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Climate Change Litigation

By Valentina Menendez Ron


Climate change litigation is growing exponentially, with over 1,500 climate-related lawsuits worldwide. This has caused some debate about the role adjudication should have in the development of this area of law. The following essay will analyse different aspects of this phenomenon: introduce climate change litigation, discuss which legal obstacle can be overcome thanks to attribution science and, finally, examine the role of climate change litigation as a climate change regulatory tool. All with the help of the relevant international law and case law.


The goal of climate change litigation is to use the law to create outcomes that could help either mitigate or reduce climate change itself. That is beacause, on one hand, a positive outcome of a case could put pressure on the legislative branch to be more ambitious in fighting climate change. On the other hand, in countries where there is not that much climate law, litigation can also help fill in the gaps caused by such inaction.

Type of cases

Climate law cases can be heard by both national and international courts and tribunals. Disputes can be concerned with different aspects of climate laws and policies, such as mitigation and adaptation measures. At a national level, they can be public law litigation such as judicial review or claims of administrative responsibility, or private law litigation on approaches to address loss and damage. And more importantly, they take place in very diverse legal systems and traditions.

Legal Basis

But on what grounds can a party bring about such actions in front of a court? Recent years have brought about a considerable expansion of climate change litigation, which has allowed lawyers and judges alike to use a plethora of legal theories based on different sources of law. This would include both international law and national law (such as common or statutory law, constitutional law, national policy, etc).

International law offers protection to people against those who contribute to climate change on the basis that those individuals endangered their human rights. It has long been established that the right to a clean environment is a fundamental human right and it has been codified in, inter alia, international human rights treaties, soft law instruments and national constitutions. For instead, in Greenpeace Southeast Asia et al, Gbemre v. Shell Petroleum Development Company of Nigeria Ltd the court held that the practice of gas flaring is unconstitutional under the Constitution of Federal Republic of Nigeria and the African Charter on Human and Peoples Rights as it violates the guaranteed fundamental rights of life and dignity of human persons.

In addition, and looking into the future, it is likely that refugee law will become more relevant if we take into account that climate change will start to displace millions of people from their homes.

Having said that, it is relevant to point out that so far the majority of litigation related to climate change has taken place in national courts, so it is importnat to pay attention to the legal framework of the state in question. Some countries have included climate change obligations in statutes or national policies, as is the case of the Climate Change Act 2008 in the United Kingdom.

In other cases, different states have guarantee the specific right to a clean or healthy environment to their citizens. In Sentencia C-035/16 de febrero 8, 2016, Colombia’s Constitutional Court struck down provisions of Law No. 1450 of 2011 and of Law No. 1753 of 2015 that threatened páramos (high-altitude ecosystems), which provide 70% of Colombia’s water and also sequester carbon dioxide. However, very few countries have seen fit to address climate change at a constitutional level and, sadly, international agreements like the Paris Agreement cannot be a substitute for such provisions.


However, climate change litigation does not come without its challenges, which vary from jurisdiction to jurisdiction.

One of this is the question of justiciability. Firstly, there is the issue of standing, which may pose a barrier to climate change litigation. These may be that it is difficult for an individual to establish their right to sue a party that has caused them harm. In Dual Gas Pty Ltd. v. Environment Protection Authority, an australian tribunal found that three of the four plaintiffs had standing to sue because they had interests that would be affected by the new power station. Thus, they demonstrated a “special interest” in the alleged harms and this is protected under the Environmental Protection Act. This is heavily linked with the issue of causation, which will be discussed more below.

Secondly, the issue of standing reflects on a second challenge: the separation of powers, which will be discussed more further down.


In the case that a claim passes through the procedural hurdles of justiciability, it would face the more strict causation standards. That is, to determine a plaintiff’s entitlement to remedies, they must first successfully attribute losses to the defendants’ actions. Current case law indicates that there are real challenges to satisfying causation tests in climate-related litigation, even in jurisdictions where the more flexible causation tests are applied.

Obstacles it helps overcome: Causation

And here is where probabilistic event attribution can be helpful. Attribution science investigates the extent to which climate change caused by humans “has altered the probability or intensity of a particular weather event or class of weather events”. For instead, nowadays scientists have found a way of quantifying the contribution of GHG emissions to extreme events (including storms, droughts, heatwaves or floods), long-term trends in glacier lengths or sea levels and persistent changes (in temperatures or precipitation). Therefore, this current scientific methodology could fill the evidentiary gaps identified by courts in the field of climate change attribution.

One of the many problems related to GHG emissions is that they come from multiple sources as a consequence climate change oftentimes results from the cumulative emissions of multiple parties, which could make it hard to pinpoint a loss to a single emitter. Attribution science could help overcome this obstacle.

On one hand, existing as well as new studies could be used as evidence to directly quantify individual defendants’ contributions to plaintiffs’ losses. On the other hand, they may also strengthen legal claims by providing that a defendant’s conduct has made a plaintiff worse off. The latter could come in handy in a jurisdiction where causation tests are met by showing how the magnitude of harm was altered by an individual defendant’s conduct. For example, the “but-for” test is used in many common law countries such as the United Kingdom: “but for the defender’s negligence, the pursuer’s loss would have occurred?”.

Attribution science has made improvements in determining the foreseeability of climate change impacts resulting from future emissions patterns in specific locations. Thus, there is a possibility of identifying it is increasing risks and what impacts its going to have on people.

From a legal point of view, these improvements are key since the foreseeability of damage is an important requirement to establish a duty of care in many legal systems. In Scotland, for example, establishing a case of negligence requires three things: the defendant owed the plaintiff a duty of care, there must be a breach of duty of said duty and the breach must cause. However, that loss or injury must be reasonably foreseeable.

Possible Problems with Attribution Science

Therefore, attribution science could do a lot of good for establishing causation in climate change litigation. Nevertheless, some details could make people undermine its effectiveness.

We have to acknowledge that attribution studies are typically probabilistic. This is because scientists when analyzing the influence of anthropogenic factors when comparing the “real world” to a world that has not been impacted by human actions (greenhouse gases, for instead), refuse to say that an event would “never” have occurred in that “other” world. There is always the possibility that an event could occur, even without human influence.

However, the fact that the results are merely probabilistic does not diminish the utility of attribution science for the law. Legal frameworks have already been established for holding defendants responsible for changes in an event’s probability even if they make only a partial contribution to this change. In Heneghan v Manchester Dry Docks Ltd and Ors, a UK court found that asbestos exposure was the cause of the claimant's lung cancer on the balance of probabilities, as epidemiological evidence established that the risk of the cancer being caused by asbestos was greater than 2:1 ( the doubling the risk test). Thus, it could be argued that attribution science is theoretically capable of establishing a sufficient causal link in climate change litigation. But we should not forget that this may vary depending on the jurisdiction and the test they use for this situation.

Nevertheless, attribution science is improving our ability to detect human influence on extreme weather events. This could lead to more climate change litigation with better outcomes for the parties that bring it to court since the issue with causation would be reduced.

Application in practice

And although there is a clear relevance of using attribution science as evidence, there is limited precedent of case law to base findings of causation on such evidence, partly due to its relative novelty. But in Sacchi et al. v. Argentina et al. Communication to the Committee on the Rights of the Child has use it. In this case, sixteen children from Argentina, Brazil, France, Germany and Turkey filed a petition alleging said countries violated their rights under the United Nations Convention on the Rights of the Child (hereinafter the Convention) since they did not make satisfactory cuts to greenhouse gases and fail to use available tools to encourage the world’s biggest emitters to curb carbon pollution.

The petition states that respondents have four obligations under the Convention, one of them being the prevention of foreseeable domestic and foreing human rights violations resulting from climate change. Brazil, France and Germany fought back against the petition and argued that, inter alia, it was not admissible on the grounds that there was no causal link between the greenhouse gas emissions originating in their territory and the harm caused to the children.

Nevertheless, the petitioners presented scientific studies and were able to prove that the claims are “manifestly well-founded because they are suffering direct and personal harms now and will continue to in the foreseeable future”. In other words, there is a causal link. Among the documents presented were multiple studies from the Intergovernmental Panel on Climate Change, which is “the world’s foremost authority on climate science”, as well as various statistical models.

The use of attribution science was acknowledged by the Committee and they also use it when given their decision. They found that, based on the scientific evidence presented, the children were indeed victims of foreseeable threats to their rights to life, health, and culture. But, since the petitioners did not exhaust local remedies, it was held that the complaint was inadmissible for a failure to exhaust local remedies.

Ultimately, Sacchi et al. is proof that attribution science can help overcome one of the main problems related to climate change litigation: the establishment of causation. And if it were not for the fact that the petitioner did not go to their local courts first, this could have been a successful case.


Having discussed what is climate law litigation and how attribution science can help overcome certain obstacles that this type of case might find, it is important to analyse the role said litigation can have as a regulatory tool.

It is important to understand that climate law adjudication arose due to the frustration over how slow the pace of the negotiation has been since the 1990s. Due to the absence of enforceable commitments from the government, it was considered at the time that litigation may play an important role in reducing greenhouse gas emissions. But, much of this litigation has been unsuccessful. This has changed recently and there has been several significant successes on climate law adjudication in the past several years, including in the Urgenda case.

However, even though the case law that has emerged over the years is important, most of the action in international environmental law generally still takes place in the negotiating rather than the adjudicatory space. Taking this into account, could there still be a role for litigation, nationally or internationally? Should that role be that of a regulatory tool?


The law that focuses on climate change at an international level is limited. Three main legal instruments have been the culmination of negotiations: the UNFCCC, the Kyoto Protocol and, most recently, the Paris Agreement. But, even though they have offered a lot to this field, many of the key provisions, including the way the states determined their contributions to reducing emissions are not legally binding.

The UN regime has generally adopted a “managerial rather than an enforcement approach to compliance”. The United Nations Framework Convention on Climate Change (hereinafter UNFCCC) proposes a “communication of information,” and the establishment of a “multilateral consultative process” rather than a “compliance procedure”. This way the UN preserve the wish of the states to respect their sovereignty in terms of how they deal with climate change. And this could and has created uncertainty for the future of the UN climate. A good example of this is the withdrawal of the United States from the Paris Agreement during President Trump's mandate.

In these circumstances, a decision by the International Court of Justice, or any other international court that has jurisdiction, could potentially play a positive role. Either by helping move the negotiations along or by helping to interpret and regulate the existing law. Moreover, in the negotiations, little is ever settled definitively. Litigation, in contrast, would not be subject to endless renegotiation since it exists outside the will of the parties.

At a national level, climate law litigation has also helped regulate climate law. They do so by either applying international law directly (in jurisdictions where this is allowed) or by relying on domestic law. And by doing this, some courts have managed to compel national authorities to adopt a course of conduct consistent with their international obligations. And even if the case has a bad outcome, it still has the opportunity to bring awareness about the issue at hand and the harm it causes. A good example of this is the case of Kivalina v. ExxonMobil Corp.


But the use of climate change litigation as a regulatory tool also has its disadvantages. The international climate negotiations had finally shown significant progress with the early entry into force of the Paris Agreement. Given this momentum, it could be argued that international climate litigation might have a better chance to cause trouble than to do good, by distracting from and even interfering with the negotiations.

From a political standpoint, states generally have little inclination to engage in proceedings against one another to address global environmental problems, as such proceedings would involve diplomatic costs not justified by the achievement of any specific national interest. Political obstacles are greater in circumstances such as climate change where the most affected States are often among the weakest diplomatic powers.

Furthermore, litigation represents a radical departure from the approach the United Nations climate change regime has taken from its inception. Under the rule of negotiations, agreements serve not as a cap, but as “punctuation marks” in an ongoing process of debate among states. This also goes in line with the concern of states to protect their sovereignty in climate change negotiations. Not respecting this was arguably one of the main problems with the Kyoto Protocol, which proposed an internationally-defined emission targets. It was later on fixed in the Paris Agreement by allowing the definition of their state emission reduction policies through “nationally determined contributions” (NDCs). This could show that judicial decisions would be easily accepted by some countries as few states are willing to accept externally-defined limits on their emissions and, thus, a step back could take place in the negotiations.

For this reason, it could be argued that negotiations are more likely to be effective, as a practical matter, in influencing state behaviour and bending the emissions curve. States, when entering an international treaty, commit to the norms to which they have agreed, more than those imposed on them from outside litigation. And if they fail to do so, then there are the reputational costs of breaking a negotiated agreement that may be higher than the costs of non-compliance with a judicial decision. States could simply ignore adverse decisions with few immediate consequences.

But these arguments about the role of international courts in addressing climate change do not apply to national courts, because the relevant comparator is legislation and not negotiation. For instead, there is the issue of separation of powers. This doctrine establishes that one branch of government cannot use the authority given to it by the law to intrude on the authority of another branch. Thus, courts must limit themselves to exercising only judicial power. Many see climate change as highly political, therefore we must ask ourselves if the court is the right place to discuss this issue. In Urgenda Foundation v. State of the Netherlands, the Hague District Court rejected the government’s argument that the court order they issued requiring the State to limit GHG emissions constituted a violation of trias politica. The court went ahead and argued that Urgenda’s claim concerns the legal protection of rights and they are obliged by Dutch law to assess the actions of political bodies when the rights of citizens are at stake. Even if the decision of the case has political outcomes. Thus, it could be argued that as long as the question presented to the court relates to the rights of its citizens, then they have the right to hear and decide in it. But, a lot depends on how the question is presented and we also have to take into account that every jurisdiction is different.

Overall, the use of climate change litigation as a regulatory tool has its advantages and disadvantages. It could be argued that it should not be pursued if it is going to create tension between the states and divert attention away from the negotiations. Thus, international courts should probably focus more on issues that are more abstract in nature and make a positive difference.


Ultimately, climate law litigation emerged as a reaction to the incapacity of the countries around the world to reach an agreement through negotiation. And now that it is here, it is likely that it is going to stay. The reluctance shown by the states could indicate that the role this type of adjudication is going to take is more of a supporting role, leaving the main one for international negotiations and national legislation. And whenever national governments and parliaments fail to act, the courts should be there as a last resort for meaningful steps forward. And thanks to the help of attribution science, a new wave of cases could be more successful than the last.



  • Cases

  • Bolitho v. City and Hackney Health Authority [1996] 4 All ER 771

  • Caparo Industries PLC v Dickman [1990] UKHL 2

  • Dual Gas Pty. Ltd. and Others v Environment Protection Authority [2012] VCAT 308

  • Greenpeace Southeast Asia et al, Gbemre v. Shell Petroleum Development Company of Nigeria Ltd (2005) AHRLR 151 (NgHC 2005)

  • Heneghan v Manchester Dry Docks Ltd and Ors [2014] EWHC 4190 (QB)

  • Kivalina v. ExxonMobil Corp., No. 4: 08-cv-01138

  • Sentencia C-035/16 de febrero 8, 2016

  • Sacchi et al. v. Argentina et al. Communication to the Committee on the Rights of the Child (23 September 2019)

  • Urgenda Foundation v State of the Netherlands [2015] HAZA C/09/00456689

  • International Treaties

  • United Nations Framework Convention on Climate Change (adopted 2 May 1992, entered into force 21 March 1994) 1771 UNTS 107


  • Books

  • Mayer B, The International Law On Climate Change (Cambridge University Press 2018)

  • Thomson J, Delictual Liability (5th edn, Bloomsbury Professional 2014)

  • United Nations Documents

  • United Nations Environmental Programme, The Status of Climate Change Litigation – A Global Review (May 2017) pp. 6 and 27-40.

  • Journal Articles

  • Bodansky D, ‘The role of the International Court of Justice in addressing climate change: some preliminary reflections’ ( 2017 ) 49 Arizona State Law Journal 689.

  • Bodansky D, ‘The Legal Character of the Paris Agreement’ (2016) 25 REV. EUR. COMMUNITY & INT’L ENVTL. L. 142

  • Marjanac S, Patton L, and Thornton J, ‘Acts Of God, Human Influence And Litigation’ (2017) 10 Nature Geoscience

  • Okonkwo T, ‘Protecting the Environment and People from Climate Change through Climate Change Litigation’ (2017) 10 J Pol & L 66

  • Rosen A, ‘The Wrong Solution At The Right Time: The Failure Of The Kyoto Protocol On Climate Change’ (2015) 43 Politics & Policy

  • Online journals

  • Stuart-Smith R, et al, ‘Filling The Evidentiary Gap In Climate Litigation’ (2021) 11 Nature Climate Change <> accessed 12 January 2022

  • Websites

  • ‘Sacchi, Et Al. V. Argentina, Et Al. - Climate Change Litigation’ (Climate Change Litigation, 2022) <> accessed 15 January 2022

  • Newspaper Articles

  • Holden E, ‘Trump Begins Year-Long Process To Formally Exit Paris Climate Agreement’ The Guardian (Washington, 5 Nov 2010) <> accessed 16 January 2022

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