Some interesting excerpts from the Supreme Court global warming opinion

Massachusetts v. EPA:

(Majority opinion)

Notwithstanding the seriouscharacter of that jurisdictional argument and the absence of any conflicting decisions construing §202(a)(1), theunusual importance of the underlying issue [climate change] persuaded us to grant the writ.
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In essence, EPA concluded that climate changewas so important that unless Congress spoke with exacting specificity, it could not have meant the agency toaddress it.
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The agency began by recognizing that the concentration of greenhouse gases has dramaticallyincreased as a result of human activities, and acknowledgedthe attendant increase in global surface air temperatures. Id., at 52930. EPA nevertheless gave controlling importance to the NRC Report’s statement that a causal linkbetween the two “‘cannot be unequivocally established.’”

The agency furthermore characterized any EPA regulation of motor-vehicle emissions as a “piecemeal approach” toclimate change, id., at 52931, and stated that such regulation would conflict with the President’s “comprehensive approach” to the problem, id., at 52932. That approach involves additional support for technological innovation, the creation of nonregulatory programs to encourage voluntaryprivate-sector reductions in greenhouse gas emissions, and further research on climate change—not actual regulation. Id., at 52932–52933. According to EPA, unilateral EPA regulation of motor-vehicle greenhouse gas emissions might also hamper the President’s ability to persuade key developing countries to reduce greenhouse gas emissions. Id., at 52931.
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[The lower court concluded that] it was reasonable for EPA to base its decision on scientific uncertainty as well as on other factors, including the concern that unilateral regulation of U. S. motor-vehicle emissions could weaken efforts to reduce greenhouse gas emissions from other countries.
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In Judge Tatel’s view,the “‘substantial probability,’” id., at 66, that projected rises in sea level would lead to serious loss of coastal property was a “far cry” from the kind of generalized harm insufficient to ground Article III jurisdiction. Id., at 65. He found that petitioners’ affidavits more than adequately supported the conclusion that EPA’s failure to curb greenhouse gas emissions contributed to the sea level changesthat threatened Massachusetts’ coastal property. Ibid. As to redressability, he observed that one of petitioners’ experts, a former EPA climatologist, stated that “‘[a]chievable reductions in emissions of CO2 and other [greenhouse gases] from U. S. motor vehicles would . . . delay and moderate many of the adverse impacts of global warming.’”
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EPA maintains that because greenhouse gas emissions inflict widespread harm, the doctrine of standing presentsan insuperable jurisdictional obstacle. We do not agree.At bottom, “the gist of the question of standing” is whetherpetitioners have “such a personal stake in the outcome ofthe controversy as to assure that concrete adverseness which sharpens the presentation of issues upon which the court so largely depends for illumination.”
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We stress here, as did Judge Tatelbelow, the special position and interest of Massachusetts.It is of considerable relevance that the party seeking review here is a sovereign State and not, as it was in Lujan, a private individual.
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The harms associated with climate change are seriousand well recognized. Indeed, the NRC Report itself—which EPA regards as an “objective and independentassessment of the relevant science,” 68 Fed. Reg. 52930—identifies a number of environmental changes that havealready inflicted significant harms, including “the globalretreat of mountain glaciers, reduction in snow-coverextent, the earlier spring melting of rivers and lakes, [and]the accelerated rate of rise of sea levels during the 20th century relative to the past few thousand years . . . .” NRC Report 16.
Petitioners allege that this only hints at the environmental damage yet to come. According to the climate scientist Michael MacCracken, “qualified scientific expertsinvolved in climate change research” have reached a“strong consensus” that global warming threatens (among other things) a precipitate rise in sea levels by the end of the century, MacCracken Decl. ¶15, Stdg. App. 207, “severe and irreversible changes to natural ecosystems,” id., ¶5(d), at 209, a “significant reduction in water storage inwinter snowpack in mountainous regions with direct andimportant economic consequences,” ibid., and an increase in the spread of disease, id., ¶28, at 218–219. He also observes that rising ocean temperatures may contribute to the ferocity of hurricanes. Id., ¶¶23–25, at 216–217.18
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EPA does not dispute the existence of a causal connection between man-made greenhouse gas emissions and global warming.
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EPA overstates its case. Its argument rests on the erroneous assumption that a small incremental step, because it is incremental, can never be attacked in a federal judicial forum. Yet accepting that premise woulddoom most challenges to regulatory action. Agencies, like legislatures, do not generally resolve massive problems inone fell regulatory swoop.
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While it may be true that regulating motor-vehicle emissions will not by itself reverse global warming, it by nomeans follows that we lack jurisdiction to decide whetherEPA has a duty to take steps to slow or reduce it.
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We moreover attach considerable significance to EPA’s“agree[ment] with the President that ‘we must address the issue of global climate change,’” ... and to EPA’s ardent support for various voluntary emission-reduction programs, 68 Fed. Reg. 52932. As Judge Tatel observed in dissent below, “EPA would presumably not bother with such efforts if itthought emissions reductions would have no discernable impact on future global warming.”
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unlike EPA, we have no difficulty reconciling Congress’ various efforts to promote interagency collaboration and research to better understand climate change28 with the agency’s pre-existing mandate to regulate “any air pollutant” that may endanger the public welfare.
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The alternative basis for EPA’s decision—that even if it does have statutory authority to regulate greenhousegases, it would be unwise to do so at this time—rests on reasoning divorced from the statutory text....that judgment must relate to whether an air pollutant“cause[s], or contribute[s] to, air pollution which mayreasonably be anticipated to endanger public health or welfare,”....Under the clear terms of the Clean Air Act, EPA can avoid taking further action only if itdetermines that greenhouse gases do not contribute toclimate change or if it provides some reasonable explanation as to why it cannot or will not exercise its discretionto determine whether they do.
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while the President hasbroad authority in foreign affairs, that authority does not extend to the refusal to execute domestic laws.
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Nor can EPA avoid its statutory obligation by noting theuncertainty surrounding various features of climate changeand concluding that it would therefore be better not toregulate at this time. See 68 Fed. Reg. 52930–52931. If the scientific uncertainty is so profound that it precludes EPA from making a reasoned judgment as to whether greenhouse gases contribute to global warming, EPA must say so.

(Roberts dissent)

Global warming may be a “crisis,” even “the most pressing environmental problem of our time.” Pet. for Cert. 26, 22. Indeed, it may ultimately affect nearly everyone on the planet in some potentially adverse way, and it may bethat governments have done too little to address it.
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I would reject these challenges as nonjusticiable. Such a conclusion involves no judgment on whether global warming exists, what causes it, or the extent of the problem.
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The very concept of global warming seems inconsistent with this particularization requirement. Global warmingis a phenomenon “harmful to humanity at large,”
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In light of the bit-part domestic new motor vehicle greenhouse gas emissions have played in whatpetitioners describe as a 150-year global phenomenon, and the myriad additional factors bearing on petitioners’ alleged injury—the loss of Massachusetts coastal land—theconnection is far too speculative to establish causation.

Scalia's dissent said nothing interesting.