Climate Change and Human Health: Who Should Bear the Cost?

Contributed by Pouya Dabiran-Zohoory

As early as 2001, there has been international recognition of the human impact on climate change. The Third Assessment Report of the Intergovernmental Panel on Climate Change stated: “There is new and stronger evidence that most of the warming observed over the last 50 years is likely to be attributable to human activities”.

Earth’s natural greenhouse effect has been amplified by human actions which increase the concentration of energy-trapping gases in the lower atmosphere.  The international community has demonstrated awareness of the problem and motivation to work towards a potential solution. Various treaties, including most recently the Paris Agreement, commit to rapid reduction in greenhouse gas (“GHG”) emissions to keep global average temperatures below a 1.5°C rise from pre-industrial levels.

Many different methods have been proposed, and in some cases implemented, to combat this problem – from incentive-based solutions such as sustainable investment policies, to market-based economic systems such as carbon tax or cap-and-trade programs. The main objective of these systems is to reduce GHG emissions.

While these efforts are promising, it is also important to acknowledge that even with drastic emission reductions, there are ongoing consequences of the GHGs already emitted. Specifically, one of the consequences of climate change is an adverse impact on human health. Some direct effects on health cited by the World Health Organization include extreme heatwaves and weather events, and air pollution. Some indirect effects include reduced food production and supply, and increased vector-borne diseases. Who should be held responsible for these serious consequences, and how?

While these efforts are promising, it is also important to acknowledge that even with drastic emission reductions, there are ongoing consequences of the GHGs already emitted

The Difficulties of Compensating Health Victims of Climate Change

The difficulty of finding justice in these scenarios is rooted in multiple issues including the vast number of people impacted by climate change in diverse ways, the interjurisdictional nature of climate change, the vast number of actors who contribute to climate change (both directly and indirectly), and defining what justice would even mean in this context.

To illustrate issues tied to a climate event with multiple actors and victims, let’s look at an example still fresh in our minds: hurricane Irma and its death toll of 102 people. The storm destroyed over 90 percent of the buildings and vehicles on the island of Barbuda. Estimates for its impact on the world economy range from dozens of billions of dollars to hundreds of billions of dollars. Importantly, its destruction will also be a source of health problems like increased mosquito-borne diseases, increased respiratory problems, increased carcinogens like ammonia and benzene in the environment, and increased bacteria leading to skin infections.

Irma In 2017, hurricane Irma swept across the Caribbean and southern United States, causing severe damage || (Source: Flickr // Hurricane Irma 67 )

The Issue with Causation

Although scientists are uncertain whether climate change will lead to an increase in the number of hurricanes, warmer ocean temperatures and higher sea levels are expected to intensify their impacts.  Therefore, it is not possible to assert that climate change and global warming caused hurricane Irma. This presents difficulty in a legal case where a victim of a similar storm sues for compensation under a tort, given the need to prove both factual and legal causation. If a statutory tort were to be created which only required proof of, for example, “involvement in an activity known to contribute to climate change and global warming”, both legal and factual causation would not be an issue.

However, it would seem an unnecessary burden on court systems to have the vast number of people affected by hurricanes bring forward claims for compensation. This is especially true with the looser causation requirements in a statutory tort, since one of the justifications for tort law – individual justice – requires a finding of responsibility attributing blame to the wrongdoer. Given the difficulties of finding individual justice by attributing responsibility, and the increasing need for compensation for climate change victims, it would seem much more efficient to set up a climate change victim-compensation scheme such as the no-fault regime in Quebec for motor accidents. In this scheme, victims of climate change related losses, such as hurricanes, could apply to such a fund to be compensated for their loss. All actors who participate in an activity known to contribute to climate change would be required to pay into the fund.

Determining the Extent of Responsibility for Each Actor in a “Climate Change Victim Compensation Fund”

We must identify the actors involved and the extent of their contribution to the problem in order to determine the relative responsibility of actors.

It seems impossible to adequately measure how much one individual emitter, such as a single company, contributed to an event such as a hurricane, given that it is impossible to define to what extent climate change contributed to the onset and severity of that hurricane. Our best estimations would be rooted in some contribution index tied to the percentage of overall GHG emissions. This can be modeled after a program like the GHG Protocol.

However, it is important to note that, like hurricanes, many effects of climate change involve merely increasing the frequency and severity of already existing phenomena. It would seem unjust to have the contributors to such a fund paying for the entire cost of certain events if the occurrence of those events was not caused by climate change. It would also make sense to have the State contribute to the fund since the State has historically funded climate related losses, even before the aim was to attribute responsibility through compensation. Additionally, the State holds some responsibility for these losses given that its policies determine the legality, incentives, and disincentives for climate change contributing activities. Lastly, since the State is the representative of citizens and residents in its territory, and consumer decisions drive global warming to an extent, this would also represent our shared contribution to climate change as individuals.

While climate science has some uncertainties, it can help inform the compensation framework. These policy decisions should integrate an interdisciplinary understanding of victim suffering. For example, climate science can help shed light on which losses are climate related by exposing the different pathways through which climate change can affect human health. Economic analysis can help quantify more accurately the financial losses suffered by a victim of a climate change related event. On the other hand, anthropology and sociology could shed light on the magnitude of losses suffered to a group of people’s way of life through the loss of traditional lands due to rising water or drought, which can in turn be tied to health consequences for communities. All these considerations could be under an umbrella analysis that further adds the degree to which the natural disaster was exacerbated because of climate change.

While a compensation scheme may seem no different than the implementation of a carbon tax regime, it is important to remember that the purpose of such a fund would be to compensate victim loss related to climate change. The purpose of a carbon tax regime is to quantify the unaccounted cost of a carbon footprint, and the tax collected is put to a variety of uses, including but not limited to victim compensation.

Drought Communities suffer consequences to their way of life and health due to droughts and loss of land from climate change || (Source: Flickr // EU Civil Protection and Humanitarian Aid Operations )

The Interjurisdictional Nature of Climate Change

Lastly, it is important to remember that climate change is a global phenomenon. Legal and political boundaries do not define or constrain the impacts of climate change. Responsibility for climate change related losses should not be constrained by jurisdiction either. It would seem harsh to require Antigua and Barbuda to pay to rebuild its country themselves when the responsibility for a catastrophe like Irma rests at the world’s feet. While inter-jurisdictional issues complicate compensation and attributing responsibility, it is important that the international community not only concern itself with reducing global warming, but also with developing adequate and concerted efforts to compensate for the inevitable impacts climate change will have on humanity – including those related to human health. A fund such as the one proposed above could eventually be adopted into an international scheme to help better capture responsibility for climate change related losses.

Pouya Dabiran-Zohoory is a Senior Online Editor with the McGill Journal of Law and Health, with a keen interest in sustainable development, specifically with a focus on climate change and its effects on human and animal health. He holds a Bcomm in law and business from Ryerson University. Since he joined the Faculty of Law at McGill University in 2016, he has taken an interest in how the common law, civil law, and regulations address health issues.

Saadati v Moorhead, 2017 SCC 28

Contributed by Pouya Dabiran-Zohoory


Canadian Tort law has developed to require four broad criteria to satisfy a claim in negligence: 1) A duty of care which is owed to the plaintiff, 2) a breach of that duty which, 3) leads to damages, and 4) a legal and factual causal relationship. Historically, the common law has been hesitant to recognize non-physical injury as compensable, with additional requirements for proving psychiatric injury. Canadian common law has been shifting away from this requirement, with both the Mustapha v Culligan (Mustapha) decision in 2008 and the recent decision of Saadati v Moorhead (Saadati) in 2017, discussed here. Saadati has made it less onerous for plaintiffs to prove “psychiatric” injury.

The main issue in Saadati was defining “mental injury” in a claim of negligence, and deciding how that can be determined to exist in court. More specifically, the issue was whether a claim of mental injury must conform with what an expert witness from the medical community has defined as a psychiatric injury, or whether the determination necessarily belongs to the trier-of-fact.

Facts and Judicial History

The plaintiff, appellant to the Supreme Court of Canada (SCC), was involved in a car accident when his tractor-truck was struck by a vehicle driven by the defendant, the respondent. Although the appellant’s truck was damaged, he seemed uninjured. This accident was the second in a series of five accidents that the appellant suffered between the years of 2003 and 2009. The appellant sued the respondents, the three parties involved in the first three accidents, for non-pecuniary damages and past income loss, before suffering the two later accidents.

At the Supreme Court of British Columbia, the respondents collectively admitted liability for the accidents but took the position that the appellant did not suffer any damage. The trial judge concluded the appellant had not suffered any physical damages, but had suffered “psychological injuries, including personality change and cognitive difficulties” based on testimonies of friends and family of the appellant. The British Columbia Court of Appeal decided that the appellant had failed to prove he had suffered a medically recognized psychiatric or psychological illness or condition, and therefore no injury, holding that such illness or condition must be demonstrated by “expert medical opinion evidence”.


The court began the analysis with a look into how the common law has historically viewed negligently caused mental injury. The judgement outlined the early common law’s “suspicion and sometimes outright hostility” toward such claims. The court showed how this skepticism continued into the past century by highlighting that mental injury was not compensable unless accompanied by physical injury. This, along with further barriers to recovery outlined in common law cases surrounding classes of victims and different types of proximity, were used to show the how difficult recovery has been in common law jurisdictions globally.

The court differentiated Canadian common law developments by citing Mustapha as the leading authority for the requirements to recovery for mental injury which held them to be no different than the “criteria applicable to any successful action in negligence”. The court held that the additional barriers to recovery for mental injury weren’t “based on legal principle, but on policy […] founded upon dubious perceptions of, and postures towards, psychiatry and mental illness in general: that mental illness is subjective or otherwise easily feigned or exaggerated; and that the law should not provide compensation for trivial matters”.

The court took issue with the premise that to compensate for mental injury, a plaintiff would need to obtain relevant expert testimony from the medical field as proof that they have suffered a “clinically diagnosed, recognizable psychiatric illness”. The court emphasized that to confine compensable mental injury to conditions identifiable with these diagnostic tools is suspect as a matter of legal methodology, and that the law is not concerned with accurate diagnoses, but rather with “symptoms and their effects”.

Responding to potential criticisms of the judgement leading to indeterminate liability, the court emphasized that the framework for negligence – particularly the proximity analysis in the duty of care component – will satisfactorily contain potential liabilities. In a transsystemic fashion, the court drew a comparison to Québec Civil law which allows compensation for “moral” injury under article 1457, to show that liability can still be contained.

The court also took issue with treating mental injury and physical injury as distinct under the law. The concern was that requiring a claim of mental injury in negligence to be classified as such in the medical community, but not requiring the same condition for physical injury claims, would lead to “less protection [for] victims of mental injury” and “for no principled reason”.

Having said this, the court was cognizant of the difference in nature between mental and physical injuries – that the latter is more readily apparent than the former. In discussing this, the court made clear that even without requiring expert testimony to prove mental injury, the courts will still only compensate for mental injury which “rises above the ordinary annoyances, anxieties, and fears that come with living in civil society”.

Lastly, the court was very clear in maintaining that expert testimony can still be helpful in determining whether or not mental injury has occurred, by determining, for example, how seriously the plaintiff’s cognitive functions were impaired. The court even went so far as to say that not adducing relevant expert evidence to assist the triers-of-fact can run the risk of damaging plaintiffs’ cases. Nevertheless, the court reiterated that, while expert testimony may help a claimant prove the existence of mental injury, it is not required as a matter of law.

The court found the trial judge to have been correct in their application of the law, and found that mental injury had occurred even without the existence of expert testimony.


The court’s primary concern in Saadati seemed to be the abdication of judicial responsibility in cases of negligence causing mental injury. Specifically, the court repeatedly mentioned how classification becoming a necessary component of the law of negligence would be problematic.

It is unclear in the judgement, however, why it is not possible to take into account expert testimony regardless of whether the expert believes that the plaintiff’s injury falls within a specific classification under diagnostic lists such as the Diagnostic and Statistical Manual of Mental Disorders (“DSM”) and the International Statistical Classification of Diseases and Related Health Problems (“ICD”) which were mentioned in the case. The court’s concern with these diagnostic lists not always being at the edge of scientific development in the field are reasonable. However, if this is the primary concern, it is unclear why an expert cannot still be required to inform the deliberation over whether psychiatric injury has occurred, based on that expert’s understanding of the current state of knowledge. Justice is important, and therefore it is equally important that there not be a miscarriage of justice based on faulty assumptions, which the court itself emphasized earlier in the case.

It is possible that the court wished to expand the scope of compensation for recovery of mental injury to include not only psychiatric harm, but also pure emotional harm, which the courts have historically not allowed compensation for, unless accompanied by physical injury. This isn’t objectionable from the perspective of redefining what constitutes justice in a case of negligence.

However, even if the courts intend to treat psychiatric and pure emotional injuries as the same under the umbrella of “mental injury”, how will the courts differentiate between mental injuries which rise “above the ordinary annoyances, anxieties, and fears that come with living in civil society”, and others which do not? As Dr. Stephen Smith notes, it could be problematic to conflate emotional harm with psychiatric harm, since the Anns-Cooper test for duty of care developed in Cooper v Hobart is not designed to limit liability based on the nature of the injury.

Perhaps using the term “mental harm” instead of “mental injury” would be helpful in alleviating some confusion. The court specified that they are concerned with “symptoms and effects”. An injury leads to symptoms and effects which cause harm to an individual, and so the true justiciable question may be whether the plaintiff suffered mental harm rather than a mental injury, which is a question a trier-of-fact may be better able to address without assistance from a medical expert. This is because the question would focus on how the plaintiff has been negatively affected, rather than diagnosing the injury leading to those effects.

Nonetheless, the precedent set by this case may help alleviate access to justice concerns for plaintiffs who cannot afford experts but have suffered very real mental harm, for which they should be compensated.

Pouya Dabiran-Zohoory is a Senior Online Editor with the McGill Journal of Law and Health, with a keen interest in sustainable development, specifically with a focus on climate change and its effects on human and animal health. He holds a Bcomm in law and business from Ryerson University. Since he joined the Faculty of Law at McGill University in 2016, he has taken an interest in how the common law, civil law, and regulations address health issues.