Legal implications of the climate-health crisis: A case study analysis of the role of public health in climate litigation

RESEARCH ARTICLE Legal implications of the climate-health crisis: A case study analysis of the role of public health in climate litigation Narayan Toolan1,2☯*, Hannah MarcusID2,3☯*, Elizabeth G. Hanna4,5‡, Chadia WannousID2,6‡ 1 UCLA School of Law, Los Angeles, California, United States of America, 2 World Federation of Public Health Associations–Environmental Health Working Group, 3 School of Public Health, University of Alberta, Edmonton, Alberta, Canada, 4 Australian National University, Fenner School for Environment and Society, Canberra, Australia, 5 WG Chair, World Federation of Public Health Associations–Environmental Health Working Group, 6 Towards A Safer World Network and Future Earth Health-Knowledge Action Network, Stockholm, Sweden ☯ These authors contributed equally to this work. ‡ EGH and CW also contributed equally to this work. * narayantoolan@gmail.com (NT); hannahmarcus6@hotmail.com (HM) Abstract Background Strong scientific evidence affirms that climate change is now a public health emergency. Increasingly, climate litigation brought against governments and corporations utilizes inter- national human rights, environmental and climate laws and policies to seek accountability for climate-destructive and health-harming actions. The health impacts of climate change make litigation an important means of pursuing justice and strategically challenging legal systems. Yet there is scant documentation in the literature of the role that public health has played in climate litigation and the legal weight public health narratives are given in such

contexts. Therefore, we assessed to what extent courts of law have used public health harm in legal adjudication and sought to provide practical recommendations to address barriers to positioning legal arguments in public health-centric frames. Methods We reviewed legal databases to identify all publicly reported, documented, cases of climate litigation filed in any country or jurisdiction between 1990 and September 2020. For the 1641 cases identified, we quantified the frequency of cases where health concerns were explicitly or implicitly raised. Findings Case numbers are trending upwards, notably in high income countries. Resolution remains pending in over half of cases as the majority were initiated in the past three years. Cases were primarily based in climate and human rights law and brought by a wide range of groups and individuals predominantly against governments. About half of the decided cases found PLOS ONE PLOS ONE | https://doi.org/10.1371/journal.pone.0268633 June 15, 2022 1 / 31 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS Citation: Toolan N, Marcus H, Hanna EG, Wannous C (2022) Legal implications of the climate-health crisis: A case study analysis of the role of public health in climate litigation. PLoS ONE 17(6): e0268633. https://doi.org/10.1371/journal. pone.0268633 Editor: La´szlo´ Vasa, Szechenyi Istvan University: Szechenyi Istvan Egyetem, HUNGARY Received: April 19, 2021 Accepted: May 4, 2022 Published: June 15, 2022 Copyright: © 2022 Toolan et al. This is an open access article distributed under the terms of the

Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All data used to develop this report is publicly available on the respective case law databases of the Grantham Research Institute on Climate Change and the Environment (https://www.lse.ac.uk/ granthaminstitute/), and the Sabin Center for Climate Change law (https://climate.law.columbia. edu/). Additionally, the minimal dataset can be found in the paper and Supporting Information files.

in favour for the plaintiffs. Based on this, we selected the 65 cases that were directly linked to public health. We found economic forces and pricing of health risks play a key role, as courts are challenged by litigants to adjudicate on the responsibility for health impacts. Conclusions While courts of law are receptive to public health science, significant legal reform is needed to enhance leveraging of public health evidence in legal judgements of climate litigation cases. The integration of a public health mandate into a new eco-centric legal paradigm will optimize its potential to promote human well-being—the core objective underpinning both international law, human rights, and public health. Existing legal doctrines and practices can be enhanced to increase the weight of public health arguments in climate legal action and consequently ensure legal rulings in climate litigation prioritize, protect and promote public health. Introduction Since its inception, environmental law has been relied upon as a means of preventing harm to the environment, thus enabling healthy human relationships with the environment. Escalating Climate Change impacts across the world is increasing potential for litigation to be brought against corporations, governments, and other parties by individuals and communities on the basis of current or future harm to their health and wellbeing. This risk of legal liability is a key factor in shaping climate-compliant economies whereby actors seek to protect assets, minimize

risk and seek opportunities that are within the boundaries of legal regulatory frameworks. As the field of climate litigation has evolved, so have the legal strategies used to prosecute claims of wrongdoing. Only in the last few years have cases emerged from all areas of law including corporate law, financial law, and human rights, as strategic tools in the pursuit of liti- gation against climate-disruptive actions by corporations, governments, and other parties. The rising trends in litigation have been monitored and recorded by various scholars [1, 2]. With growing evidence of the health impacts resulting from climate change, it is unsurprising that public health concerns now feature more strongly in litigation. Yet there is scant documenta- tion in the literature characterizing the role that public health arguments have played in cli- mate litigation and the legal weight given to public health narratives. Despite solid scientific evidence and the efforts of many, global greenhouse gas emissions are not reducing [3]. Similarly, despite environmental protection laws, environmental damage is demonstrably escalating as ecosystems decay is generating a sixth mass extinction [4]. The human species cannot flourish amid sick ecosystems. Healthy environments and a stable cli- mate are necessary for human survival. Their disruption directly harms human health. In recognizing that climate change is unfolding as a health emergency that disproportion- ately impacts the most vulnerable, health professionals are urging for accelerating efforts to

decarbonize [5]. Accordingly, the public health community has increasingly issued calls for a “public health focussed response” across prevention, mitigation, adaptation, and preparedness [6]. Central to this approach is the need to ensure that viable legal avenues for deterring, halt- ing, and seeking justice for climate-disruptive, health-threatening actions exist. To support this objective, this review provides a comprehensive analysis of the role of public health in PLOS ONE Public health as a legal tool in climate litigation PLOS ONE | https://doi.org/10.1371/journal.pone.0268633 June 15, 2022 2 / 31 Funding: The authors received no specific or any funding for this work. Competing interests: The authors have declared that no competing interests exist. Abbreviations: IPCC, International Panel on Climate Change; CLL, Climate Change Litigation.

climate litigation and provides practical recommendations to address barriers to positioning legal arguments in public health-centric frames. Climate Litigation reveals the ways in which the threats of litigation can shape the transition to an economy which is not based on environmentally-devastating anthropogenic activities. Therefore, there is an urgent need for individuals, groups, stakeholders, and consumers to bring litigation that is correlated to a public health concern. Although litigation is often a lengthy, stressful and costly process, it may force governments and corporations to prioritize planetary and human health over profit. Background Climate change and human health Since its identification as a growing environmental threat, climate change has generated con- cern from a variety of disciplinary perspectives. Only relatively recently has the public health perspective gained traction within the broader climate policy dialogue. There is now robust data to substantiate the claim that climate change significantly and neg- atively impacts human health both directly and indirectly through a series of complex, inter- acting social and environmental determinants. This climate-health nexus featured strongly in the IPCC’s Fifth Assessment Report (AR5) [7] and was further expanded in the Working Group II contribution to AR6, Climate Change 2022: Impacts, Adaptation and Vulnerability [8]. Climate-driven health threats have taken the form of rising food [9, 10] and water [11, 12] insecurity, deteriorating air quality [13, 14], new infectious disease outbreaks [15–17], and

fatal and disease-inflicting floods [18], droughts [19, 20], coastal storms [21, 22], wildfires [23, 24], heat waves [25, 26], as well as ecological grief and disaster-induced trauma which drive mental health illnesses worldwide [27, 28]. Intensifying climate-related disasters and food and water shortages also have broader, indirect consequences on human health, as mediated by their effects on patterns of conflict, forced displacement, and migration [29–31]. This ongoing “climate-health crisis” is expected to contribute further to rising global mor- bidity and mortality and social and economic suffering in the years to come [32]. Yet as stated in the Lancet Commission on the Legal Determinants of Health, “While law can be a powerful tool for advancing global health, it remains substantially underutilised and poorly understood. Working in partnership, public health lawyers and health professionals can become champi- ons for evidence-based laws to ensure the public’s health and safety” [33]. Law is a powerful tool to advance global health because climate change adversely affects the physical health and mental health of people in all countries [34]. Present development challenges causing high vul- nerability are influenced by historical and ongoing patterns of inequity such as colonialism, especially for many indigenous peoples and local communities [34]. Yet, according to the World Economic Forum “groups of stakeholders (the private sector, corporate and financial organizations) have taken part in a system that funds the destruction of nature” [35]. This is

enabled by a rule of law, which more often gives primacy to corporate rights over the health of nature. Using scientific evidence, namely climate science and public health, law can advance health, human rights, and the rights of nature. Climate law, policies and economic incentives Climate laws and policies are concerned with ‘mitigating, regulating or adapting’ industrial activity which causes climate change. The United Nations Framework Convention on Climate Change (UNFCCC) was signed by 154 states in 1992 acknowledging “that the global nature of climate change calls for the widest possible cooperation by all countries and their participation PLOS ONE Public health as a legal tool in climate litigation PLOS ONE | https://doi.org/10.1371/journal.pone.0268633 June 15, 2022 3 / 31

in an effective and appropriate response” [36]. Both the Paris Agreement [37] adopted by the Conference of the Parties (COP21) and the “UN Sustainable Development Goals (SDGs)” have guided development in this field. Although, health is not always specifically articulated in national laws and policies that address economic regulations on energy, electric utilities, con- struction, agriculture and industry, it is commonly implicit that the objective of these policies is human and planetary ecosystem survival. The evidential failure of implied protection of planetary health, stability of the climate and human health through existing laws provides a powerful argument that such protections must be made explicit and legally binding. For most nations the legal basis exists as in 2015, 193 nations endorsed the SDGs including SDG 3, which aims to “ensure healthy lives and to promote well-being for all ages” [38] and the Paris Agreement, endorsed by 196 countries, emphasizes the “right to health”. Whereas the SDGs are not legally binding, the Paris Agreement is. [39]. Yet with few legal teeth, it does not impose penalties, such as fees or embargos, for parties that violate its terms, and there is no international court or governing body ready to enforce compliance. Experts argue that in real- ity, the Paris Agreement is not legally binding [40]. The emerging field of climate law is inter-disciplinary and extends to often unsatisfactorily defined concepts such as a ‘carbon net zero economy’ and ‘sustainable finance’. Since 1992, the

United Nations Environment Program (UNEP) Finance Initiative (FI) has partnered with the global financial services sector including banks, insurers, and investors in a commitment that “we . . . recognize that economic development needs to be compatible with human welfare and a healthy environment” [41]. Yet whilst older environmental regulations have provided legal avenues to petition for public health justice, they have been hindered by the economic ideology that profit trumps health, ecology, and ecosystems [42]. Public health, the environment, and law Environmental health-related legal frameworks. A relevant legal framework with impli- cations for environmental health promotion is the International Environmental Law (IEL). IEL is concerned with the attempt to control pollution and the depletion of natural resources within a framework of sustainable development [43]. The resource management and pollution control components which comprise this framework make it inherently linked to public health objectives, despite there being no explicit mention of human health in many IEL statutes [44]. In October 2021, the United Nations, Human Rights Council (HRC), recognized that having a clean, healthy, and sustainable environment is a human right, however this is not a legally binding obligation [45]. Relevant IEL statutes include “The Declaration of the United Nations Conference on the Human Environment” (the 1972 Stockholm Declaration) [46] and “The Rio Declaration on Environment and Development” (the Rio Earth Summit) [47]. Inherent in both statutes is the

legal mandate to prevent, wherever possible, the degradation or depletion of environmental resources needed to sustain planetary life. In both declarations, one can observe an anthropo- centric focus on human health and the prevention of environmentally destructive actions which would be detrimental to it, namely those which interfere with life sustaining ecosystem services, as defined by the Millennium Ecosystem Assessment [48]. International Human Rights Law (IHRL), like IEL, features an implicit focus on human health and well-being, albeit through the imposition of protective policies against abusive acts which could threaten any one of its many sub-domains. There are notable areas where IHRL and IEL intersect to promote a policy environment conducive to human health. For example, climate-friendly policies are increasingly being linked to our moral duty to uphold Article 3 of the Universal Declaration of Human Rights [49] which states that “Everyone has the right to PLOS ONE Public health as a legal tool in climate litigation PLOS ONE | https://doi.org/10.1371/journal.pone.0268633 June 15, 2022 4 / 31

life, liberty and security of person”—rights which climate destructive actions explicitly threaten. Yet “environmental law continues to struggle with the complaint that it re-articulates some of the patterns of colonial exploitation in environmental terms”, most notably by treating nature’s resources as mere commodities and by failing to provide an enabling framework for indigenous populations to regain rightful stewardship over their lands [50]. Hence, reconciling environmental and human rights law remains an ongoing process, one which will arguably be central to creating a health-friendly legislative environment in the years to come. On a national level, Environmental Law consists of statutes, regulations, applied common law, and in some countries, constitutional provisions. Currently, 155 countries have binding legal obligations to respect, protect and fulfill the right to a healthy environment [51]. Environ- mental rights consist of procedural rights (e.g. access to information, access to justice, right to participate in environmental decision making) and substantive rights (i.e. civil and political, economic and social, cultural, and collective rights) which implicate legal requisites to prevent- ing environmental degradation [51]. Mapping the landscape within which environmental health features in international law also requires an understanding of International Health Regulations (IHR) which, in principle, embody a legal commitment of governments to respond to environmental health threats. The

IHR are legally-binding for all 194 WHO member states and include requirements to report public health events with potential to cross borders and to maintain core capacities for pre- paredness, surveillance and response [52]. Consequentially, it can be said that obligations under the IHR imply a commitment to sound governance in response to environmental health emergencies which, by nature, have high potential to transcend international borders. Climate change litigation Litigation is defined as “the act, process, or practice of settling a dispute in court of law” [53]. What is often disputed in climate litigation, is whether governments or market actors are ‘miti- gating, regulating or adapting’ industrial activity which causes climate change. According to the IPCC [54], system change is required across all industrial sectors to substantially reduce greenhouse gas (GHG) emissions. Litigants and lawyers use such statements to support liti- gation and in recent years, individuals and communities have aligned their causes of social, human and economic justice with environmental and climate justice. Indeed, the Paris Agree- ment notes “the importance for some of the concept of climate justice, when taking action . . .” [37]. Legal Liability is defined as the “responsibility that someone has for their actions, for example the responsibility to pay another person for harm or damage that is the result of these actions” [55]. Climate laws and policies create new legal liability for market actors, but there is increasing

by allowing for evidence on proportional responsibility. The UNEP 2020 global status review on climate litigation suggested that climate attribution is being given more weight in the con- sideration of cases and determination of legally enforceable outcomes [58]. There are several types of detection and attribution studies focusing on: trends or long- term changes in climate variables; changes in extremes; weather or climate events; climate- related impacts; and the estimation of climate sensitivity using observational constraints. Detection and attribution studies can be done at various scales ranging from regional to global [59]. CCL includes both (a) cases where the claim is based on an established law, for which com- pliance/enforcement is sought, and (b) cases where there is no established law, but claimants assert that there ought to be (e.g. through expanding the scope of existing constitutional man- dates, human rights statues, common law principals, etc). CCL has often been pursued through the international legal pathways of multilateral institutions and the United Nations system, drawing upon such doctrines as The Convention on the Rights of the Child, OECD Guidelines for Multinational Organizations, and the International Covenant on Civil and Political Rights, amongst others. In the European Union (EU), litigation has often been orchestrated via reference to the Charter of the Fundamental Rights of the EU in addition to other relevant national/ interna- tional laws [60]. In the United States, CCL has been brought at both federal and state levels

[47]. Most CCL has been against governments, but cases have been increasingly against corpo- rate entities in relation to a widening array of financial, company, and corporate planning laws [61]. With growing requirements for corporate adherence to Environmental and Social Gover- nance Standards (ESG’s), litigation against corporations is likely to increase in frequency in future. Interestingly, eco-centric law is becoming a reimagination of the anthropocentric founda- tions of the international legal system. Eco-centric concepts are transforming human-centered legal systems, that historically undervalue non-human life. This is based on newly articulated eco-centric ideas that “to treat nature as just one of several competing (economic) interests results in a tendency to trump more qualitative public interest notions, such as ecosystem pro- tection, intergenerational and intragenerational equity and even cultural values” [62]. This represents a profound departure from an anthropocentric framing of the environment as a mere resource-giving vehicle for human exploitation towards viewing the environment in Kantian terms, as “an end in itself”, as a legal entity with rights of protection. Eco-centric concepts now extend to “wild property law”, ascribing personhood to “Eco- entities” in law, and laws of “Ecocide”. The French government is the first country to pass a law of Ecocide (2020) [63]. Despite some commentators saying this is a diluted form of the citi- zens’ convention recommendation, this is another indicator of the increasingly eco-centric ori-

entation of recent legal developments. As legal developments are stimulated by this normative shift towards eco-centricity, a growing focus for public health stakeholders will pertain to the incorporation of a public health mandate into this new eco-centric legal paradigm. Will eco- centric laws be grounded in the One Health model [64] championed by environmental health practitioners and others? Will they respond to our need to reconcile goals of societal develop- ment, public health, and ecological preservation? It is these questions at the intersection of law and public health which will be important to address in future interdisciplinary collaborations. Eco-centric laws have been passed in countries including: Ecuador in 2008 [65], Bolivia in 2010 and 2012 [66] (Law of the Rights of Mother Earth and Law of Mother Earth) and Panama in 2022. Panama grants nature the “right to exist, persist, and regenerate its life cycles”, defined as a “unique, indivisible and self-regulating community of living beings, elements and eco-sys- tems interrelated to each other that sustains, contains and reproduces all beings” [67]. Other PLOS ONE Public health as a legal tool in climate litigation PLOS ONE | https://doi.org/10.1371/journal.pone.0268633 June 15, 2022 6 / 31

eco-centric laws have been codified in Colombia, Mexico, Uganda, and are included in Chile’s proposed constitution. In the United States, rights of nature have been shaped at the local level in more than 30 instances, including in the states of Pennsylvania, Florida, Minnesota and Colorado. Giving rights to nature is a way to fulfill the human right to a clean, healthy and sustainable environment, as they are inter-dependent. Ultimately, both public health promotion and legal reform have common aims of creating a policy landscape conducive to human well-being. The integration of a public health mandate into a new eco-centric legal paradigm will optimize its potential to promote human well-being—the core objective underpinning both international law and public health. By knowing to what degree public health has featured in the empirical arguments used to justify climate legal action to date, we can better understand how well exist- ing eco-centric and other environmental health laws lend themselves to public health promo- tion. Should gaps be identified, we can begin to postulate how existing legal doctrines and practices can be enhanced to increase the credibility of public health arguments in climate legal action and by consequence, ensure legal rulings on climate litigation have positive impli- cations for public health. Objectives The Grantham Research Institute on Climate Change and the Environment and Centre for Climate Change Economics and Policy examined in 2021 global trends in climate change liti-

gation [68]. Our objective is to extend this work, by examining the extent, characteristics and success of cases based on protecting human health, either directly or indirectly by safeguarding environmental determinants of health. Given a) the rising recognition of the human health threats posed by climate change and environmental devastation and b) the pre-existing and growing legal focus on protecting the environment (in both anthropocentric and eco-centric frames), on preventing infringement on the human right to health, and on regulating industry to protect public health, we set out to answer the following research questions: 1. In what ways has climate litigation evolved as a legal tool for climate action, and contributed to liability, particularly under the agenda of protecting the environment, safeguarding human rights, and promoting public health? 2. How receptive have courts been to legal cases grounded on public health? 3. How have references to public health contributed to legal decision-making in climate litigation? Method We identified databases, with access to litigation documents, and judgements, of climate liti- gation, including translations from non-English languages. A review of climate science, legal databases was conducted on all such publicly reported, documented, English language (and translated) cases of climate litigation filed in any country or jurisdiction between 1990 and September 2020, to identify cases which relied upon public health science and can be catego- rized as public health climate litigation.

The following search terms were entered into available legal case databases: “climate change”, “climate change and public health”, “human rights and climate change”, “govern- ments and climate change”, “corporations and climate change”. PLOS ONE Public health as a legal tool in climate litigation PLOS ONE | https://doi.org/10.1371/journal.pone.0268633 June 15, 2022 7 / 31

We found litigation which was reported using the term climate change, or where it was implied by the subject via reference to relevant social issues, biodiversity loss, environmental degradation, carbon emissions, economic/land/property loss, linked legal regulation, or linked corporate governance. Cases were also found where climate change was peripheral to the argu- ment such as where general environmental destruction was the primary concern, yet climate disruption was alluded to as a secondary consequence. We extracted consistent, basic, pre-defined data from the cases documents on plaintiff, defendant, legal precedent, decision, core argument, and court, to assess cases with an implicit concern for health. We performed a search in these case documents to quantify the number of times that the word health was explicitly used in this litigation. We used the case data to iden- tify climate litigation with a legal strategy, where the plaintiff relied on climate science and public health as part of a systematic challenge to a field of law. This resulted in 65 cases catego- rized as public health climate litigation, where public health was part of the litigation strategy. The primary sources for this research have been the respective case law databases of the Grantham Research Institute on Climate Change and the Environment [68], and the Sabin Center for Climate Change law [69]. We also searched ECOLEX: a data base operated by FAO, IUCN and UNEP, whose purpose is to “build capacity worldwide by providing the most com-

prehensive possible global source of information on environmental law and includes treaties, treaty decisions, legislation, and literature along with jurisprudence”. The primary databases are the most comprehensive, publicly available databases for researchers of case law in the field of Climate law. According to the methodology of the data- base provided by the Grantham Research Institute for Climate and the Environment: “The analysis covers all UN and UNFCCC parties, including the European Union, as well as a num- ber of countries, regions and territories that are not UN or UNFCCC members (e.g. Taiwan, Palestine and Western Sahara)” [70]. The focus of our research is on the role of public health in strategic climate litigation, build- ing upon the significant document pooling already contained in the chosen sources, including the translation of non-English language case documents. The databases of the Grantham Research Institute and the Sabin Center for Climate Change law are organized under a climate science agenda, with an interdisciplinary focus on climate change. Despite increasing literature on climate law, this is an emerging field, and there are limited data sources for such research. While these databases were considered relatively robust sources for the comprehensive identification of past litigation cases, it is notable that they have some limitations in their scope, as discussed in greater detail in the limitations section. Results Temporal trends The literature review yielded a total of 1641 cases of climate litigation filed between 1990 and

September 2020. As of November 2020, a total of 2069 Climate Laws and Policies were in force [71]. The numbers according to region are: (i) East Asia and Pacific– 391 (ii) Europe and Cen- tral Asia– 677 (iii) the EU– 41 (iv) Latin American and the Caribbean– 364 (v) Middle East and North Africa– 125 (vi) North America (including Canada)– 33 (vii) South Asia– 109 (viii) Sub Saharan Africa– 383 [72]. Of these 2069 Climate Laws and Policies, 1920 (93%) have been passed since 2000, and 1367 (66%) have been passed since 2010 [73]. The distribution of these cases by year is shown in Fig 1 which depicts a clear trend of increasing numbers of cases across time, with only 9 cases filed from 1990–99 and 836 cases filed from 2015–20. Not shown in Fig 1, the year the Paris Agreement came into force was piv- otal, with a sharp increase in cases after 2016. PLOS ONE Public health as a legal tool in climate litigation PLOS ONE | https://doi.org/10.1371/journal.pone.0268633 June 15, 2022 8 / 31

Additional to an increasing trend in cases, we noted explicit references to climate change became notably more frequent in the post-2000 cases. In the 1990–99 cases, climate change was seldom explicitly mentioned as the core issue, and legal arguments primarily related to broader (though inherently climate-linked) issues of environmental harm and destruction, air and water pollution, and land-use change, amongst others. Anthropocentric conceptualiza- tions of the environment as a human-serving/resource-producing asset were also notably more apparent in the 1990–99 cases. In contrast, post-2000 cases featured far more explicit references to climate change. Not only were allegations grounded in an explicit focus on climate change, but many cases, particu- larly in more recent years linked human rights (including the right to health) with de- Fig 1. Total number of climate litigation cases by time period (1990–2020). https://doi.org/10.1371/journal.pone.0268633.g001 Fig 2. Distribution of non-USA climate litigation by World Bank development category. https://doi.org/10.1371/journal.pone.0268633.g002 PLOS ONE Public health as a legal tool in climate litigation PLOS ONE | https://doi.org/10.1371/journal.pone.0268633 June 15, 2022 9 / 31

carbonization, sought increased liability for climate risk-associated financial/investment activ- ity, as well as legal attribution of personhood for the environmental, or legal accountability to future generations impacted by climate change. Compatible with this finding is the temporal trend of increasing likelihood of case-driven policy change across time. Indeed, in keeping with accelerating climate change, most of the cases which directly led to the passage of new cli- mate-friendly, environmental health-rooted, or human rights-oriented legislation or legal stat- utes occurred in the past 5 years. This trend suggests maturation of climate law. Characteristics of cases Of the 1641 cases identified, the vast majority (n = 1241) were filed in the US, with only 360 filed elsewhere. The majority of the cases pursued outside the USA (90%, n = 325) were filed in high-income countries, with only 35 (10%) filed in low- and middle-income countries (LMICs) [74] (Fig 2). The distribution of cases by plaintiff and defendant type (the actors against whom cases have been filed) for the 65 directly public health-linked climate litigation cases identified is depicted in Figs 3 and 4, respectively. With regards to plaintiff type, youth comprised the largest category, followed by govern- ment then individuals independent of interest groups. The data concerning defendant type depict an overwhelming majority of cases against governments, with fewer filed against corpo- rations. Nonetheless, when analyzing temporal trends across all cases (not only public health-

linked ones), we observed the number filed against corporations increased greatly over the past two years, (7 cases in 2019 and 3 in the first half of 2020, compared to one case in all of 2015). Diverse legal claims and arguments were put forth in the 65 directly public health-linked cases, involving a complex distribution of legal precedents on which accusations of wrongdo- ing were based. The cases were categorized into human rights, economic, and eco-centric focused arguments. Human rights claims predominate, with most plaintiffs equating assaults on health with what are deemed to be clear human rights violations (Fig 5). Fig 3. Public health-linked climate litigation cases by category of plaintiff. https://doi.org/10.1371/journal.pone.0268633.g003 PLOS ONE Public health as a legal tool in climate litigation PLOS ONE | https://doi.org/10.1371/journal.pone.0268633 June 15, 2022 10 / 31

Findings on public health-linked cases Of the 1641 cases of climate litigation identified in this review, only 65 were categorized as directly “public health-linked” on the basis of plaintiffs explicitly mentioning human health in legal argumentation and/or expressing a value for human health through emphasis on human health-environment interconnections. The status of these cases as of September 2020 is depicted in Fig 6, with 11 cases achieving success for the plaintiff, 11 cases determined for the defendant, and 25 cases still pending decision. The file years for pending cases and verdict years for decided cases are shown in Figs 7 and 8, respectively. In both, a clear temporal trend with rising frequency of both filed and decided cases is shown. Nine notable cases that occurred in the past 5 years were selected for more in-depth analysis based on their strong public health linkages. These cases are listed and summarized in chrono- logical order in Table 1, with indication of the number of times the word “health” (both Fig 4. Public health-linked climate litigation cases by category of defendant. https://doi.org/10.1371/journal.pone.0268633.g004 Fig 5. Public health-linked climate litigation cases by field of law. https://doi.org/10.1371/journal.pone.0268633.g005 PLOS ONE Public health as a legal tool in climate litigation PLOS ONE | https://doi.org/10.1371/journal.pone.0268633 June 15, 2022 11 / 31

human and environmental health) was used in the case document submitted to the court. The number of times the word “health” was explicitly used ranged widely from twice (case 6) to a maximum of 28 (case 4). Discussion The evolution of litigation as a legal tool for climate action The recent surge in climate litigation, characterized by a notable uptick in cases filed since 2015, is testament to the growing recognition of the potential value of using litigation as a tool for climate action. The rising trend in cases filed (Fig 1) indicates a growing expectation that actors ought to be held accountable for actions which wreak havoc on the environment and threaten the prospect of sustaining a climate compatible with human life. These temporal trends are generally consistent with findings from other studies which have documented a rel- atively consistent rise in both US- and non-US-filed climate litigation cases [84]. The discourse on environmental health now occurring in legal courts can also be said to represent an increased appreciation for the role of Ecosystem Services in supporting health Fig 6. Current status of public health-linked climate litigation cases (April 2020). https://doi.org/10.1371/journal.pone.0268633.g006 PLOS ONE Public health as a legal tool in climate litigation PLOS ONE | https://doi.org/10.1371/journal.pone.0268633 June 15, 2022 12 / 31

and well-being, not only in terms of material resources (“provisioning services”) but also shel- tering populations from physical harm for example purifying water (“regulating services”), maintaining planetary equilibrium (“supporting services”), and promoting spiritual and cul- tural value (“culturally enriching services”) [48]. The post-2015 surge in cases has been linked with two major 2015 events: 1) the passage of the Paris Agreement which solidified national commitments to carbon emission reduction to limit global warming to well below 2, preferably to 1.5 degrees Celsius, compared to pre- Fig 7. File year of pending public health-linked climate litigation cases. https://doi.org/10.1371/journal.pone.0268633.g007 Fig 8. Verdict year of decided public health-linked climate litigation cases. https://doi.org/10.1371/journal.pone.0268633.g008 PLOS ONE Public health as a legal tool in climate litigation PLOS ONE | https://doi.org/10.1371/journal.pone.0268633 June 15, 2022 13 / 31

Table 1. Recent public health-linked climate litigation cases. Case No. Plaintiff v Defendant Court and Year Case Filed Brief Case Description and Outcome (If Available) # Times Health Mentioned Example of Health Term Usage 1 Urgenda Foundation v State of the Netherlands [75] Netherlands Court of Appeals, 2015 (Decided 2019) Case: Appeal by Urgenda Foundation for Dutch gov’t to reduce emissions by minimum 25% before 2020 Outcome: Court order for Dutch gov’t to adopt stringent policies to reduce emissions by 25% before 2020 4 “This will result in, among other things, the significant erosion of ecosystems which will, example, jeopardise the food supply, result in the loss of territory and habitable areas, endanger health, and cost human lives.” 2 Future Generations v Ministry of the Environment [76] Supreme Court, Bogota, 2018 (Decided 2018) Case: Youth plaintiffs seek to enforce fundamental rights to a healthy environment which they claim are threatened by climate change and deforestation. Outcome: Court decided that the Amazon has personhood in law thus giving rights to nature 7 “Fundamental rights of life, health, the minimum subsistence, freedom, and human dignity are substantially linked and determined by the environment and the ecosystem.” 3 Maria Khan et al. v Federation of Pakistan [77] Lahore High Court, Pakistan 2018 Case: Lawsuit filed by Maria Khan and group of women against Pakistan gov’t for inaction on climate change, resulting in violation of fundamental rights to clean and healthy environment, climate capable of sustaining human life, equal protection

for women under the law, and no discrimination on the basis of sex Outcome: Pending 7 “The Impugned Conduct infringes the right to life and the right to dignity of the Petitioners, by violating their right to a clean and healthy environment and a climate capable of sustaining human life.” 4 Neubauer et al. v Germany [78] Federal Constitutional Court of Germany, 2020 (Decided April 2021) Case: Lawsuit filed by Neubauer and group of German youth against German gov’t for failing to uphold national obligation under Paris Agreement to limit global temperature rise to “well below 2 degrees Celsius”; appeal for German gov’t to raise GHG reduction target from 55% to 70% by 2030 Outcome: The Court held that the legislature had not proportionally distributed the budget between current and future generations. Legislature ordered to set clear reduction targets. 28 “Any increase in global temperature (e.g. +0.5°C) will above all have negative impacts on human health–this is undisputed in the scientific literature following the IPCC Special Report on 1.5°C (Annex 3).” 5 District of Columbia v Exxon Mobil Corp. [79] District of Columbia Supreme Court, USA, 2020 Case: Lawsuit filed by the District of Columbia against oil and gas companies for allegedly violating the Consumer Protection Procedures Act by misleading consumers about “the central role their products play in causing climate change” Outcome: Pending 12 “These events threaten human health, food security, agriculture, economic productivity, water supplies, national security, and labor productivity.”

6 Youth for Climate Justice v EU Member States [80] European Court of Human Rights, 2020 Case: Lawsuit filed by six Portuguese youth against 33 EU Member States for violating human rights by failing to take sufficient action on climate change; appeal for 33 EU Member States to take more ambitious action Outcome: Pending 2 “Resolution of the question of what constitutes a state’s ‘fair share’ in favour of the Applicants is vital if the objective set out in Article 2 of the Paris Agreement–of preventing “significant deleterious effects [. . .] on human health and welfare” by limiting global warming to 1.5°C–is to be achieved.” (Continued) PLOS ONE Public health as a legal tool in climate litigation PLOS ONE | https://doi.org/10.1371/journal.pone.0268633 June 15, 2022 14 / 31

industrial levels, providing more legal leverage for plaintiffs suing purely on the basis of GHG emission exceedances [85], and 2) the landmark judgement delivered in the Urgenda case where a class-action brought by 886 Dutch citizens resulted in a court order for the Dutch gov- ernment to adopt a more ambitious emission reduction target [86]. The momentum created by the success of Urgenda (Table 1, case 1) led to similar cases emerging in the domestic tribunals of several jurisdictions all over the world, ranging from Belgium to France and South Korea, beginning what has been referred to as the “new wave” of climate litigation [86]. Despite the trend in plaintiffs using litigation as a legal tool for climate action, it remains unclear, from our results and other studies [84], to what extent climate litigation generates new government legislation or policy. This uncertainty is especially pronounced among LMICs, where the frequency of filed cases remains extremely low, representing only 2% (n = 35) of the 360 non-US cases. Notwithstanding the relatively high volume of litigation, Table 1. (Continued) Case No. Plaintiff v Defendant Court and Year Case Filed Brief Case Description and Outcome (If Available) # Times Health Mentioned Example of Health Term Usage 7 Juliana v United States [81] United States Court of Appeals for the Ninth Circuit, 2015 (decided 2020) Case: In a split decision, the Ninth Circuit Court of Appeals ruled that young people and other plaintiffs asserting a claim against the federal government for infringement of a Fifth Amendment due

process right to a “climate system capable of sustaining human life” did not have Article III standing. Outcome: Decided against the Plaintiff. Petition for re- hearing has been submitted. 9 “In these proceedings, the government accepts as fact that the United States has reached a tipping point crying out for a concerted response—yet presses ahead toward calamity. It is as if an asteroid were barreling toward Earth and the government decided to shut down our only defenses. Seeking to quash this suit, the government bluntly insists that it has the absolute and unreviewable power to destroy the Nation” STATON, District Judge, dissenting against the majority ruling. 8 UN Human Rights Committee Views Adopted on Teitiota Communicatio [82] United Nations Human Rights Committee, 2015 (decided 2020) Case: On September 15, 2015, Teitiota filed a communication with the UN Human Rights Committee, alleging that New Zealand had violated his right to life under the International Covenant on Social and Political Rights. The New Zealand Supreme Court had decided that the applicant did not qualify as a climate refugee under international human rights law. The Committee ruled that an arbitrary deprivation of life must be personal rather than rooted in the general conditions of the receiving state. Outcome:Case dismissed on merits. 21 “It would indeed be counterintuitive to the protection of life, to wait for deaths to be very frequent and considerable; in order to consider the threshold of risk as met. It is the standard upheld in this Committee,

that threats to life can be a violation of the right, even if they do not result in the loss of life. It is should be sufficient that the child of the author has already suffered significant health hazards on account of the environmental conditions”, dissenting judgement. 9 Milieudefensie et al. v Royal Dutch Shell [83] Netherlands, The Hague, District Court, 2019 Case: This case built on the landmark Urgenda decision which found that the Dutch government’s inadequate action on climate change violated a duty of care to its citizens. In the suit against Shell, plaintiffs extend this argument to private companies, given the Paris Agreement’s goals and the scientific evidence regarding the dangers of climate change.Outcome: Defendant Shell must reduce carbon emissions by 45% by 2030 relative to 2019. 77 “Humans depend on healthy and sufficiently vital ecosystems for their lives and well being, that can provide such ecosystem goods, functions, and services that humans need for their existence, in a sufficiently reliable manner. Climate change is a threat to ecosystems and therefore a threat to human life and well- being” https://doi.org/10.1371/journal.pone.0268633.t001 PLOS ONE Public health as a legal tool in climate litigation PLOS ONE | https://doi.org/10.1371/journal.pone.0268633 June 15, 2022 15 / 31

North America (including Canada) has passed only 33 climate laws and policies, which is sig- nificantly less than the 677 passed in Europe and Central Asia. Whilst outside the scope of this study, analyzing the relationship between existing legal frameworks, breaches of these and numbers of cases brought before courts is an area worthy of further research. The total rise in cases is due largely to the recently documented increases in annual liti- gation occurring in the US and in a select few other jurisdictions including Australia, New Zealand, the European Union, Spain, and the United Kingdom [87]. However, litigation may indicate that there are political, cultural or other obstacles to climate justice in a particular jurisdiction. In Juliana v United States (Table 1, case 7), despite a 38-page submission by lead- ing public health experts stating that “without significant intervention, this new era will come to define the health of an entire generation”, the court declined to directly adjudicate on cli- mate change. The court explained the adjudication did not refute the science, rather recoiled from passing a political ruling in the following statement: “There is no justiciable ‘controversy’ when parties seek adjudication of a political question. . . It is not the province of the judiciary to make the policy decisions required to grant Plaintiffs the relief they seek. Nor may this Court direct other branches of government to overhaul their fossil fuel, agriculture, logging, and family planning policies to address climate change. To suggest otherwise is to overlook

‘the separate and distinct constitutional role’ of the judiciary” [81]. This ruling may yet be overturned on appeal, but the judges of this case interpreted the constitution so as to hold that climate policy must arise from the legislative and political process, and not the judiciary. Scholars have highlighted that the role of the global South in climate litigation should not be overlooked. We find this contention meritorious because, despite the relatively low num- bers of cases from LMICs, many, most notably in Colombia, Ecuador, Bangladesh and India, were eco-centric cases brought against powerful companies. The important context here is that the 52 LMICs produced a fraction of the total 2020 CO2 emission [88], yet, they dispro- portionately bear the brunt of climate change impact and a higher risk of climate-driven health threats. Therefore, it is particularly salient for LMICs to use legal arguments based on climate injustice and vulnerability. Finally, our finding that a growing number of cases are being brought by individuals (for instance as class-action lawsuits) provides further evidence of an increasingly “bottom-up approach to climate governance” [86]. From a pro-health standpoint, this can be viewed as an indication of rising public awareness of the threat of climate change and an accompanying realization by individuals and civil society of their democratic right to hold corporations and governments accountable for actions which infringe their rights to a healthy environment.

Our analysis of litigation outcomes shows marked heterogeneity. Increased pressure on legisla- tures and corporations to change their behaviour is clearly evident, yet many courts remain slow to take the fullest action that the science calls for. Trends suggest this pressure is likely to increase this decade. Still, early successes particularly in the field of human rights give reason for optimism; amassing a folio of successful litigation that translates to pro-health and pro-environment pol- icy can be expected to motivate others to bring forward cases citing egregious occurrences or prospects of harm. Temporal and geographic trends in legal argumentation Climate change as a peripheral vs. core issue. Climate Change Litigation (CCL) has gained prominence over the past three decades as a “governance mechanism for addressing climate change” [61]. In the late 1980s and early 1990s in the United States, climate legal action began as a means to hold actors accountable for activities knowingly contributing to GHG PLOS ONE Public health as a legal tool in climate litigation PLOS ONE | https://doi.org/10.1371/journal.pone.0268633 June 15, 2022 16 / 31

emissions exceeding national guidelines [61]. Our database searches identified that between 1986 and the end of May 2020, a total of 1,587 cases of CCL worldwide had been brought before courts, with 1,213 (76%) cases in the United States and 374 cases in 36 other countries and eight regional or international jurisdictions. Out of this total we found 65 directly linked public health cases. With the mounting climate crisis unfolding, CCL continues to be a grow- ing field of law that intersects International and National Environmental Law, International Human Rights Law, and a complex range of statutes, regulations, and legal principals spanning national, subnational and, in some countries, constitutional law. One of the most notable temporal trends we observed was the increasing frequency of cli- mate change being framed as the core issue. Litigation is evidently evolving as a specific tool for climate legal action. Early cases tended to present environmental destruction as the central concern and framed climate change as a peripheral or secondary issue. The 2020 climate liti- gation snapshot found climate change to be “at the centre of the legal argument” in about 41% of cases, whereas in the remaining 59% climate change was classified as a “peripheral issue” [61]. The increasing discussion of climate change as a core issue suggests the ‘legal main- streaming’ of climate change, whereby the adaptation, mitigation, and regulation of industry, becomes a matter of business and financial law, discussed in detail below.