Litigation has long been considered an important tool to hold companies and governments to account on environmental matters, and climate change is no exception.
Carroll Muffett, president and chief executive of the Washington-based Center for International Environmental Law (CIEL), sees it in a historical context: “The world needs to transform in ways that politics alone isn’t capable of achieving. If you look back over social justice movements over history, from civil rights to marriage equality, over and over again, where politics breaks down, law can break through.”
But when ENDS tried to write a feature on this subject in 2013, it hit a brick wall; nothing exciting is happening in this space was the standard response, action is a long way off. One experienced but dejected lawyer said to call again in 50 years’ time.
The mood is now completely different. In the intervening three years the political landscape has shifted, new options for using the law have been considered and tested, legal precedents have been set, and the hopes of people trying to drive action through the law have been reset.
So what has happened? When CIEL was first set up, it began looking at how international law could be used to hold the US accountable for climate change. “There are a lot of challenges to doing this,” says Muffett. “While we explored those sorts of international tools we increasingly recognised that the real power in the law lies in individual plaintiffs, communities or even entire states that are affected by climate change.”
So action began to focus on using tort law to compensate individuals who had lost out in the climate change equation. In a successful tort – a civil claim against someone who unfairly caused you harm – compensation is generally awarded for past loss and damage. In theory, courts could award financial damages or grant an injunction against similar future behaviour.
But this approach had limited success. Kivalina, an Inuit community in Alaska, tried to sue oil and gas major ExxonMobil in 2008, but a court held that regulating emissions was a political rather than a legal issue and damages could not be claimed.
There was also a growing sense of unease among campaigners that such cases did not have enough impact and could only be taken by people with the financial means and resources to do so – often not those most affected by a changing climate.
The remaining cases tended to be taken by protestors against particular projects, with fracking a particular lightning rod in the UK. Although most of these were not strictly climate change suits, they regularly used climate as part of their argument in court.
These types of cases are still happening – in just the past few months formal legal proceedings at the High Court have begun against the UK government’s decision to grant permission for fracking in Lancashire and action has been threatened against Heathrow expansion. And damages cases continue to be taken up (see map). 
Changing face of litigation
What has changed is that litigation has deepened and broadened; a wider variety of cases are being taken by different kinds of claimants against different kinds of defendants, and the evidence available to support their arguments has improved. Climate change is now cropping up in commercial, planning, tort, contract and trust law, human rights cases and administrative law such as judicial review. The result is that it is no longer a purely environmental issue but one that potentially affects every aspect of civic and personal life.
This is an international phenomenon. Kristin Casper, a lawyer working on Greenpeace’s Canadian climate justice and liability project, says there has been a “real blossoming” of cases outside the US. “In the last couple of years, it’s gone from a theoretical, scholarly discussion to something that’s real and that the courts are an important platform on.”
This shift is largely in response to legal and scientific developments. “Courts including the US Supreme Court have recognised that climate change is real and caused by human action,” says Muffett. “The question of climate change and responsibility for it is justiciable – something that the courts can address. These are huge milestones and mean that these fundamental questions of ‘can climate change get into the courts’ have already been answered.”
The science of climate change has hugely improved, so much so that it can be attributed to individual extreme weather events. Muffett points in particular to the case of Peruvian farmer Saúl Luciano Lliuya (see map, above). “One of the powerful things about his case is the scientific rigour with which the potential impacts and the links to climate change have been documented. Here we have a case where a community of plaintiffs can prove climate change is the specific source of particular harm to them.”
But problems remain. Key to these is how you draw a satisfactory link between the international phenomenon of climate change and harm caused to an individual or a group, and who that harm should be attributed to.
Navraj Singh Ghaleigh, a lecturer in public law at Edinburgh Law School, notes that many environmental lawyers are used to taking pollution cases, where a clearly identifiable source leaves a trace and has a specific impact. “It’s all so localised that, even if that locality is the boundary between the US and Canada or the Upper Nile and the Lower Nile, the chain of causation is still relatively easy to trace. But who emits CO2? Everybody, all the time and we’ve been doing it for centuries. It doesn’t matter where any given unit of CO2 is emitted, it has a global impact.”
This is a problem because, to bring a successful case under tort law, a direct link must be proved between the defendant’s conduct and the claimant’s loss.
Dr Friederike Otto, a senior researcher at the University of Oxford’s Environmental Change Institute, works on the science of extreme event attribution. She says the evidence will never be able to show that a certain extreme weather event would have been impossible without anthropogenic climate change. “That’s not because the science is not good enough, it’s just because every extreme event is unique. They each have multiple causes, we don’t have perfect observations or models, and we don’t have counterfactuals.”
But it is still useful. Otto says the most likely way this evidence could be used in court would be if it showed that anthropogenic climate change has at least doubled the risk of an event occurring.
The doubling-of-risk test is an alternative method of proving causation from the world of epidemiology, in which the claimant succeeds if they can show that their exposure to something doubled the risk which they would otherwise have had of developing the condition for which they seek damages. “That would be the threshold when the increase is so large that it is a game-changer and could be used in tort law,” says Otto.
The doubling effect has not yet happened uniformly across the world, and the scientific evidence is better in some cases than others. The impact of climate change on ocean acidification, for example, is much clearer than its effect on flooding. And in developing countries it is often very hard to find good quality observations of climate data. This matters, because while a court may accept the concept of anthropogenic climate change in general, it will still want local evidence to back up a particular event.
But the impacts of climate change are growing, and the scientific evidence is constantly improving - so the effect may yet be seen in a legal argument.
The next barrier is one of attribution – who should a claimant pursue? A defining moment for this was the completion of Rick Heede’s Carbon Majors project in November 2013, which mapped out how much CO2 had been created from products made by the world’s biggest coal, oil and gas companies.
The project, which has since been updated and peer reviewed, now accounts for about two thirds of all fossil fuel CO2 since production began.
This does not answer the question of which fossil fuel company a claimant should choose to pursue – and a defendant may argue that they should only be made liable if the rest of the industry is as well.
But the work has nonetheless given potential litigants robust figures for attributing responsibility for anthropogenic climate change to particular organisations, and various groups and individuals are considering using them in Canada, Germany, the US and the Philippines.
Heede is independent but collaborates with a number of organisations and clearly wants his work to be useful. “If you’re going to hold a corporate to account,” he says, “you have to have some data as to what their impact is.”
While the data’s applicability under tort law is still being debated, it is seen as increasingly useful for climate change cases being pursued through different legal regimes.
Muffett notes there are many systems in which you can hold fossil fuel companies accountable on a strict liability standard, and the question arises in other regimes too. One of things CIEL has examined is the question of product liability and the failure to warn in the context of oil. “This is really important because it recognises that everyone involved in moving a product to market has a responsibility if they’re aware of some risk associated with their product,” he says.
The case of ExxonMobil
A key example is ExxonMobil, which is the subject of legal action by two US attorneys general and its own investors (see map) – and these are not just polluter pays cases.
“The role of Exxon and other fossil fuel producers in funding climate denial movements has been really well documented for more than a decade,” says Muffett. “What’s changed in the past year and a half is that a growing body of evidence has come to light showing that at the same time as these companies were denying climate science publicly, their own best information was that it was real. In many cases they were adapting their own investments to account for climate reality.
“Once you understand that companies were on notice, that they had the opportunity to respond, and that they chose instead to operate differently, then you open up whole new realms of potential legal responsibility under a variety of legal theories.”
This matters to Exxon, but it also has a wider impact on corporate risks. Even Bank of England governor Mark Carney has warned of this.
“One of the rapid points of movement we’ve seen over the past year is accelerating awareness of these risks within the investment community,” says Muffett. “When investors face losses of this kind, they’re going to look to recoup them, including from the companies themselves.” And it could get personal; some lawyers say directors themselves could be liable for harm or even gross negligence manslaughter.
In this way, the repercussions of climate change litigation can also be felt far beyond an individual case itself. Even a losing claim can help drive companies or governments to update their laws or practices to protect themselves from future action.
The 2015 signing of the Paris Agreement was another important step. The final 12-page text itself is legally binding, and although it depends on individual country action plans, which are not, the deal will undoubtedly have important legal ramifications. 
Tim Crosland, a human rights and criminal lawyer who set up not-for-profit organisation Plan B earlier this year, is very interested in the fallout from Paris. Convinced that climate change was one of the world’s biggest problems and seeing its influence in many international crises, he involved himself in political negotiations, but soon became disillusioned with the process.
“I started to feel that part of the agenda with Paris was to safeguard against liability for developed countries,” says Crosland. “In other words, if we have an agreement that sets out nationally determined commitments as the basis for emissions reductions and everyone signs up to it, that can make it harder for a developing country or a victim country to sue.”
He is particularly concerned about the removal of a reference to historic liability in the agreement’s final draft, saying it makes hard-fought clauses on damage and loss meaningless.
However Crosland has since changed his view, and argues that the agreement should be read as providing a procedural framework for reporting but not a substantive framework for emission reductions. This, he says, means countries would still have to abide by their overriding duties under international law, for example not to cause harm to their neighbours. And this could be the subject of litigation.
“I came to the conclusion that if you’re serious about doing something about the climate change problem it needs to be through litigation, not the negotiation process.”
He is not the only one who thinks this. At a lecture on climate change justice in 2015, Supreme Court judge Lord Carnwath said it would ultimately be up to judges to sort through the legal implications of Paris.
The aim of Plan B was therefore to set up a network to support strategic legal action on climate change.
The idea was not to support one particular victim or stop a particular area being fracked, but to identify more universal principles that would help advance progress towards the long-term goal.
“One example would be establishing a principle of equitable burden-sharing, and Urgenda is a really good start on that – even if it’s just on the domestic level it’s really influential,” says Crosland.
Sharing the burden
Crosland’s “dream scenario” is a ruling by the International Court of Justice (ICJ) on what equitable burden-sharing means and a Nigerian farmer successfully bringing an action against Exxon for displacing him from Lake Chad that makes all carbon majors potentially liable for all loss and damage.
“That changes things really fast. What we’re trying to do is use the scale of damages, which is so massive, and get that factored into the market in some way, and the only way you do that is by making companies directly liable. And the ICJ judgment would be very powerful, because it would compensate for all the deficiencies of the UNFCCC process.”
“I think these are absolutely winnable cases – far more than has yet been tested,” he adds.
All these developments have caused lawyers and campaigners to change their approach. Both ClientEarth and Greenpeace, for example, are focusing their current efforts on preventing harm rather than reacting to it. Gillian Lobo, a lawyer at ClientEarth, works in a team that grew from a climate damage project into a wider examination of climate liability. “Clearly it is better to try to prevent the interference in the first place,” she says.
One key trend is that claimants are increasingly adopting more of a public law approach. Significant examples include the Urgenda case against the Dutch government, Leghari in Pakistan and the Our Children’s Trust’s constitutional claim in the US (see map). These were all brought by claimants against their respective governments, to compel them to take action.
The Our Children’s Trust cases, for example, are partly based on the ‘public trust doctrine’, an argument that natural resources, including the atmosphere, form part of a public trust that governments have a legal obligation to preserve. In the UK, some lawyers believe the Well-Being of Future Generations (Wales) Act 2015, which gave major responsibilities to all public bodies to satisfy the needs of people living in Wales without compromising those of future generations, could be the subject of similar cases in the future.
Crosland says there is also potentially a very strong human rights claim. “I’m used to making arguments on a human rights basis, and a lot of the time it’s very speculative. But when you’ve got a million reports from a million different agencies saying people are dying now from climate change, that they will keep dying unless we do something – that’s much easier for a court.”
The fossil fuel industry is also the subject of an increasing amount of legal action; important current cases are taking place in the Philippines and the US (see map, above).
Casper notes that the industry has successfully opposed litigation for climate damages in North America so far. “But it is becoming increasingly likely that companies could be sued by victims of climate change overseas, in countries with quite different legal systems. There, they might face lawsuits based on constitutional rights to a healthy environment, strict liability for environmental harm, or any number of other legal principles.”
Litigation against the harm of asbestos and smoking is commonly used as an analogy for what is happening now on climate change. “One of the most important parallels to tobacco is in the diversity of the plaintiffs,” says Muffett. “For the first couple of decades of tobacco litigation, the plaintiff always lost. And then it followed an arc where you had individual plaintiffs or their estates suing to recover from impacts to individuals. Then you had class actions. Then there was a real transformation with class actions from second-hand smokers who themselves weren’t complicit in the harms they were suffering. And then litigation expanded out to state attorneys who were seeking to recoup their state’s healthcare costs caused by smoking.”
Muffett says we are now seeing this “incredible diversity” of plaintiffs and legal strategies in the climate litigation space.
“The common factor behind many is they’re increasingly focusing on a smaller group of defendants – a group that sits in a very privileged position with respect of fossil fuel production and science and also an exposed position when you consider their legal and physical presence in countries across the world.”
The international dimension of this movement is important. Some courts are also open to reviewing cases in other jurisdictions, particularly from countries they perceive as politically or legally similar. Each country has its own legal system, and technically a case in one does not set a precedent in another. “But does it inspire others?” asks Casper. “Yes. There’s a very active discussion happening on the internet, on social media, where you’re seeing cross-pollination of ideas and theories. Climate change is a global problem with very local effects, but there can be similarities in the legal reasoning and argumentation used to bring cases.”
Crosland points out that concerns about confidentiality and intellectual property of legal arguments can prevent this kind of sharing. “Lawyers can be so focused on winning their individual cases that they can forget to be strategic,” he says ruefully.
But he believes a tactical approach is crucial. “This is the thing about climate change; we’re all affected and everybody’s a potential claimant. If you’re clever and strategic about this you can pick your jurisdiction, you can pick your claimants and fit them to the right principles.”
Lobo agrees that sharing information is important and says it is important to raise the profile of the many cases being brought. “That feeds into the dialogue and discussion about the role of the courts and what can be achieved. As seen in the Urgenda case, there has to be some sort of societal buy-in for judges to feel empowered to make some decisions. They will make unpopular decisions, but they have to understand the context in which they’re being asked to determine a case. The judges in Urgenda did, and recognised the need to take urgent action.”
Muffett agrees. “This is not a matter of a single campaign or movement. It is about growing groups of legal, civil society and government actors who are pursuing these cases for reasons that are often entirely their own. That is part of what makes me optimistic.”
One piece of news that casts a shadow over the general enthusiasm is Donald Trump. Speaking to Muffett on the morning after the US election, he admits the results could be problematic. “We have already seen that in the US efforts to investigate Exxon and other oil companies and hold them accountable are being met with really intense resistance, including investigations driven by the [House Science, Space and Technology Committee] seeking to intimidate and suppress those that would seek to investigate Exxon itself (see map).
“It’s a reality we need to grapple with. The legal routes forward will become more treacherous but the path is still there – it’s just going to take more courage for those pursuing it.”