Results. Health has been a critical consideration in key climate lawsuits, but in a minority of cases. Litigants have presented health arguments most frequently and effectively in terms of airborne exposures. Health impacts have typically been used to gain standing and argue that the evidence for government actions is insufficient.

Methods. We coded US local, state, and federal court decisions relating to climate change and coal-fired power plants from 1990 to 2016 (n = 873) and qualitatively investigated 139 cases in which litigants raised issues concerning the health impacts of climate change. We also conducted 78 interviews with key litigants, advocates, industry representatives, advising scientists, and legal experts.

Climate change exacerbates existing health threats and creates new public health challenges. It is considered by many to be the biggest threat to public health in the 21st century.1 Climate change results in elevated temperatures that increase the risk of heat-related morbidity and mortality; degraded air quality and related cardiopulmonary respiratory disease; diseases transmitted through food, water, and disease vectors; and stresses to mental health.2 These effects will only become more severe without significant reductions in greenhouse gases (GHGs) worldwide. Despite the need for governmental action to address climate-related health risks, Congress has not yet passed legislation that specifically targets climate change. The Trump administration has forcefully begun to undo executive actions designed to abate climate threats that were undertaken by the Obama administration. Unless these dynamics change, those concerned about the health impacts of climate change are likely to increasingly rely on the judicial branch to force administrative agencies to consider the health impacts of climate change in their decision-making processes, or to compel both governmental and private organizations to limit GHGs or otherwise address the impacts of climate change.

Addressing climate change also often results in regulation of airborne pollutants, such as those emitted by coal-fired power plants (CFPPs). Airborne pollutants associated with power production are estimated to cause 200 000 premature deaths in the United States annually, often disproportionally burdening communities near emission sources.3,4 Reducing carbon dioxide (CO2) emissions, especially from power plants and by closing or repowering CFPPs would also reduce copollutants such as particulate matter, sulfur dioxide, or ozone precursors (which are often referred to as criteria pollutants under the Clean Air Act [CAA]), that have been linked to premature mortality and respiratory illnesses.

Although the CAA authorizes the US Environmental Protection Agency (EPA) to limit emissions of both CO2 and other air pollutants, nongovernmental organizations have resorted to the courts to prompt the EPA to carry out its responsibilities to protect public health from air pollution. They have also brought suits directly against sources alleged to be in violation of applicable emission standards or permit provisions. Historically, litigants concerned about public health and welfare, such as those attempting to address the adverse consequences of smoking5 and those concerned with the adverse health effects of exposure to toxic substances, have also turned to the courts when efforts by other branches of government have stalled.6

Litigants seeking to address public health and environmental exposures through the courts have met with mixed success. For example, in the case of climate litigation, approaches relying on theories such as the common law have not succeeded, largely because of the difficulty facing plaintiffs in establishing that a particular emitter or set of emitters caused the specific harm suffered by the plaintiff. Resolution of these types of suits may be incapable of effectively mitigating climate-related health threats.7–9 Litigants have been more successful when they requested that courts review allegedly inadequate governmental consideration of or responses to climate change. Although some more localized climate regulations were in place before 2007, the viability of the CAA as a mechanism for restricting GHG emissions was established that year in Massachusetts v. EPA, in which the Supreme Court held that CO2 qualifies as an air pollutant that the EPA is required to regulate if it finds that such emissions “cause, or contribute, to air pollution which may reasonably be anticipated to endanger public health or welfare.”10 The Obama administration’s EPA subsequently issued a finding (known as the endangerment finding) that emissions of GHGs, including CO2, from new motor vehicles do cause or contribute to public health or welfare endangerment.11

Litigants have since sued government agencies, claiming that they have afforded insufficient consideration of climate change and its effects in making decisions to pursue particular projects, such as building infrastructure. Many of these lawsuits have been filed under the National Environmental Policy Act (NEPA) or equivalent state laws such as the California Environmental Quality Act. NEPA requires federal agencies to prepare an environmental impact statement when they propose major federal action that may significantly affect the environment, although agencies often prepare less comprehensive environmental assessments for proposals anticipated to have lesser effects.12

The regulations issued by the Council on Environmental Quality (the agency responsible for supervising NEPA compliance across the federal government) define effects to include health effects directly or indirectly caused by a project.13 Litigants have also relied on the Endangered Species Act to challenge agencies’ allegedly inadequate consideration of climate change, but those suits are much less likely to implicate public health concerns. All of these lawsuits turn on judicial evaluation of the administrative record developed by an agency in making a decision. The development of this record, which includes not only input by agency scientists but also comments submitted by any other interested person, is the principal opportunity to ensure that the scientific evidence relating to the health impacts of climate change is before the court deciding on the adequacy of the agency’s evaluation of climate change. Litigants have had considerable success in halting or delaying agency projects on the basis of insufficient analysis of climate impacts.

Although public health concerns may be important to climate litigation, how the courts take those concerns into account is not well understood. In addition, limited research has systematically investigated how scientific evidence and issues of substantiating risks play a role in cases.14 We sought to fill this gap by examining the role of health in all climate lawsuits and CFPP cases from 1990 to 2016. We included CFPP cases because CFPPs are the biggest contributor to climate change in the United States. We inquire, first, whether health issues are being raised in climate litigation; second, how health issues are handled in court; and, third, how the evidence about health affects judicial decisions. Although the number of cases involving health is not large enough to be able to draw firm statistical conclusions about how relying on adverse health effects affects the likelihood of success in climate lawsuits, this research provides an understanding of the kinds of cases in which health is an important consideration, how litigants raise these concerns, and the prospects for an increased focus on health issues in the future to contribute to more successful efforts to invoke judicial assistance in achieving climate policy objectives. As such, it articulates how health may or may not continue to play a role in judicial disposition of climate change cases.

METHODS Section: Choose Top of page Abstract METHODS << RESULTS DISCUSSION PUBLIC HEALTH IMPLICATION... REFERENCES We conducted a mixed-methods study to answer our research questions. First, we constructed a database of all domestic climate change lawsuits and CFPP cases from 1990 through 2016 by using the listing of cases from the Columbia University Law School Sabin Center for Climate Change Litigation Chart (n = 873). These cases were selected on the basis of the following definition: any piece of federal, state, tribal, or local administrative or judicial litigation in which the party filings or tribunal decisions directly and expressly raise an issue of fact or law regarding the substance or policy of climate change causes and impacts or relates to coal-fired power plants.15(p27) We characterized each case by means of 19 variables (for details, see the supplemental materials, available as a supplement to the online version of this article at http://www.ajph.org). All cases were coded by the type of law being challenged, level and type of science used, climate topic, and outcome. We also conducted a qualitative analysis of all cases that referenced health (n = 139) and quantitatively characterized these cases by type of health issue and level of health involved in the argument. Dismissed cases were ones in which the court did not address the merits of the legal issue implicating climate change. Denied cases were ones in which the court considered the legal issues raised by the plaintiffs but rejected them. Partially granted or granted cases included cases in which the plaintiff succeeded in gaining at least partial approval from the court for the plaintiff’s claims.16 Second, we conducted in-depth interviews with plaintiffs, defendants, advising scientists, and advocates involved in key cases (n = 78). Our initial interviewee sample included respondents from environmental nongovernmental organizations, industry associations, government agencies, private law firms, advocates, and independent scientists. Interviews were mostly conducted in person and then on the phone when necessary. They were recorded and transcribed, then deidentified to maintain anonymity. All qualitative data were entered into NVivo (version 10, QSR International, Burlington, MA), coded, and analyzed. Coding was based on research and interview questions, including issues of framing, causation, scientific certainty, and legal approach.

RESULTS Section: Choose Top of page Abstract METHODS RESULTS << DISCUSSION PUBLIC HEALTH IMPLICATION... REFERENCES We identified 2 main findings regarding health cases. First, relying on evidence of the impacts of climate change on public health risks in litigation brought under the CAA appears to make an issue more compelling to the courts by building the foundation for a powerful story. Second, health-related arguments supported litigants in gaining standing to bring a case, without which they would not have been able to advance their substantive contentions in support of the relief they sought. For coding purposes, cases often involved more than 1 climate-related topic, and we selected one as the primary topic when this was clear. For the 139 cases with health concerns, common climate-related topics involved multi-issue arguments (n = 52), CFPPs (n = 22), and other air quality impacts (n = 47). Air quality cases generally addressed the 6 criteria air pollutants for which the EPA has adopted national ambient air quality standards under the CAA. Health was infrequently raised in cases concerning water (n = 5), biodiversity (n = 1), and energy (n = 0). It is interesting to note that almost all cases involving health were aimed at mitigation of climate change (91%) rather than adaptation or responding to the impacts of climate change. Most cases in which litigants raised health as a concern were brought by litigants seeking to require the defendant to take some action to address climate change (129 of 139), such as by limiting GHG emissions or taking climate change into account in project design. Fourteen cases involved opposition to regulation or further consideration of climate change, and 2 cases were neither supportive of nor opposed to further climate-related action. In the following sections, we explore why litigants included health-related issues in the concerns they raised and how strategies within these health-related cases led to specific outcomes. Motivation for and Context of Health-Related Claims The 139 cases in which litigants relied on health concerns to support their claims for relief arose primarily under the CAA (n = 45; 32%), California Environmental Quality Act (n = 40; 29%), and NEPA (n = 24; 17%; Table 1). Litigants concerned about health assert claims relating to the CAA more than any other statute because the CAA’s principal goal is protection of public health, and Massachusetts v. EPA made it an appropriate vehicle for restricting GHG emissions. Reliance on the effects of climate change on human health also provides a tangible, and perhaps compelling, way of underlining the need for and significance of addressing climate change that may be salient both to the courts and to the public. TABLE 1— Frequency of Laws Challenged for Cases Involving Health, Compared With Those Not Involving Health: United States, 1990–2016 Law Health, No. (%) Nonhealth, No. (%) CAA 45 (32) 199 (28) NEPA 24 (17) 107 (15) CEQA 40 (29) 81 (12) State 9 (6) 73 (10) Other 21 (15) 239 (34) Total 139 (100) 699 (100) One interviewee explained why there is such an abundance of air cases and how health is central to them: The Clean Air Act is the straightest shot especially with the court having held [in Massachusetts v. EPA], as it properly should have, that CO2 is an air pollutant just like CO or SO2. . . . Molecules put into the air by the act of humans combusting fuels or other industrial operations and air pollutants must be regulated under various parts of the Clean Air Act if [the statutory test triggering a mandate to regulate emissions that] may reasonably be anticipated to endanger public health or welfare is met. Litigants often attempted to link the planning or development of infrastructure, or the present and future operation of a CFPP, to the adverse health effects of climate change. For example, in the case of Public Service Co. of New Mexico v. EPA, the EPA ordered New Mexico’s largest electric utility to spend $750 million to retrofit a CFPP to bring its facility, whose emissions were alleged to be adversely affecting the health of local populations, into compliance with the CAA. The utility challenged the order, but the Court of Appeals for the 10th Circuit rejected the challenge without comment.17 Litigants are sometimes motivated to include health allegations in climate cases because they make the consequences of unabated climate change tangible and may increase the chances that courts will grant the relief sought by satisfying the substantive criteria needed to achieve success on the legal merits of the claim. When asked what kinds of cases were most effective, one interviewee said, Cases with very compelling human stories . . . like a coal plant burdening lots of neighborhoods with massive amounts of pollution. . . . One example [is a] . . . company [that] ran a coal plant in Nevada adjacent to a tribal land, the Moapa Band of Paiute Indians. In this case, litigants made the case that people in their community had long been getting sick from their exposures. These kinds of concerns combined with those related to climate change represented a compelling story and a good reason to litigate this case. Why Health Cases Lead to Wins or Losses We found that cases in which health was an issue had a win rate nearly the same as that for nonhealth cases (31% and 30%, respectively; Table 2). This finding suggests that the presence of allegations of health-related impacts of climate change makes no difference in case outcomes. Litigants sometimes relied on allegations of climate-related adverse health impacts to show the injury needed to support standing to sue. Once a plaintiff has crossed the standing hurdle, the plaintiff may make legal claims that are not related to the nature of the injury relied on to support standing. As a result, a plaintiff with standing can seek relief that may provide a wider range of health benefits (such as shutting down a power plant that emits harmful criteria pollutants or halting an infrastructure project that will damage the natural environment) than those that would result from eliminating the health impacts that provided the basis for standing. TABLE 2— Frequency of Outcomes for Cases Involving Health, Compared With Those Not Involving Health: United States, 1990–2016 Outcome Health, No. (%) Nonhealth, No. (%) Dismissed 35 (36) 175 (35) Denied 32 (33) 173 (35) Granted or partially granted 30 (31) 148 (30) Total 97 (100) 496 (100) In some cases, plaintiffs have argued that government agencies have failed to adequately take account of the scientific evidence that allowing a project to proceed would result in adverse health effects because of the project’s impact on climate change or the impact of climate change on the project. If plaintiffs prevail in such litigation, courts typically remand for further agency action and may prevent project implementation in the meantime. For example, in Montana Environmental Information Center v. US Office of Surface Mining (2017 WL 3480262; D. Mont. 2017), the court concluded that the Office of Surface Mining failed to adequately consider the adverse effects of coal combustion, including the adverse public health effects, in approving the expansion of an underground coal mine. In many of these health cases, litigants called for more thorough investigation of the health effects of the action challenged on the basis of a lack of evidence regarding those health effects or a debate regarding research methods or the role of expert testimony. The courts generally addressed these alleged deficiencies or debates in setting forth the rationale for their rulings, demonstrating that evidence about health is important to case outcomes. Of the lawsuits that involved health, 40% involved legal arguments that included discussion of climate science, whereas suits that did not involve health relied on climate science slightly less (32% of the time; Table 3). Only occasionally was climate science a central part of the decision. Health and nonhealth cases used climate science centrally at relatively similar rates (13% and 11%, respectively), and health cases used other sciences centrally 14% of the time and nonhealth cases used other sciences only 8% of the time (data not shown). TABLE 3— Frequency of Use of Climate Science for Cases Involving Health, Compared With Those Not Involving Health: United States, 1990–2016 Role of Climate Science in Decision Health, No. (%) Nonhealth, No. (%) Not discussed 81 (60) 468 (68) Discussed, but not central 37 (27) 146 (21) Discussed and central to decision 17 (13) 77 (11) Total 135 (100) 691 (100)

DISCUSSION Section: Choose Top of page Abstract METHODS RESULTS DISCUSSION << PUBLIC HEALTH IMPLICATION... REFERENCES Litigation has become a central mechanism for seeking government action on climate change as Congress and the executive branch withdraw from this policy arena and as litigants perceive the courts to be the most responsive forum. Litigants have resorted to the courts to try to force government agencies to take better account of the climate impacts of their decisions, and in a considerable number of cases they have claimed that the immediate and long-term effects on public health demand more careful scrutiny. Understanding the dynamics of how health concerns are addressed or ignored in these suits is a way to better understand how efforts by those concerned about the public health effects of climate change can use litigation to address those concerns. Public health issues are often central to suits under the CAA, and they were also relevant to some cases that alleged insufficient consideration of climate impacts by government agencies proposing projects likely to affect or be affected by climate change. In all of these contexts, the strength of the scientific evidence mustered to support litigants’ challenges is likely to be an important determinant of case outcomes. Arguments about health were raised in a minority of all of the climate-related cases in our database, especially in cases dealing with renewable energy and energy efficiency. The absence of health claims in these cases is surprising and potentially an oversight on the part of advocates and litigators because evidence regarding the costs and benefits of energy development can play a role in energy-related approvals. For example, increased energy efficiency lowers the rate of GHG emissions, which reduces the health impacts of climate change to which GHG emissions contribute.18 The minimal reliance on health-related impacts in natural gas extraction cases may also reflect an oversight by litigators. Several such cases in the database that centered on claims about contaminated water and used health as a central argument were won by plaintiffs seeking improved protections for local communities. Although natural gas combustion generates less GHG than coal, it still contributes to climate change, and therefore has adverse public health impacts of the kind discussed in the EPA’s endangerment finding.

PUBLIC HEALTH IMPLICATIONS Section: Choose Top of page Abstract METHODS RESULTS DISCUSSION PUBLIC HEALTH IMPLICATION... << REFERENCES This research should be of interest to public health researchers, advocates, and litigants because it demonstrates how climate change lawsuits may be used to protect public health, the ways in which that approach can be effective, the limitations to date on the use of this vehicle to address climate change, and possible further opportunities to rely on the courts to minimize the adverse health effects of climate change. Public health researchers, advocates, and others can use the judicial branch in dealing with an important social public health–related problem for which legislative and executive action is unlikely to be forthcoming in the near future, at least at the federal level. Courts can play a key role in driving change by requiring agencies to take climate change into account under laws such as NEPA and similar state laws. As the health impacts of climate change become better established, public health experts may be able to raise the salience of the links between climate change and adverse health effects by providing evidence to agencies or courts about the nature and importance of those links. The courts have been receptive to such efforts, at least in some contexts. In addition, public health experts and practitioners can play a role in generating evidence and expert opinion important to courtroom decisions. The proportion of cases in which litigants rely on science to support legal theories that force action to respond to climate change is increasing. Indeed, as advances in areas such as attribution science permit the identification of stronger links between health impacts and the contributions of specific activities to climate change, opportunities to use litigation as a tool to reduce those impacts are likely to increase. Future cases might involve the health implications of diverse energy development pathways and the impacts of climate change-related extreme weather events. Further research is necessary to identify exactly what kind of science is most likely to be influential in these and other climate lawsuits.

ACKNOWLEDGMENTS This material is based upon work supported by the National Science Foundation (grant 1534590). We thank the Columbia University Sabin Center and Michael Gerrard for providing access to the litigation database, and all the interviewees who participated in this research. We appreciate the assistance of William Davies in the research process.

HUMAN PARTICIPANT PROTECTION We received approval for this study from the institutional review board of the Milken Institute School of Public Health at George Washington University.

REFERENCES Section: Choose Top of page Abstract METHODS RESULTS DISCUSSION PUBLIC HEALTH IMPLICATION... REFERENCES <<

References

1. Costello A , Abbas M , Allen A , et al. Managing the health effects of climate change . Lancet . 2009 ;373(9676): 1693 – 1733 . Crossref, Medline, Google Scholar



2. Crimmins A , Balbus J , Gamble JL , et al. , eds. The Impacts of Climate Change on Human Health in the United States: A Scientific Assessment . Washington, DC : US Global Change Research Program ; 2016 . Crossref, Google Scholar



3. Caiazzo F , Ashock A , Waitz IA , Yim SHL , Barrett SRH . Air pollution and early deaths in the United States. Part I: quantifying the impact of major sectors in 2005 . Atmos Environ . 2013 ;79: 198 – 208 . Crossref, Google Scholar



4. Liu X , Lessner L , Carpenter DO . Association between residential proximity to fuel-fired power plants and hospitalization rate for respiratory diseases . Environ Health Perspect . 2012 ;120(6): 807 – 810 . Crossref, Medline, Google Scholar



5. Mather L . Theorizing about trial courts: lawyers, policymaking, and tobacco litigation . Law Soc Inq . 1998 ;23(4): 897 – 940 . Crossref, Google Scholar



6. May JR . Civil litigation as a tool for regulating climate change: an introduction . Valparaiso University Law Rev . 2012 ;46: 357 . Google Scholar



7. Posner E . Climate change and international human rights litigation: a critical appraisal . University PA Law Rev . 2007 ;155: 1925 . Google Scholar



8. Kysar D . What Climate Change Can Do About Tort Law. Faculty Scholarship Series 3849. New Haven, CT: Yale Law School; 2011. Google Scholar



9. Comer v. Murphy Oil Co., 585 F3d 855 (5th Cir. 2009), 607 F3d 1049 (5th Cir. 2010). Google Scholar



10. Massachusetts v. EPA, 549 US 497 (2007). Google Scholar



11. Endangerment and Cause or Contribute Findings for Greenhouse Gases Under Section 202(a) of the Clean Air Act. Fed. Reg. 2009;74(66):496. Google Scholar



12. Cooperation of agencies; reports; availability of information; recommendations; international and national coordination of efforts, 42 USC §4332(2)(C) (1970). Google Scholar



13. Effects, 40 CFR §1508.8 (2017). Google Scholar



14. Smith J , Shearman D . Climate Change Litigation: Analysing the Law, Scientific Evidence and Impacts on the Environment, Health and Property . Adelaide, South Australia, Australia : Presidian Legal Publications ; 2006 . Google Scholar



15. Markell D , Ruhl JB . An empirical assessment of climate change in the courts: a new jurisprudence or business as usual? Fla Law Rev . 2012 ;64(1): 15 – 86 . Google Scholar



16. McCormick S , Simmens S , Glicksman R , et al. Science in litigation, the third branch of US climate policy . Science . 2017 ;357(6355): 979 – 980 . Crossref, Medline, Google Scholar



17. Public Service Co. of New Mexico v. EPA (10th Cir. 2012). Google Scholar

