Hot Times in the High Court
Ruling could drive climate-change policy for years to come.


Jonathan H. Adler

Congress has discussed and debated the issue of global warming for years, consistently refusing to adopt regulatory controls on the emission of carbon dioxide and other greenhouse gases. Despite this fact, a divided Supreme Court decided Monday that the Environmental Protection Agency has untapped authority to regulate greenhouse-gas emissions from new motor vehicles under the Clean Air Act. The Court’s decision in Massachusetts v. EPA makes federal regulation of carbon emissions a near-absolute certainty, and not just from cars and trucks. It also ensures that federal courts will retain a hand in climate-change policy for many years to come.

The legal controversy began in 1999 when a handful of environmentalist groups petitioned the EPA to regulate emissions of carbon dioxide and other greenhouse gases from new motor vehicles. The Clinton administration accepted the argument that the EPA had such authority, but declined to act on it. At the time, I speculated that the EPA was hoping a federal court would force its hand, thereby reducing and political costs to initiating new emissions regulations unilaterally. Ever since a Democratic Congress had rejected the Clinton-Gore energy-tax proposal, the administration was reluctant to address global warming head on.

After the Bush administration took over, the environmentalist groups repeated their call for action. Joined by several state attorneys general, they prepared to sue. In response, the Bush EPA formally rejected the initial petitions on the grounds that the EPA lacked the legal authority to regulate greenhouse gases without express approval from Congress. Although there is language in the Clean Air Act that could be applied to greenhouse gases, these provisions were designed to address conventional air-pollution problems, such as soot and smog, rather than control global atmospheric pollutants. Even if it the EPA such authority, the Bush EPA argued, it would be unwise to do so given scientific uncertainty and the need for coordinated international action on climate change.

Now that the EPA had taken official action, Massachusetts and the other petitioners filed suit, seeking a federal court order to force the adoption of regulations Congress had never anticipated or approved. The U.S. Court of Appeals for the D.C. Circuit rejected the environmentalist claims, albeit in a highly fractured way. The three judges on the D.C. Circuit panel each authored his own opinion on how the case should be resolved. By this point Supreme Court review was inevitable.

In Massachusetts v. EPA, the Court held, 5-4, that (a) states have standing to sue the EPA alleging injuries from climate change, (b) the EPA has the authority to regulate greenhouse gases as “pollutants” under the Clean Air Act, and (c) the EPA did not adequately justify its decision not to regulate greenhouse-gas emissions from motor vehicles under the act. On remand, the EPA must ground its decision whether to regulate greenhouse gas emissions on the nature and magnitude of the risk posed by climate change. Given the Court’s opinion, and the EPA’s own prior statements about global warming, the agency is left with little choice but to begin the process of regulating greenhouse gases.

Justice John Paul Stevens wrote the majority opinion for himself, the Court’s other three liberals, and Justice Anthony Kennedy, who is rapidly taking to the swing-justice role vacated by retired Justice Sandra Day O’Connor. Chief Justice John Roberts and Justice Antonin Scalia wrote dissents, joined by Justices Clarence Thomas and Samuel Alito.

Justice Stevens began his opinion recounting the seriousness of the threat posed by climate change, and the number of states and activist groups that asked the Court to enter the climate-policy debate. As Justice Stevens acknowledged, scientists were only beginning to study climate change when the Clean Air Act was adopted. The provisions at issue in this case were written to address urban air pollution problems, such as soot and smog, not to regulate the earth’s thermostat. When it came to global warming, Congress repeatedly authorized scientific research and non-regulatory measures, but consistently rejected the imposition of regulatory controls. No matter, Justice Stevens reasoned, for Congress adopted expansive and flexible language that could be easily applied to impose unforeseen policies such as federal limits on carbon-dioxide emissions from new cars and trucks.

To be fair, the arguments accepted by Justice Stevens have a superficial plausibility. Under Section 202(a)(1) of the Clean Air Act, the EPA is required to regulate automotive emissions of air pollutants that “in his [the EPA administrator’s] judgment cause, or contribute to, air pollution which may reasonably be anticipated to endanger public health or welfare.” At first blush, this would seem to apply to greenhouse gases. Yet accepting this premise would not only require new restrictions on automobiles, as the act contains equivalent language in its provisions on urban air pollution. This means the EPA could soon be forced to require metropolitan areas to meet ambient air quality standards for a global atmospheric pollutant, making an absurdity out of many of the law’s substantive provisions (not to mention giving the EPA and state regulators a Sisyphusean task.)

Greenhouse gases are the most ubiquitous by-product of modern industrial society, and the Court’s statutory interpretation will inevitably force such broader federal regulation. Lawsuits seeking this result have already been filed by some of the same states and organizations that litigated Massachusetts v. EPA. Yet if Congress sought to impose such far-reaching regulations, it is simply implausible that it would leave such a mammoth issue unaddressed in the text of the act, despite repeated legislative debates over precisely this question.

If Justice Stevens’s arguments are correct, many of the provisions added to the Clean Air Act in 1990 were surplusage, as the EPA already had ample authority to address emerging concerns such as stratospheric ozone depletion and acid rain. Clearly Congress felt differently. Every time in the past that Congress sought to regulate such regional or global pollutants, it recognized the need to enact new provisions, and that is precisely what it did. Moreover, Congress has repeatedly rejected the authorization of regulatory controls on greenhouse gases, explicitly denying the EPA authority to expend taxpayer funds on preparing to regulate greenhouse gas emissions when some feared the Clinton Administration would try and do just that. As recently as 2005 the Senate adopted a resolution calling upon Congress to adopt measures to limit emissions of greenhouse gases. If Congress had already delegated authority to regulate greenhouse gases to the EPA, such resolutions would be wholly unnecessary.

A threshold question was whether the Court even had jurisdiction to hear the case in the first place. Under Article III of the Constitution, plaintiffs must have “standing” before a federal court can hear their claims. This means that plaintiffs must show that they have actually suffered a concrete and particularized harm that the court has the power to redress. This is easy to do when a factory fouls the local air or pollute a stream. It is much more difficult when ubiquitous emissions, such as carbon dioxide, disperse throughout the earth’s atmosphere and are anticipated to have global effects over a span of decades. The fact that climate change is a global concern that affects us all was one more reason to leave the question to elected legislators and treaty negotiators, rather than to force it on the judiciary.

The Court concluded that the state of Massachusetts had standing yet here, as on the other issues, the justices were narrowly divided. Chief Justice Roberts wrote a powerful dissent on behalf of four of the justices, disputing the legal basis for standing. According to Roberts, fears of climate change are a perfect example of the sort of generalized political grievance that should be addressed by the people’s elected representatives in Congress and the executive, rather than by unelected judges in federal courts.

Justice Stevens’s majority opinion adopted the somewhat novel argument that when states sue the federal government to force regulatory action they are “entitled to special solicitude” because they defend “quasi-sovereign interests.” As Chief Justice Roberts demonstrated in his dissent, this conclusion lacked any foundation in prior opinions of the Court. The only real authority cited by Justice Stevens was a 1907 case in which the issue of standing was not even an issue, and the primary significance of state participation was that it altered the range of remedies the Court would allow. In the process, Justice Stevens almost certainly lowered the standing bar for future environmental litigants.

Global warming and the various policies proposed to address it are issues of unquestionable public importance. Yet that does not mean the Supreme Court needed to get involved. As Chief Justice Roberts opened his dissent:

Global warming may be a “crisis,” even “the most pressing environmental problem of our time.” . . . Indeed, it may ultimately affect nearly everyone on the planet in some potentially adverse way, and it may be that governments have done too little to address it. It is not a problem, however, that has escaped the attention of policymakers in the Executive and Legislative Branches of our Government, who continue to consider regulatory, legislative, and treaty-based means of addressing global climate change.


Now that the Supreme Court failed to heed this message, climate-change litigation is sure to continue. In Massachusetts v. EPA the Supreme Court did not so much as resolve the climate-change debate, as ensure that federal courts will play a role in that debate for years to come.

 Contributing Editor Jonathan H. Adler is professor of law and director of the Center for Business Law & Regulation at the Case Western Reserve University School of Law. He participated in an amicus brief in Massachusetts v. EPA filed by the Cato Institute.