摘要：Objectives. To examine how the courts, which play a critical role in shaping public policy, consider public health in climate change and coal-fired power plant lawsuits. 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. 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. Conclusions. The courts represent a pivotal branch of government in shaping climate policy. Increasing inclusion of health concerns in emergent areas of litigation could help drive more effective climate policymaking. 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 smoking 5 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.
