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Achieving Justice through Science

Updated: Sep 15, 2021

Event Attribution and Loss and Damage Compensation

By Rupert Stuart-Smith

A glacial lake in Peru. Melting ice raises the lake's volume and increases the likelihood of major flood outbursts.

The small native village of Kivalina, Alaska is being dumped into the ocean. Its shoreline is being rapidly eroded as sea levels rise and much of the sea ice, which has historically protected the village from the ocean, has melted. Kivalina is disappearing off the map and, according to its residents and their lawyers, is doing so as a result of climate change. So, in 2008, this village of 374 took 24 major coal, oil and gas producers to court on the grounds that they are responsible for this damage, both as a result of their greenhouse gas emissions and their coordinated misleading of the public on climate science. The court dismissed Kivalina’s case for a number of reasons, including a lack of a strong link between the actions of the defendant companies and the erosion damaging the village. Similarly, an earlier case (Comer v Murphy Oil USA, Inc.) which sought compensation for damages resulting from Hurricane Katrina (alleged to have been exacerbated by climate change) was also dismissed. Again, a key factor in the dismissal was that the tenuous link to climate change was insufficient to demand financial compensation. Following this unsuccessful start to climate litigation, what does the future hold for the victims of climate change seeking compensation for its costs?

These trailblazing climate litigation suits raise two important questions. Firstly, should the victims of the impacts of climate change be able to successfully sue those responsible for climate change? Or, as would those affected by ‘hard luck’ events which cannot be attributed to climate change, should they simply rely on the generosity of wealthy nations and aid agencies? Secondly, who are these victims of climate change: can science draw strong links between climate change and losses, sufficient to be accepted as causation in the law?

There is a clear difference between events which are the result of climate change and those which are not, in terms of who has a responsibility to compensate those impacted. Those responsible for greenhouse gas emissions should be held liable for the costs this imposes on others. This is particularly the case as it is often the world’s poorest and most vulnerable to the impacts of climate change who are most affected, despite having contributed the least to it. For example, the winter of 2015-16 was one of the worst droughts in northern Ethiopia in more than 50 years and left over 10 million people requiring humanitarian relief. One study holds climate change responsible for reducing rainfall by 16 percent, yet Ethiopia’s contribution to climate change is essentially negligible, responsible for only 0.02 percent of global emissions in 2010.

The destruction caused by climate change is the result of the decisions of the world’s biggest emitters. Therefore, according to Henry Shue, Professor Emeritus at Oxford University, the big emitters have a responsibility to compensate those who have been harmed by what they have done. Ultimately, climate change has left many of the world’s poor as victims of forces beyond their control. If this injustice is to be addressed, the development of a successful means of compensation for the damages of climate change is needed.

The costs of climate change

Extreme weather, of course, has always happened. However, if emitters’ liability for damages is to be established, the costs of climate change (and not simply of natural disasters) must be quantified. But what are the impacts of climate change? Some, such as Professor Mike Hulme at Cambridge University, argue that in today’s climate-changed world, no weather event can be a purely natural ‘act of God’. Clearly, human activity has influenced the climate system and it is within an atmosphere altered by our greenhouse gas emissions that all weather occurs.

However, it is not the case that climate change inevitably makes any given event more damaging: some weather events, such as storms resulting from polar lows, may become less frequent or impactful with climate change. In such instances, those responsible for climate change cannot reasonably be held liable for resultant damages. Therefore, assuming that all weather events have been impacted by climate change is insufficient for providing the attribution required for establishing legal liability or any robust intergenerational institution which can address damages resulting from climate change.

The rapidly developing field of weather attribution provides a means by which the costs of climate change can be quantified. By determining the extent to which the risk of a given event happening has changed as a result of human activity (see Watson, this issue), the influence of climate change can be assessed for specific events and those responsible for greenhouse gas emissions can be held liable for their effects. With these tools at hand, the bills for climate impacts can be redirected to those responsible for the costs. This opportunity to achieve justice is one which science, international negotiators and the law should not miss.

Achieving justice

There is an existing global framework for addressing loss and damage issues: the largely ineffective Warsaw International Mechanism for Loss and Damage associated with Climate Change Impacts (WIM). But the WIM does not establish whether loss and damage should refer exclusively to those impacts which can be scientifically attributed to climate change (or to climate-related events in general), nor does it make any specific demands for financial compensation. The lack of provision for financial compensation is a consequence of the uncompromising demands of developed world parties, such as the U.S., E.U., Canada and Australia, who have refused to support any mechanism through which they might be required to pay out to those suffering as a result of the means by which they obtained their prosperity.

The fact that the WIM falls under the United Nations Framework Convention on Climate Change (UNFCCC), whose mandate concerns human interference with the climate system, suggests that the WIM should deal with the losses and damages resulting from human induced climate change, which should be determined scientifically. In recent papers, scholars such as Rachel James and Christian Huggel have argued that the failure of the international community to use scientific knowledge to identify the impacts of climate change is partly responsible for the lack of an effective mechanism for compensation for the impacts of climate change. Even if scientific attribution studies are not a requirement for loss and damage compensation, they certainly have an important role to play in developing a more constructive policy and justice discussion.

In a 2014 paper, Rachel James and collaborators argued that current limitations in modelling and observational data restrict attribution studies to a limited number of events, which means that loss and damage mechanisms cannot rely exclusively on attribution science. This is certainly the case for tropical cyclones, which may result in huge damages, but which are very challenging to model and therefore to attribute. Past attribution studies have been predominantly constrained to well-understood phenomena like heatwaves, typically in developed countries in which extensive climate data is available. As the most damaging impacts of climate change typically affect the developing world, for whom establishing the burden of proof through scientific attribution may be financially and technologically infeasible, this is clearly an issue. In some cases the precautionary principle may need to be applied and in the future developments in modelling and increasing computing power will expand the potential for attribution science to be used in the law.

Event attribution and climate litigation

In a legal setting, claims for compensation for the costs of the impacts of climate change require evidence of harm caused as a result of greenhouse gas emissions. Lack of clear evidence of harm has been a successful counterargument raised by defendants in past climate litigation cases. As early as 2004, Allen and Lord noted that attribution would be vital for successful climate litigation. Yet 14 years on, attribution science has yet to be used in a legal case to establish polluters’ liability, nor have cases demanding compensation for damages resulting from climate change yet been successful. In a recent paper published in Nature Geoscience three lawyers argued that scientific attribution could identify human influence on events previously considered to be ‘acts of God’, thus establishing tort liability and clearing a major obstacle to the success of climate litigation. By connecting greenhouse gas emissions to their consequences, achieving restorative justice through compensation becomes possible.

A perceived challenge to the use of attribution studies in the law is that they are necessarily probabilistic rather than deterministic. We can never say that an extreme event was caused by climate change, as it could have occurred in a world without human interference with the climate, although likely with a much lower probability. However, Sophie Marjanac and colleagues argue that this does not reduce the potential for the use of attribution science in liability cases. In the UK, past legal proceedings considering epidemiological evidence have determined that a doubling of risk is sufficient to render synonymous ‘increasing the risk’ and ‘causing the damage’. Therefore, as Thornton and Covington argue in Nature Geoscience, probabilistic methods of attribution can establish sufficient causal connection in legal circumstances.

However, with a large group of actors responsible for greenhouse gas emissions, no one company has individually doubled the risk of a given event occurring. Who, then, is responsible? Thornton & Covington suggest that the courts can simply apportion costs of damages attributable to climate change in proportion to an individual firm’s greenhouse gas emissions. For example, German utility company RWE is the subject of a current lawsuit demanding compensation to avoid damage from a glacial lake outburst flood in Huaraz, Peru. The plaintiffs in this case argue that the 34-fold increase in lake volume since 1970 has made a devastating flood imminent, that this is the result of climate change, and that the implementation of protective infrastructure is required. If the court in this case were to rule that this was indeed the result of climate change and that RWE is liable to pay compensation for these costs, it would be appropriate for RWE to pay 0.47 percent of the costs of protecting the town, as the company is responsible for 0.47 percent of historical greenhouse gas emissions.

As I write this, the 4 million residents of Cape Town are just weeks away from running out of water. Although the role of climate change in this emerging humanitarian crisis has yet to be quantified, events like this are becoming increasingly frequent. As the impacts of climate change accumulate, the demands for compensation from those most responsible for greenhouse gas emissions will only grow louder.

In the context of the crisis of justice arising as a result of the impacts of climate change, surely the courts will not fail to provide relief for damages caused by, and attributable to, climate change?


Rupert Stuart-Smith is a DPhil candidate at the University of Oxford where his research focuses on climate change litigation and attributing climate change damages to individual emitters of greenhouse gases. His current research also spans sustainable finance and climate and glacier modelling.

This piece orginally appeared in Issue I (Spring 2018). Rupert's research on the risk of glacial floods in Peru was recently published in Nature Geoscience.

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