The Australian climate litigation movement has recently made significant inroads into the field of negligence. In Sharma v Minister for the Environment (2021) (Sharma), the Federal Court held that the Minister for the Environment owes a duty to Australian children to take reasonable care when considering approval of a coal mining project being pursued by Vickery Coal Pty Ltd. This is because the greenhouse gas emissions from the project are expected to contribute to climate change and its related personal injuries to future generations.

This case can be understood as part of what has been labelled the ‘next generation’ of Australian climate litigation cases. Members of the Australian climate litigation movement are looking beyond the confines of environmental protection legislation to see how other areas of law may be developed to help address the emerging climate crisis. Among others, their sights are set on the field of constitutional law.

This is, in part, inspired by developments internationally. People across the globe have been seeking answers from their courts on what is implied or expressed within their respective constitutions that may be of assistance in combatting climate change. In Urgenda Foundation v Netherlands (2015), for instance, the Hague District Court drew on the Dutch government’s environmental protection obligations in constitutional law to help establish a governmental duty of care to its citizens to strengthen its greenhouse gas emission reduction commitments. In Ashgar Leghari v Pakistan (2015), the Lahore High Court held that the Pakistani government’s failure to implement its climate policies violated citizens’ constitutional rights to life, human dignity, property and information. At the time of writing, the plaintiffs in Juliana v United States of America (2016) (Juliana) are in the process of arguing that the public trust doctrine has an implied place in the United States constitution that would effectively restrict the Federal government’s ability to worsen climate change.

Australia does not have explicit environmental protection provisions in its constitution, such as provisions ensuring the right to a healthy environment, as several other nations have in theirs. Potential may lie, however, in deriving an implied protection in the Constitution to address the climate crisis. This may be premised on the fact that climate change poses a threat to the Australian constitutional system itself.

That is, while the future effects of climate change cannot be known with certainty, climate experts fear that its cumulative impacts in the long-term may result in nothing short of societal collapse in Australia and beyond. Such concerns have recently been heightened with the publication of the latest Intergovernmental Panel on Climate Change Report, which UN Secretary-General António Guterres refers to as a ‘code red for humanity’. Climate change, therefore, appears to hold the potential to significantly impair the operation of, if not completely destroy, the Australian constitutional system – a system ‘intended to endure for centuries’, as McHugh J has stated: Theophanous v Herald & Weekly Times Ltd (1994) at [8].

This may have profound ramifications for how domestic government action worsening climate change, such as government approval of new coal mines, is understood in Australian constitutional law. By contributing to bringing about climate change, this government action contributes to bringing about a serious threat to the Australian constitutional system. When government action poses a threat to this constitutional system, political means (such as parliamentary scrutiny or public debate) might be relied upon to confront this action. The existence of such a threat, however, may also provide the grounds for deriving an implied limitation from the Constitution to restrain such action.

The Melbourne Corporation doctrine, for example, is an implied constitutional limitation established to restrain the Commonwealth from passing laws that compromise the states’ autonomy. The High Court derived it to help protect the federal foundations of the Australian constitutional system: Melbourne Corporation v Commonwealth (1947) (Melbourne Corporation). Another example is the freedom of political communication, an implied constitutional limitation established to restrain the Commonwealth and states from taking legislative and executive action that unduly burdens people’s freedom of communication about government and political matters. The Court derived it to help protect the democratic foundations of this constitutional system: Nationwide News Pty Ltd v Wills (1992); Australian Capital Television Pty Ltd v Commonwealth (1992) (ACTV).

Along similar lines, a doctrinal argument can possibly be made for establishing an implied constitutional limitation restraining certain Commonwealth and state legislative and executive action worsening climate change. Such a limitation would help protect the system’s ecological foundations. I refer to this proposed implication as the ‘ecological limitation’.

The argument for the ‘ecological limitation’

In order to outline the possible doctrinal argument for the ecological limitation, attention must be paid to the High Court’s approach to establishing implications. The Court requires constitutional implications to be derived from the ‘text and structure’ of the document: Lange v Australian Broadcasting Corporation (1997)(Lange). The ecological limitation, if established, would be an example of a ‘structural’ implication. Such implications must be drawn from the Constitution’s words and, according to Mason CJ, can only be derived where ‘logically or practically necessary’ for preserving the ‘structural integrity’ of the Australian constitutional system: ACTV at [29].

The ‘text and structure’ based argument for deriving the ecological limitation starts with a prosaic observation. Namely, the Constitution’s text makes clear that the Australian constitutional system requires humans. They make up the ‘electors’, ‘judges’, ‘senators’ and others that run, and are served by, the Australian constitutional system: at ss 8, 9, 72. The Constitution’s text also makes clear that this constitutional system is not floating free from the physical realm but operates within a specific ecological site. This site is essentially the continent of Australia. This is evident in various provisions: the ‘Commonwealth of Australia’ is formed from the relevant ‘colonies’ situated across the Australian continent ‘including the northern territory of South Australia’; the ‘seat of Government of the Commonwealth’ must be placed ‘not less than one hundred miles from Sydney’; and so forth: at cls 3, 6 and s 125.

Thus, combining these two observations, the Constitution stipulates that humans must carry out their constitutional roles within the specific ecological site of Australia. It logically follows that damage to this site’s habitability has the potential to damage the structural integrity, if not existence, of the Australian constitutional system. Some standard of habitability in Australia, therefore, must be maintained. It may be viewed as ‘logically or practically necessary’ to restrain certain Commonwealth and state legislative and executive action worsening climate change in order to uphold this standard.

Responding to arguments against the ‘ecological limitation’

A deeper understanding of the ecological limitation can be gained by considering some of the main objections that it might attract. Consider government action similar to that in Sharma by way of example – government approval of a coal mining project. One objection may be that such a project does not singlehandedly bring about the climate crisis or, consequently, destroy the Australian constitutional system. This may lead to a conclusion that no domestic government action would be damaging enough to justify the application of the ecological limitation.

Judges, however, have increasingly rejected such arguments in climate litigation matters (including in Sharma: at [253]). They recognise that climate change is a ‘death by a thousand cuts’ problem and all substantial ‘cuts’ must be taken seriously. This is especially so given the tight ‘carbon budget’ (the amount of carbon that can be emitted before dangerous climate tipping points are reached) that now remains after decades of climate inaction.

Further, the High Court seems to formulate ‘structural’ implications in a manner conducive to this reality. Government action is not required to completely destroy the Australian constitutional system for it to be held in breach of such implications. A single Commonwealth law restricting certain political advertisements or a single Tasmanian law restricting protest sites, for example, were far from capable of causing such damage. Nevertheless, they were deemed in breach of the freedom of political communication in ACTV and Brown v Tasmania (2017) respectively. While these laws could not be linked to the wholesale destruction of the Australian constitutional system, they could be viewed as contributing to its compromising. In its conceptualisation of ‘structural’ implications, the Court appears sensitive to the ways in which the Australian constitutional system may be damaged in a partial or incremental manner.

Another objection may concern the economic and related benefits of a fossil fuel project. Such benefits, which presumably explain why the government is approving the project in question, must be taken into account. A resolution to this may be formulating the ecological limitation to include a proportionality component. This is how the countervailing benefits of government action ostensibly damaging this constitutional system have been addressed in the context of other areas of Australian constitutional law. This includes other ‘structural’ implications such as the freedom of political communication: Lange.

The precise operation of ‘proportionality’ in Australian constitutional law remains contentious. Generally speaking, proportionality analysis in the context of the ecological limitation would require judges to assess whether the government action in question strikes a proper balance between its (economic) benefits and (ecological) detriments. This may raise its own concerns. The judiciary weighing these competing factors with regard to a fossil fuel project may be viewed as being in conflict with its constitutional role. This is because judges may be viewed as lacking the sufficient skills, resources or democratic mandate for such politically-charged decision-making.

Several problems, however, exist with this position. First, such concerns have been raised against the use of proportionality generally as well as its application with regard to ‘structural’ implications specifically. In Cunliffe v Commonwealth (1994), for example, Dawson J warned that proportionality ‘invites the court to have regard to the merits of the law – to matters of justice, fairness, morality and propriety – which are matters for the legislature and not for the court’: at [25]. Despite these concerns, proportionality continues to be employed in Australian constitutional law and in the formulation of ‘structural’ implications.

Second, it is arguable whether this use of proportionality requires more ‘political decision-making’ that takes the judiciary beyond its capacities than the Court already accepts in its use of proportionality in the context of the implied freedom, the defence power, the implied nationhood power, and other areas of constitutional law. In these uses of proportionality, judges must make decisions in the realm of national security, economics, civil liberties and other complex, politically sensitive fields.

Third, ecological limitation matters are not monolithic. Some may present greater challenges than others with regard to judges’ capacities, which can be dealt with on a case-by-case basis. Judges may defer to the relevant government’s position on particular issues in the process of applying the ecological limitation where they consider it appropriate. If factual uncertainties regarding the number of jobs created or other economic bona fides of a fossil fuel venture are in dispute, for example, judges may opt to defer to the government’s assessment of these matters.  Such obstacles in the decision-making process can be handled in this manner, rather than rejecting the establishment of the ecological limitation on the whole.

Finally, at least some weight must be given to the ways in which the judiciary may be well equipped, if not better equipped, than those in the legislative and executive branches to assess the legitimacy of government action that worsens climate change. The primary aim of the proposed ecological limitation remains fundamentally judicial – protecting the Australian constitutional system from actions of the other branches that may impair it. The judiciary also has a better claim to impartiality than those who instigate the action in question and is not burdened by their institutional weaknesses, such as partisanship and influence from vested interests profiting from exploitation of natural resources.

This is not merely a theoretical point. These institutional weaknesses help explain, in practice, why the Australian government and governments worldwide have failed to adequately address climate change over the last three decades. Magistrate Judge Coffin (of the United States District Court) found such reasoning compelling in his determination that Juliana, discussed above, may proceed to trial. He stated:

[t]he intractability of the debates before Congress and state legislatures and the alleged valuing of short term economic interest despite the cost to human life, necessitates a need for the courts to evaluate the constitutional parameters of the action or inaction taken by the government (at 8).

Contextualising the ‘ecological limitation’

I examine the arguments for and against establishing the ecological limitation in more detail elsewhere. The challenges that the ecological limitation presents, however, are sure to be expected by the climate litigation movement. As one anonymous Australian lawyer, interviewed by Jacqueline Peel and Hari Osofsky, explains:

I take a long-term view [of] climate litigation. I really think we are like lawyers in Alabama in 1950 fighting for black civil rights or … lawyers at the early stages of cigarette and asbestos litigation, trying to establish a causal link between cigarettes and lung cancer. … [Y]ou get looked at like you’ve got two heads … . But the issues are so enormous and the science is so strong; it’s not like the problem is going away (at 1).

In the context of Australian constitutional law, such obstacles are also to be expected when deriving implications. The task of determining what is written in ‘invisible ink’ in the Constitution, as Aharon Barak describes implications, is an inherently difficult one (at 373). This is compounded when the implication in question places limits on government power in politically sensitive areas, as discussed above. The history of the High Court is littered with examples of such implications being met with substantial opposition and concerns of judicial overreach.

This history also demonstrates, however, that profound social or global changes have frequently formed the backdrop for deriving new implications. This is due to the fact that new circumstances have the capacity to shed light on dimensions of constitutional law that have not been previously considered and are not plainly evident from a reading of the Constitution’s words. The unique threat posed by communism during the Cold War, for example, formed the backdrop for establishing the implied nationhood power (or at least the postulate to it): Burns v Ransley (1949); R v Sharkey (1949); Australian Communist Party v Commonwealth (1951). The era of big (centralised) government and unprecedented expansion attempts by the Commonwealth during and after World War II, for another example, formed the backdrop for establishing the Melbourne Corporation doctrine. Profound social and global changes similarly form the backdrop for the ecological limitation. The unprecedented emerging threat of climate change serves as the catalyst for considering the establishment of this proposed implication.

Taking seriously the need to maintain the Australian constitutional system for future generations means taking seriously the threat climate change poses to it. The High Court’s derivation of the freedom of political communication, the Melbourne Corporation doctrine and similar ‘structural’ implications positions the Constitution as, in essence, a self-preserving document. The Constitution does not permit Australian governments to take action that tarnishes the Constitution itself. If it is accepted that climate change is (among other things) a constitutional problem, then it is important to interrogate the potential for constitutional solutions to it in the spirit of this self-preservation. The ecological limitation may be such a solution.

Dr Costa Avgoustinos is a constitutional law and administrative law academic at the University of Technology, Sydney (Law) and recent PhD graduate at the University of New South Wales (Law).

Suggested citation: Costa Avgoustinos, ‘The “Ecological Limitation”: Exploring the Implications of Climate Change for the Australian Constitution’ on AUSPUBLAW (22 September 2021) <>