caused significant harm to the climate system and other parts of the environment, particularly with respect to vulnerable states and communities?

Key Findings

The court issued a clear and unanimous decision on the issue, affirming that states are bound under both treaty and international customary law to mitigate harm to the climate environment.

In making its decision, the court drew from a wide spectrum of international legal sources, including the UN Framework Convention on Climate Change (1992) and the Paris Agreement (2015).

It also drew from the no-harm principle – a central tenet of customary international law – and confirmed its application in the context of climate action.

The no-harm principle requires states to take appropriate measures to prevent, reduce and control the risk of environmental harm to other states, including the prevention of activities that may cause transboundary environmental damage. The Court held that Greenhouse gas emissions clearly fall within the scope of transboundary environmental harm, and therefore invoke the no-harm principle.

Finally, the ICJ considered various human rights instruments – finding that climate inaction may infringe a range of human rights, including the rights to life, health, and a clean and healthy environment. This was based on the relevance of intergenerational equity and the state’s obligation to consider the rights of future generations when crafting environmental policy.

Among the ICJ’s key findings:

• The 1.5°C goal is legally binding. States must employ measures consistent with the Paris Agreement and International law to comply with this temperature limit.

• Climate pollution isn’t just harmful: it’s unlawful. States must act diligently to limit greenhouse gas emissions in order to prevent harm to the environment.

• There are consequences. Full reparations may be provided to States harmed by the climate inaction of other States.
• NDCs must be credible and aligned with the best available climate science. A country’s climate targets must be capable of achieving 1.5°C, and wealthier countries will be held to a higher standard based on their historic emissions.
• Governments must regulate private polluters. States must ensure that regulatory and legal frameworks adequately regulate private corporations to control their emissions.

Why is it Important?

Although the advisory opinion lacks pragmatic enforcability and remedies for breaches of obligations remain limited, it still has significant potential to broaden the scope for climate action.

By setting clear expectations and standards for states, the Court has provided the international community with a normative framework to strengthen and develop their own domestic policy. The practical guidance provided by the opinion will also help to realign states with their international obligations, particularly as they pertain to the regulation of non-state entities operating within their borders.

As a whole, the ruling is a turning point for the future of climate accountability – elucidating that the moral duty of states to protect the climate exists alongside an equally important legal duty.

What Does it Mean for Australia?

Considering the significant legal dimensions of the ruling, it is important to analyse its impact through the lens of the law, particularly as it relates to Australia and its fossil fuel industry.

In its submissions before the ICJ, Australia argued that it had no historical responsibility for climate change action and that only the Paris  Agreement can address climate change. It also insisted that human rights agreements have no application in the context of climate change.

The ICJ’s decision repudiates Australia’s stance on both these matters. Instead, it imposes an obligation on Australia to limit the damage domestic companies are causing to the global climate – and reaffirms the possibility of litigation from any nation impacted by the country’s highly damaging fossil fuel activities.

International Responsibility 

Given Australia’s status as one of the highest per capita polluters in the world and its continued reliance on fossil fuel exports, the decision will likely open it up to a host of litigation from other states.

Already, potential legal challenges from Vanuatu seem imminent. Speaking to the ABC,  Vanuatu’s Climate Change Minister Ralph Regenvanu said that litigation was a serious option.

“According to the advisory the ICJ handed down today, Australia is committing internationally wrongful acts as it is sponsoring and subsidising fossil fuel production and excessive emissions,” he said.

“Australia is one of the major contributors to fossil fuel production. It’s the third-largest exporter of fossil fuels in the world. It’s a major contributor to emissions.

“It needs to align itself with the advisory opinion and cease this conduct that is contributing to emissions and start making reparations.”

If Australia is found liable by the ICJ in any potential legal action, then the consequences could include full reparations to injured states, including restitution, compensation and satisfaction.

Domestic Law

Although the ICJ’s opinion is not enforceable in its own right,t it may help facilitate a transformation of legal duties within Australia’s domestic law.

Prior to the release of the Advisory Opinion, the High Court found that no analogous duty regarding climate change existed in domestic law in the case of Pabai Pabai v Commonwealth of Australia (No 2) [2025] FCA 796.

The question for the Court to consider was whether the Commonwealth Government owes a duty of care to people of the Torres Strait Islands to protect them, their way of life, and the environment from the impacts of climate change.

Two Torres Straight Islander leaders put forward negligence claims on behalf of their communities, relying on the assumption that the Australian government owed them a duty of care to mitigate the impacts of climate change, such as rising sea levels and coastal erosion.

Whilst Justice Wigney recognised the impact of climate change on Torrens Straight Islander communities, and acknowledged that the Commonwealth had not given genuine consideration to the issue, he ultimately found that no Duty of Care was owed under the law of negligence as these are matters of government policy.

The reasoning in Pabai reflects the decision of the Federal Court in the Sharma case, and is indicative of the judiciary’s reluctance to recognise government responsibility for climate actions in the absence of statutory requirements.

However, the decision lies within a legal landscape that is still in its infancy and is largely contrary to the ICJ’s advisory opinion. Ostensibly, there is still a broad scope to reconcile the disconnect between domestic and international law, and the ICJ’s ruling will only serve to ameliorate that process.

Liability for Corporations

The Advisory opinion confirms that governments have a responsibility for private companies within their jurisdiction that are contributing to climate change. As such, they have an obligation to regulate the activities of private actors, which will likely result in much-needed changes to the regulatory framework. In this context, there is a broad scope for the Advisory Opinion to be invoked in litigation against large corporations as claimants consider the principles of international law to ascertain corporate compliance with climate-related duties.

Renewed Hope

In short, the ICJ’s ruling is a potentially transformative moment for international law – reframing the issue of climate change as one that is purely political, to one that is demarcated by an evolving set of complex legal principles. It reaffirms to all states that inaction around climate change is not only a moral failure but also a legal one, and that accountability is essential.

More broadly, the ruling serves to remind the international community of the ways in which collective action can be used to effect tangible change. The fact that the case stems from the activism of young students will empower future generations to harness their collective power and bring about change themselves.

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