2. Developments in Tort Law in Response to Climate Change

2.1 Negligence

The tort of negligence refers to a civil cause of action that depends on the plaintiff being able to demonstrate that they have suffered a legally recognised injury that was caused by the defendant’s lack of reasonable care in circumstances where the defendant had a duty to take such care. Negligence has been the basis for the two major tort-based climate cases in Australia thus far: the completed Sharma v Minister for the Environment^[1] (‘Sharma’) and the pending Pabai Pabai v the Commonwealth^[2] (‘Pabai’).

2.1.1 Duty of Care

In Sharma, a group of Australian children argued that the Commonwealth Minister for the Environment (the Minister) owed Australian children a duty to consider future harms to them in deciding whether to approve an expansion of the Vickery coalmine in New South Wales.^[3] If approved, the mine’s expansion was expected to increase coal extraction from 135 to 168 million tonnes (mt), generating a further 100 mt of Scope 3 emissions over the lifespan of the project. The Minister’s decision was pursuant to the Environment Protection and Biodiversity Conservation Act 1999 (Cth) (‘EPBC Act’).

Because the case related to future harms, the nature of the claim was unusual. Negligence is a damage-based tort; it depends upon injury to the plaintiff. The remedy sought usually relates to that damage — compensatory damages aimed at putting the plaintiff in the position they would have been had the tort not occurred. There have, however, been negligence cases in Australia where litigants have successfully sought injunctive relief to prevent harm that has not yet occurred but is anticipated to follow from a defendant’s breach of a duty of care.^[4] This was what the children sought in Sharma.

The key question for the Federal Court was whether the Minister owed the children the duty of care that they claimed. As a novel duty case (one that did not fall into established duty categories), this question had to be determined from first principles. The duty of care inquiry in negligence serves a gatekeeping function, setting normative boundaries around those to whom we are legally obligated to personally account to for our conduct, and those to whom we are not. While the decision of courts as to whether to recognise a novel duty is guided by precedent and principle, it has also been described as an exercise in value judgment, involving ‘questions of fairness, policy, practicality, proportion, expense and justice’.^[5] Further, it ties to the relational nature of tort law. A duty is not owed in the abstract. It is owed to specific persons, not ‘the world at large.’^[6] In this sense, ‘negligence in the air, so to speak, will not do’.^[7]

In determining novel duties, Australian courts apply the ‘salient features’ or ‘multifactorial’ approach, evaluating features of the present case that precedent demonstrates are relevant to the question of whether or not a duty of care arises. In Sharma, in the first instance, Bromberg J found the salient features of the case supported the plaintiffs. He held that a risk of future harms to Australian children was foreseeable to the defendant in light of the volume of emissions the mine expansion would contribute and the potential for climate ‘tipping points’, where even small contributions could trigger a 4 °C future world scenario.^[8] He also held that the specific risk of harm in question was within the Minister’s control, given that power to approve the mine expansion fell to her alone and notwithstanding her lack of control at other relevant causal points leading to harm.^[9] The children’s special vulnerability to risks created by the Minister and their special reliance upon the government to address a problem entirely outside their making were also central.^[10] The harms they face, Bromberg J held, ‘will largely be inflicted by the inaction of this generation of adults, in what might fairly be described as the greatest inter-generational injustice ever inflicted by one generation of humans upon the next.’^[11]

The Full Court of the Federal Court disagreed. Allsop CJ found four salient features in particular weighed against a duty of care. Those were that the claim exposed the Minister to a scope of liability that could not be adequately anticipated (indeterminate liability)^[12] and that the children lacked any special vulnerability or reliance upon the Minister, beyond the general political reliance we all have as Australians upon our government.^[13] He also held that the purported duty in negligence was incoherent with the Minister’s statutory duties.^[14] Unlike Bromberg J, Allsop CJ held that the EPBC Act is not principally concerned with protecting the environment, and the human communities relying upon it, but with managing the relationship between levels of government.^[15] But Allsop CJ’s primary concern was that in assessing whether the Minister had breached the purported duty of care, a court would be asked to scrutinise core governmental climate policy. This task, he argued, is ‘unsuitable for the Judicial branch to resolve in private litigation by reference to the law of torts and potential personal responsibility’.^[16]

Justice Wheelahan relied on similar considerations to Allsop CJ to reject the duty of care but also found that reasonable foreseeability of harm itself was not made out due to the tenuous causative link between the Minister’s decision and anticipated future harms.^[17] Finally, Beach J held that the relationship between the parties was simply not of a sufficiently proximate kind in the sense that is foundational to a duty in negligence. There was not, he held, the ‘requisite sufficient closeness and directness’ between the Minister’s exercise of her discretion to approve or reject the mine expansion and the effects of this on the children, in light of temporal, geographical and causal gaps between the two.^[18]

At first glance, the outcome in Sharma does not bode well for future negligence-based climate litigation in Australia. There are, however, reasons to remain optimistic. First, the science upon which the claim was pursued was not challenged by the Minister and was accepted by the courts. Second, the various reasons given by the judges to explain their decisions demonstrate the potential for reasonable minds to differ on the operation of specific negligence principles in the context of climate litigation. The Full Court was divided on a number of points and there are promising lines of argumentation within the reasons of even those judges that found against a duty of care that future litigants might adopt. Finally, there is evidence that the judges were alive to the need for negligence law to evolve. Justice Beach went so far as to suggest that negligence principles in Australia may well have ‘reached their shelf life’.^[19]

Some of the difficulties in Sharma reflected the prospective nature of the claim: the elements in negligence are interrelated and the contours of a purported duty of care to others are brought into sharper relief once harm has occurred. Without damage, a court lacks a critical lens through which to define and limit a duty of care and will thus be more conservative. The pending case in Pabai is thus one to watch. Pabai is a class action brought by two Indigenous leaders on behalf of Torres Strait Islanders for harms to their lands and their culture they argue result from Commonwealth failures on climate change.^[20] The plaintiffs in Pabai are seeking a declaration from the Federal Court that the Commonwealth owes a duty of care to protect Torres Strait Islanders from climate harms impacting them, their lands and their cultural practices, and a finding that it has breached that duty, together with injunctive relief to enforce the duty and damages.^[21] Unlike Sharma, the plaintiffs point to actual harms already being experienced in the Torres Strait as a result of rising sea levels and coastal erosion, as well as how those will worsen if steps aren’t taken. Those harms include damage to cemeteries and to traditional practices for growing food and gardening. Moreover, the claimants can point to specific legislation that shapes a unique relationship between them and the Commonwealth, which speaks to the plaintiff problem. Together, these factors may prove consequential.

2.1.2 Causation

The other element of negligence that will be particularly challenging for climate litigants is causation. Causation in negligence requires a court to find, on the balance of probabilities, that the defendant’s breach was a necessary condition of the plaintiff’s harm. While this does not require the defendant’s breach to be the only or direct cause of the plaintiff’s harm, in the ordinary case it does require that the plaintiff would not have been injured ‘but for’ the defendant’s breach.^[22] The burden is on the plaintiff to prove this.

Clearly, this test will be difficult to demonstrate in some climate cases, though not necessarily in all. For example, in Pabai one of the plaintiff arguments is that failures of the government to construct an adequate sea wall are the cause, in the traditional ‘but for’ sense, of specific damage to coastal areas due to erosion that it could anticipate.^[23] For climate harms tied in more complex ways to a defendant’s conduct, however, such as those that depend upon demonstrating a causative link to harm through a causative link to weather events, traditional approaches are inadequate. Yet climate change is not the first causatively complex scenario that tort courts have had to grapple with. In Australia, cases related to diseases caused by exposure to asbestos in particular (so-called toxic torts claims) have been important in this respect. As a result, alternative approaches to causation have developed.

The position of litigants in Australia in arguing causation in negligence-based climate cases is somewhat more tenuous than that of their peers in other common law countries. This is because Australian courts have so far not adopted the Fairchild line of argument that, in some circumstances, increased risk can satisfy cause. Developed in the United Kingdom, those principles provide that a defendant’s contribution to an increased risk of injury to a plaintiff is sufficient to satisfy causation in a negligence claim where multiple events may have caused the plaintiff’s injury but it is scientifically impossible to say which, in fact, did.^[24] If this is an appropriate way to characterise how climate science explains the causation of climate harms in a given case (perhaps, for example, in light of climate ‘tipping points’), then the lack of an ‘increased risk’ doctrine in Australia is significant. While causation was not directly at issue in Sharma, it was addressed at some length by some of the judges. Where they did, they suggest that to succeed the case would turn on an increased risk type argument.^[25] Whether the court got this right, however, can be challenged.^[26]

Despite the lack of an increased risk doctrine in Australia, our civil liability legislation allows for an alternative approach to causation in negligence, other than the necessary condition of harm test, when a court deems it appropriate. Emerging science on probabilistic and indeterminate causative pathways in the context of climate change and the harms it produces may provide a principled basis for adopting such alternative approaches.^[27] An existing alternative means of proving causation in Australian common law is the ‘material contribution to harm’ test. This approach allows that a material (more than de minimus) contribution to a harm will suffice in circumstances where the defendant’s breach is one of a few sources that have cumulatively brought about the plaintiff’s harm. In Amaca v Booth, for example, the High Court of Australia held that it was open to a trial judge to find that the claimant’s mesothelioma was caused by his cumulative exposure to asbestos from multiple sources over many years working as a brake mechanic, including from the brake products of the two defendants.^[28] In cases like this, causation is proven through demonstrating that a defendant’s breach was a material part of a set of causes that together were necessary to the outcome.^[29] This test may well be more appropriate than the increased risk test in some climate change cases.^[30]

2.2 Nuisance

Nuisance is concerned with unreasonable and substantial interferences to a person’s use and enjoyment of their land (private nuisance) or to a right common to the public (public nuisance). It is sometimes described as an environmental tort, as a complaint may relate to material or sensory impacts of noise, smells or other forms of ‘emission’ pollutants caused by industrial activities. Nuisance thus seems, on the face of it, to be particularly relevant to climate litigation.^[31] Despite this, nuisance has not been widely adopted as a climate litigation tool in Australia to date, though that might change. To be sure, nuisance has been the basis of a number of overseas climate claims, including by state and local governments in the United States^[32] and by Indigenous leaders in New Zealand^[33] against major industrial contributors to greenhouse gas (GHG) emissions. A claim in nuisance can avoid some of the challenges of a negligence claim. For example, requirements to prove fault on the part of a defendant in nuisance (in so much as it arises) may not be as onerous as in a negligence claim.^[34] Nor does nuisance require the plaintiff to establish a duty of care, and while the starting point for causation in negligence is the ‘but for’ test, in nuisance (especially public nuisance) the focus is on ‘the defendant’s creation of, or contribution to, a rights-infringing state of affairs’.^[35] That said, there are aspects of nuisance law that will be challenging for climate litigation, three of which are discussed briefly below.

A preliminary challenge is standing. Private nuisance is a proprietary tort, meaning a person can only bring a claim where they have an adequate interest in land to which their complaint relates. This may preclude many from using private nuisance to pursue climate justice. However, there are certain categories of claimants that we can anticipate might meet this threshold, such as coastal^[36] or First Nations^[37] communities whose lands are impacted by climate change. A private claim in public nuisance, by contrast, does not require a proprietary interest in land but it does require a person to show that they suffered special damage that is different to, or greater than, harm suffered by the public at large. This standing requirement has presented a hurdle in overseas public nuisance climate claims, in light of the anticipated widespread impacts of climate change. Bullock, however, argues that there is substantial judicial misunderstanding of the rule and that it is less of an obstacle to climate claims than generally believed.^[38]

Another challenge for nuisance-based climate claims reflected in overseas jurisprudence is non-justiciability, meaning the judicial view that the case raises matters for parliament and not the courts.^[39] While non-justiciability is not a formal element of nuisance in Australia, Emmanouil et al note that similar considerations are likely to be reflected in determinations as to whether an interference is ‘unreasonable’.^[40] Determining whether an interference is unreasonable involves a balancing exercise between the plaintiff’s and the defendant’s interests that draws on a range of considerations. It is defined by a ‘live and let live’ ethos that requires us to put up with a degree of discomfort demanded by our social interconnectedness. To demonstrate reasonableness, a defendant might argue that their impugned conduct (say, the extraction of coal or industrial GHG emissions) is a reasonable use of land, as reflected in governmental climate policy and its social value.^[41] Having said this, what is reasonable to a given place and time changes as society changes, and this kind of argument may have less purchase as coal extraction and GHG emissions become less socially defensible in the face of climate harms^[42] or where differentiated and disproportionate impacts on certain communities become more evident. Nuisance does not sanction some individuals subsidising the social utility of a defendant’s business for the benefit of others.^[43]

Finally, the defence of statutory authorisation may present a challenge. According to this defence, a person is not liable for an interference attributable to them where it is an inevitable outcome of their compliance with a statute. Much comes down to what is mandated or what is simply permitted by a statute, as well as questions as to whether more care could have been taken by a defendant, including whether to go ahead with authorised usages of land at all. While it is difficult to assess the likely success of this defence in the abstract, Emmanouil et al suggest that it may present a particularly potent defence for emissions from land used for coalmining activities authorised by statute.^[44] As with reasonable use, however, views on what due care under a statutory authority means are likely to evolve.

2.3 Other Torts

There is growing evidence that fossil fuel companies have been aware for decades that their products cause ‘globally catastrophic’ climate change.^[45] In the face of this knowledge, rather than sharing the information, altering business operations and supporting policy action, evidence is emerging of the extent to which companies have engaged in a ‘multi-decade disinformation campaign’ aimed at extending the lifespan of their business model.^[46] This behaviour suggests the potential relevance of the tort of deceit and of principles of civil conspiracy, in the style of earlier tobacco company litigation.^[47] While such a claim is likely to be challenging, in light of the high threshold to demonstrate deceitful (fraudulent) conduct and the need to link misrepresentation to personal damage, the approach may nonetheless be viable.^[48] Another type of disinformation that is emerging as we move towards a green economy and that may constitute a tort is corporate misinformation about green credentials; misrepresentations of this kind have been pursued in Australia as misleading and deceptive conduct under consumer laws.^[49]

A further issue that might arise in tort law due to climate change is the attempt to present a climate necessity defence to justify climate direct action in a civil trespass case. This defence has been tried in criminal trespass cases,^[50] but its traction in a civil law matter would be different in light of the different interests protected by tort and crime law, and their distinctive social functions.

Finally, there are questions as to how principles of proportionate liability may complicate climate litigation.^[51] Under civil liability legislation around Australia, where a plaintiff’s damage can be attributed to more than one wrongdoer, a defendant’s liability for that harm is limited to such an amount as a court considers just, having regard to the extent of their responsibility for loss. While this rule only applies to certain claims relating to property damage and economic losses, and not to personal injuries claims or intentional harm such as that caused by deceit, it raises challenging questions as to how a court will assess proportionality in light of multiple wrongful sources of climate harms.