than of foreseeability, though foreseeability is still important. See Arcadian Corp., 189 F.3d 305 at
315â“16 (citing Kuzmicz v. Ivy Hill Park Apartments, Inc., 688 A.2d 1018, 1020 (N.J. 1997)).
See supra note 28.
See, e.g., Morris v. Chrysler Corp., 303 N.W.2d 500, 502â“03 (Neb. 1981).
Cf. In re Methyl Tertiary Butyl Ether (âMTBEâ) Prod. Liab. Litig., 175 F. Supp. 2d 593, 625â“26
Id. at 625 (citing McLaughlin v. Mine Safety Appliances Co., 181 N.E.2d 430, 433 (N.Y. 1962)).
White v. Smith & Wesson, 97 F. Supp. 2d 816, 828â“29 (N.D. Ohio 2000) (citing Gedeon v. E. Ohio
Gas Co., 190 N.E. 924, 926 (Ohio 1934)).
See supra Section 2.2.
Some states have established statutory presumptions that a product is not defective if its design
conforms to the âstate of the art.â Oâ™Reilly & Cody, supra note 42, at 72.
Tort-Based Climate Litigation 205
the forefront of technology; the term sometimes refers to economic feasibility, the
existence of generally recognized industry practices, or the existence of industry or
government design standards.82
As previously noted, climate change plaintiffs might have trouble showing that
all alternative designs were economically feasible.83 The government standards in
Title II of the Clean Air Act (CAA)84 might also bolster industry claims of meeting
the state of the art in automotive emissions and fuel efď¬ciency, though foreign
manufacturers adopted some basic technologies well before U.S. manufacturers,
resulting in marked differences in fuel efď¬ciency.85 This fact might help defeat any
claims of an âindustry practice.â Furthermore, even if no manufacturer adopts or
considers alternative designs, a plaintiff still can introduce expert testimony to show
that, as a practical matter, manufacturers could have adopted a reasonable alternative
design.86 For instance, climate change plaintiffs might be able to show the existence
of such an alternative design for the current production of fuel-inefď¬cient SUVs.
The third step in climate plaintiffsâ™ negligence claim is to establish proximate
causation. Section 4 addresses this issue.87 Defendants in a negligence suit, though,
can offer evidence of plaintiffsâ™ conduct to defeat or mitigate a ď¬nding that defendants
were the proximate cause of plaintiffsâ™ injuries. These defenses fall into two general
categories: (1) contributory negligence or comparative fault; and (2) assumption of
risk.88 Contributory negligence means that plaintiffs were negligent in a way that
contributed to their injuries. Historically, and still in a few jurisdictions, contributory
negligence defeats any liability for defendants.89 Most jurisdictions, however, utilize
comparative fault, in which courts reduce the defendantsâ™ liability proportionate to
the plaintiffsâ™ degree of fault.90 âAssumption of riskâ means that courts bar plaintiffs
from recovery because plaintiffs knew of the productâ™s danger but nevertheless
unreasonably proceeded to use it.91
Id. at 154. Courts may reject a scientiď¬cally sound alternative design because its expense would prevent
it from being commercially viable or because government or formal private standards could be said
to express the state of the art of safe design. Id.; see also Restatement (Third) of Torts: Products
Liability Â§ 2 cmt. d (1998).
See supra notes 62â“66 and accompanying text.
42 U.S.C. Â§Â§ 7521â“7590 (2001).
See, e.g., Doyle, supra note 47, at 253 (noting difference in Toyota and Ford fuel efď¬ciencies in 1988,
largely due to Toyotaâ™s adoption of multivalve engines); id. at 255, 261 (noting high miles per gallon
(MPG) achieved by French Citroens AX-10 and by Honda Civics sold in America in 1990, compared
to declining MPGs of U.S.-manufactured cars); see also supra note 64.
See Restatement (Third) of Torts: Products Liability Â§ 2 cmt. d (1998).
See infra Section 4.2.
Defendants can also claim contributory negligence, comparative fault, and assumption of risk in strict
liability cases, but only if plaintiffâ™s conduct is voluntary and unreasonable. See Borel v. Fibreboard
Paper Prods. Corp., 493 F.2d 1076, 1097â“98 (5th Cir. 1973), cert. denied, 419 U.S. 869 (1974); see also
Oâ™Reilly & Cody, supra note 42, at 164.
Oâ™Reilly & Cody, supra note 42, at 28.
Id. About two-thirds of states have comparative fault legislation or decisions. Id. at 164.
Restatement (Second) of Torts Â§ 402A cmt. n (1965). Cigarette manufacturers often used this
defense in tobacco lawsuits brought by smokers.
David A. Grossman
At ď¬rst glance, defendantsâ™ defenses appear to have merit in a climate suit. Defen-
dants could argue that plaintiffs have been well aware that products like cars produce
emissions that aggravate climate change, yet plaintiffs, their agents, and their citizens
have continued to use those products with that knowledge. Climate change plaintiffs
have strong rebuttals to these defenses, however. First, citizensâ™ awareness of the risks
posed by use of fossil fuels is debatable, although such awareness has recently been
on the rise.92 Second, even assuming that citizens are aware of the risks, it would be
difď¬cult for defendants to show that plaintiffs acted unreasonably, especially given
the few practical alternatives to using these manufacturersâ™ products.
All things considered, therefore, climate change plaintiffsâ™ strongest products lia-
bility claim would appear to be a design defect suit. However, recognition of man-
ufacturersâ™ duties to climate change victims outside of their capacity as users or
consumers of products that emit carbon dioxide is by no means certain, and poten-
tial defendants might be able to present strong âstate of the artâ defenses. While a
products liability claim might be viable, therefore, these caveats suggest that it is a
much weaker claim than public nuisance.
3. JURISDICTIONAL HURDLES
Climate plaintiffs seeking to press a tort claim â“ whether public nuisance, products
liability, or some other tort â“ cannot, of course, go right to the merits of the case. They
must ď¬rst clear various jurisdictional hurdles. The principal ones in this context are
standing, preemption, and justiciability.
As stated by the Supreme Court, âto satisfy Article IIIâ™s standing requirements, a
plaintiff must show (1) it has suffered an injury in fact that is (a) concrete and
particularized and (b) actual or imminent, not conjectural or hypothetical; (2) the
injury is fairly traceable to the challenged action of the defendant; and (3) it is likely,
as opposed to merely speculative, that the injury will be redressed by a favorable
See supra note 34; see also Penalver, supra note 4, at 577 n.71 (âThe public campaigns carried
out by fossil fuel companies have made it very difď¬cult for the average consumer to accurately
weigh the risks involved in continued use of fossil fuels.â). For information on recently increasing
awareness, see, e.g., Zogby International/National Wildlife Federation Survey, Aug. 11â“15, 2006, at
http://www.zogby.com/wildlife/NWFď¬nalreport8â“17-06.htm (âThree-fourths of likely voters (74%) are
more convinced from events over the past two years that global warming is happening, with two in
ď¬ve (40%) saying they are much more convinced.â).
Friends of the Earth v. Laidlaw Envtl. Servs. (TOC), 528 U.S. 167, 180â“81 (2000) (citing Lujan v.
Defenders of Wildlife, 504 U.S. 555, 560â“61 (1992)). The general rule is that a plaintiff must show a
particularized harm; if all citizens are affected in the same way, the assumption is that they should go
to their legislature. See, e.g., Fla. Audubon Socâ™y v. Bentsen, 94 F.3d 658, 667 n.4 (D.C. Cir. 1996)
(â[T]he plaintiff must show that he is not simply injured as is everyone else, lest the injury be too
general for court action, and suited instead for political redress.â).
Tort-Based Climate Litigation 207
The Supreme Court recently addressed many of these issues in Massachusetts v.
EPA, in which a group of states, local governments, and nongovernmental organi-
zations sued the Environmental Protection Agency over its rejection of a petition
to regulate greenhouse gas emissions from new motor vehicles under the Clean
Air Act.94 Ruling on the standing of state petitioner Massachusetts, and recognizing
both the stateâ™s âquasi-sovereign . . . interest independent of and behind the titles of
its citizensâ and the fact that the state itself âowns a great deal of the â˜territory alleged
to be affected,â™â the Court ď¬rst noted that the state is âentitled to special solicitude
in our standing analysis.â95 This âspecial solicitudeâ might in fact be even greater in
a public nuisance case. The underlying basis for public nuisance is âto protect the
public from lawful and even productive activities that are substantially incompatible
with the publicâ™s common rights. Public nuisance is the only tort designed and
equipped to protect the public from activities or conduct that is incompatible with
public health, safety, or peace.â96 Given this underlying public basis, the typical
plaintiff in a public nuisance action is a governmental entity or ofď¬cial seeking to
protect the public, such as mayors and other city executive ofď¬cials, county executive
ofď¬cials, governors, and state attorneys general.97
In determining the ď¬rst requirement of standing, the Court in Massachusetts v.
EPA noted that â[t]he harms associated with climate change are serious and well
recognized,â including âreduction in snow-cover extentâ and âthe accelerated rate of
rise of sea levels,â and that the fact that âthese climate-change risks are â˜widely sharedâ™
does not minimize Massachusettsâ™ interest in the outcome of this litigation.â98 The
549 U.S. 497 (2007).
Id. at 518â“20 (ď¬rst quotation quoting Georgia v. Tenn. Copper, 206 U.S. 230, 237 (1907)).
Kairys, supra note 32, at 1178.
See id. at 1175, 1177 n.9, 1181; see also id. at 1176 (âA public nuisance claim is the vehicle provided by
civil law for executive-branch ofď¬cials to seek immediate relief to stop and remedy conduct that is
endangering the public.â); State v. Lead Indus. Assâ™n, No. 99-5226, 2001 R.I. Super. LEXIS 37, at â—â— 6â“7
(R.I. Super. Apr. 2, 2001). But cf. Ganim v. Smith & Wesson Corp., 780 A.2d 98, 131â“33 (Conn. 2001)
(ď¬nding city of Bridgeport and its mayor not to have standing in public nuisance handgun suit because
harms alleged were derivative and remote). Citizens can also bring public nuisance actions, although
the Restatement limited the class of private plaintiffs who could recover damages to those who had
âsuffered harm of a kind different from that suffered by other members of the public exercising the
right common to the general public that was the subject of the interference.â Restatement (Second)
of Torts Â§ 821C(1) (1979). Without such a particularized injury, victims generally must seek a remedy
through the public authorities. See Connerty v. Metro. Dist. Commâ™n, 495 N.E.2d 840, 845 (Mass.
1986). But see Akau v. Olohana Corp., 652 P.2d 1130, 1134 (Haw. 1982) (holding that member of the
public without special injury has standing to sue to enforce rights of public if he or she can show injury-
in-fact and satisfy the court that concerns of multiplicity of suits will be satisď¬ed by any means, including
class action). Even if they could establish such particularized injury, however, citizen plaintiffs
in a climate change suit would face great difď¬culties in showing causation. See infra Section 4.1.
549 U.S. at 521â“22. See also Lujan v. Defenders of Wildlife, 504 U.S. 555, 581 (1992) (Kennedy, J.,
concurring in part and concurring in the judgment) (âWhile it does not matter how many persons
have been injured by the challenged action, the party bringing suit must show that the action injures
him in a concrete and personal way.â); Warth v. Seldin, 422 U.S. 490, 501 (1975) (holding that plaintiff
may be able to satisfy Article III standing requirements âeven if it is an injury shared by a large class
of other possible litigants.â).
David A. Grossman
Court also found particularized injury in the fact that ârising seas have already begun
to swallow Massachusettsâ™ coastal land,â which affects the state âin its capacity as a
landowner.â99 Other states and governmental parties suing for similar climate harms
should likewise be able to establish injury in fact.
The second standing requirement is traceability. In Massachusetts v. EPA, the
Court noted that because EPA did not dispute the causal connection between
man-made greenhouse gas emissions and global warming, the agencyâ™s ârefusal
to regulate such emissions â˜contributesâ™ to Massachusettsâ™ injuries.â100 Despite the
fact that EPA claimed its decision was an insigniď¬cant contributor to the stateâ™s
injuries, the Court noted that âU.S. motor-vehicle emissions make a meaningful
contribution to greenhouse gas concentrations and hence, according to petitioners,
to global warming.â101 Similarly, as explained in more detail in Section 4, plaintiffs
in a climate change tort suit could likely trace their harms in part to the emissions
contributed by defendants.102
The third prong requires plaintiffs to show that a favorable judicial decision would
redress their harms. Clearly, an award of damages could compensate climate plain-
tiffs for present harms and expenses incurred. If plaintiffs seek injunctive relief to
enjoin defendantsâ™ emissions,103 the issue seems more complicated, since defen-
dantsâ™ reductions would still leave numerous other emitters and a large amount of
greenhouse gases already in the atmosphere. Defendants could argue, therefore,
that plaintiffsâ™ harms will occur regardless of whether they reduce their emissions.
The Supreme Court essentially rejected this argument, however, in Massachusetts
v. EPA. The Court acknowledged that âregulating motor-vehicle emissions will not
by itself reverse global warming,â but noted that this did not mean that it âlack[ed]
jurisdiction to decide whether EPA has a duty to take steps to slow or reduce it.â104
Despite the fact that increases from other emission sources would dwarf the amount
of reductions achieved, a âreduction in domestic emissions would slow the pace
of global emissions increases, no matter what happens elsewhere.â105 In sum, the
Court held that petitioners had standing because â[t]he risk of catastrophic harm,
though remote, is nevertheless real. That risk would be reduced to some extent if
petitioners received the relief they seek.â106
After Massachusetts v. EPA, the ability of plaintiffs in a climate tort case to establish
standing therefore appears greatly enhanced. This is particularly so for sovereign
climate plaintiffs, who are entitled to âspecial solicitude,â but even climate plaintiffs
U.S. at 522.
101 Id. at 525.
102 See infra Section 4.
103 In Laidlaw, the Supreme Court explained that the plaintiff must demonstrate standing for each form
of relief sought. 528 U.S. at 185.
104 549 U.S. at 525 (emphasis in original).
105 Id. at 526.
Tort-Based Climate Litigation 209
that are not sovereigns seem to be on stronger footing given the Courtâ™s Article III
Climate plaintiffs seeking to press a federal or state common law tort claim such as
public nuisance may have to address the issue of preemption.107 The preemption
standards and analyses for federal common law and state common law are different,
since â[f]ederal courts, unlike state courts, are not general common-law courts and
do not possess a general power to develop and apply their own rules of decision.â108
3.2.1. Preemption of Federal Common Law Claims
The Supreme Court has recognized essentially two limited instances in which
federal common law may exist: (1) where Congress has given the courts power
to develop substantive law, and (2) where a federal rule of decision is needed to
protect âuniquely federal interests.â109 If either instance applies, the Court will
allow plaintiffs to invoke federal common law, unless displaced by a federal statute.
The ď¬rst instance does not seem to apply in the climate change context, as Congress
clearly has not given courts explicit authority to develop substantive law in the area
of climate change harms. The second instance, however, could be relevant.
âUniquely federal interestsâ exist only in particular narrow areas, such as disputes
concerning âthe rights and obligations of the United Statesâ and âinterstate and
international disputes implicating the conď¬‚icting rights of States or our relations
with foreign nations.â110 The Court recognizes federal common law in such dis-
putes because âour federal system does not permit the controversy to be resolved
under state law, either because the authority and duties of the United States as
sovereign are intimately involved or because the interstate or international nature
of the controversy makes it inappropriate for state law to control.â111 In situations
in which a state (as a state or under parens patriae) is suing sources outside of its
own territory because they are causing air pollution within the state, the Court
thus has been willing to recognize a federal common law tort claim.112 Analogizing
107 Although many of the cases below deal with nuisance claims, the same ordinary preemption principles
and analysis apply to products liability suits. See, e.g., Geier v. Am. Honda Motor Co., 529 U.S. 861
(2000); Nathan Kimmel, Inc. v. DowElanco, 275 F.3d 1199 (9th Cir. 2002); Choate v. Champion
Home Builders Co., 222 F.3d 788 (10th Cir. 2000).
108 City of Milwaukee v. Illinois, 451 U.S. 304, 312 (1981) (Milwaukee II).
109 Texas Indus. v. Radcliff Materials, Inc., 451 U.S. 630, 640 (1981).
110 Id. at 641.
112 See Natâ™l Audubon Socâ™y v. Depâ™t of Water, 869 F.2d 1196, 1205 (9th Cir. 1988) (holding dispute at issue
to be solely domestic and thus not properly asserted under the federal common law developed under
Illinois v. Milwaukee, 406 U.S. 91, 107 n.9 (1972) (Milwaukee I)); Georgia v. Tenn. Copper Co., 206 U.S.
230, 237 (1907); and Missouri v. Illinois, 200 U.S. 496, 520â“21 (1906)); see also Ouellette v. Intâ™l Paper
David A. Grossman
this idea to the climate context, states could bring suits based on federal com-
mon law if they would be suing sources outside their territory for internal harms
Federal statutes or regulations will preempt federal common law if they âfully
authorizedâ defendantsâ™ behavior, established a âcomprehensive set of legislative acts
or administrative regulations governing the details of a particular kind of conduct,â
or âspoke directly to a questionâ at issue in the dispute.113 The question of whether
a federal statute preempts federal common law âinvolves an assessment of the scope
of the legislation and whether the scheme established by Congress addresses the
problem formerly governed by federal common law.â114
The Courtâ™s 2007 decision in Massachusetts v. EPA raises the possibility that
the Clean Air Act (CAA) might preempt a federal common law tort claim on
climate change, since the Court has now held that the EPA has authority to regulate
greenhouse gases from new motor vehicles as air pollutants under the CAA,115 and
it is possible that this reasoning could extend to stationary sources of emissions
(e.g., power plants) as well.116 Although President Obamaâ™s EPA is likely to develop
regulations shortly to limit greenhouse gas emissions from new mobile sources,
there are still no actual regulations yet, which means federal common law likely still
In Illinois v. City of Milwaukee (Milwaukee I), the Court allowed a federal com-
mon law nuisance suit on interstate water pollution to proceed, ď¬nding that the
water quality legislation in existence at the time did not contain the remedy sought
by Illinois and noting that â[u]ntil the ď¬eld has been made the subject of compre-
hensive legislation or authorized administrative standards, only a federal common
law basis can provide an adequate means for dealing with such claims as alleged
federal rights.â117 The Court observed that â[i]t may happen that new federal laws
and new federal regulations may in time pre-empt the ď¬eld of federal common
law of nuisance. But until that comes to pass, federal courts will be empowered to
appraise the equities of the suits alleging creation of a public nuisance by water
Co., 666 F. Supp. 58, 61 (D. Vt. 1987) (âThe Milwaukee I, Wyandotte, and Milwaukee II decisions
are noncontrolling in this case because those decisions involved states which, when acting as states,
ď¬led actions under the Supreme Courtâ™s original jurisdiction to resort to the â˜necessary expedientâ™ of
federal common law to obtain relief from interstate pollution. Because federalism concerns precluded
the state sovereigns from resorting to state law claims, the Court applied federal common law in the
Milwaukee dispute because it was â˜concerned in that case that Illinois did not have any forum in
which to protect its interests unless federal common law were created.â™â).
113 Restatement (Second) of Torts Â§ 821B cmt. f (1979); Milwaukee II, 451 U.S. at 315, 319 n.14.
114 Milwaukee II, 451 U.S. at 315 n.8.
115 127 S. Ct. at 1459â“62.
116 See, e.g., Robert Meltz, Legislative Attorney, American Law Division, Congressional Research Service,
The Supreme Courtâ™s Climate Change Decision: Massachusetts v. EPA, CRS Report for Congress
RS22665, May 18, 2007, 6 (âThe stationary-source provisions of the CAA [42 U.S.C. Â§ 7408(a)(1)-(2)]
use terms similar to that of Section 202 â“ in particular, â˜air pollutant,â™ â˜in his judgment,â™ and â˜may
reasonably be anticipated to endanger public health and welfare.â™â).
117 406 U.S. 91, 103, 107 n.9 (1972) (citation omitted).
Tort-Based Climate Litigation 211
pollution.â118 Such new laws came to pass with amendments creating the compre-
hensive Clean Water Act, so when the Court revisited the issue in Milwaukee v.
Illinois (Milwaukee II), the Court found that Congress had supplanted federal com-
mon law when it âoccupied the ď¬eld through the establishment of a comprehensive
regulatory program supervised by an expert administrative agency,â representing
âan all-encompassing program of water pollution regulation.â119 It therefore seems
that federal common law is displaced only when there is a comprehensive set of
regulations in place that cover the particular issue.
The Court also emphasized in County of Oneida v. Oneida Indian Nation of
New York State that âfederal common law is used as a â˜necessary expedientâ™ when
Congress has not â˜spoken to a particular issue.â™â120 In Oneida, the Court found
that the Oneida Indian Tribes had a federal common law cause of action for
the occupation and use by counties of aboriginal tribal land, since the Nonin-
tercourse Act of 1793 âdoes not speak directly to the question of remedies for unlaw-
ful conveyances of Indian land.â121 In other words, because the law did not pro-
vide a remedy for the particular claim advanced, federal common law remained
In the climate tort context, there remains no comprehensive federal regulatory
scheme akin to the Clean Water Act that governs greenhouse gas emissions,122 nor is
any regulation in place that provides a remedy to states and other plaintiffs harmed
by greenhouse gas emissions. Massachusetts v. EPA says the EPA has authority to
regulate such emissions, but it does not require such regulation,123 no regulation
currently exists, and no regulations may exist for a while. Although the existence of
EPA authority to regulate greenhouse gases may lead some to suggest that federal
U.S. 304, 317â“19 (1981).
120 470 U.S. 226, 237 (1985) (emphasis added in original to quote from Milwaukee II, 451 U.S. at 313â“14).
122 The CAA is not as comprehensive as the Clean Water Act (CWA). While the CWA prohibits every
point source discharge into navigable water without a permit, the CAA prohibits only unpermitted
emissions of certain listed pollutants that have been found to threaten the air-quality standards pro-
mulgated by the EPA. New England Legal Found. v. Costle, 666 F.2d 30, 32 n.2 (2d Cir. 1981); Natâ™l
Audubon Socâ™y v. Depâ™t of Water, 869 F.2d 1196, 1212â“14 (9th Cir. 1988) (Reinhardt, J., dissenting).
Two district courts have found the CAA to preempt federal common law in air pollution cases. In
United States v. Kin-Buc, Inc., 532 F. Supp. 699, 701â“02 (D.N.J. 1982), the court acknowledged the
difference in comprehensiveness between the CWA and CAA but nonetheless found that Congress
had occupied the ď¬eld. In Reeger v. Mill Serv., Inc., 593 F. Supp. 360, 363 (W.D. Pa. 1984), the court,
without comparing comprehensiveness, also found that the CAAâ™s regulatory scheme was similar to
the CWAâ™s and thus applied âthe same principle of preemption.â Higher courts have explicitly not
reached the issue â“ Natâ™l Audubon Socâ™y v. Depâ™t. of Water, 869 F.2d 1196, 1205 (9th Cir. 1988); New
England Legal Found., 666 F.2d at 32, 32 n.2 â“ and at least one Ninth Circuit judge would have ruled
differently (Natâ™l Audubon Socâ™y, 869 F.2d at 1212â“14 (Reinhardt, J., dissenting)).
123 127 S. Ct. at 1463. See also Robert Meltz, Legislative Attorney, American Law Division, Congressional
Research Service, The Supreme Courtâ™s Climate Change Decision: Massachusetts v. EPA, CRS Report
for Congress RS22665, May 18, 2007, 1 (âThe decision does not compel EPA to regulate greenhouse
gas (GHG) emissions from new motor vehicles, but it does limit the range of options available to the
agency that would justify not doing so.â).
David A. Grossman
common law is preempted,124 it seems likely that climate plaintiffs will be able to
pursue federal common law tort claims until regulations exist that comprehensively
govern the ď¬eld or that provide a remedy for states harmed by greenhouse gas
3.2.2. Preemption of State Common Law Claims
Unlike federal courts, state courts are general common law courts.125 As such, federal
law preempts state law (including state common law) only when (1) it is the âclear and
manifest purpose of Congress,â126 (2) the federal law is âsufď¬ciently comprehensive
to make reasonable the inference that Congress â˜left no roomâ™ for supplementary
state regulation,â127 or (3) a state law âactually conď¬‚icts with a valid federal statuteâ128
in that it âstands as an obstacle to the accomplishment and execution of the full
purposes and objectives of Congress.â129
The Supreme Court found in International Paper Co. v. Ouellette that the Clean
Water Act preempted the nuisance law of a state affected by water pollution, since it
stood as an obstacle to the Actâ™s comprehensive scheme regulating every point source
discharge.130 The Court, however, found that ânothing in the Act bars aggrieved
individuals from bringing a nuisance claim pursuant to the law of the source State.â131
On remand, the district court found that âthe same concerns that led the Ouellette
Court to require application of the source stateâ™s law in interstate water disputes
are equally applicable to [the CAA and to private party] plaintiffsâ™ air claims.â132
Similarly, it is likely that the CAA would not preempt a climate change tort claim
based on the common law of a source state â“ for instance, one in which many
coal-ď¬red electric utilities reside.
It is possible, however, that the CAA might preempt state common law claims
against automobile or gasoline manufacturers, since Congress did âspeak directly
toâ the issue of automobile emissions and fuels. Under section 209 of the CAA,
â[n]o State or any political subdivision thereof shall adopt or attempt to enforce
any standard relating to the control of emissions from new motor vehicles or new
124 Cf. Mattoon v. City of Pittsď¬eld, 980 F.2d 1, 5 (1st Cir. 1992) (âThe comprehensiveness of the legislative
grant is not diminished, nor is the congressional intent to occupy the ď¬eld rendered unclear, merely
by reason of the regulatory agencyâ™s discretionary decision to exercise less than the total spectrum
of regulatory power with which it was invested.â). Mattoon seems contrary to the Supreme Courtâ™s
emphasis in Oneida that a regulatory scheme must speak to the âparticularâ issue in order to displace
federal common law.
125 Milwaukee II, 451 U.S. at 312.
126 Rice v. Santa Fe Elevator Corp., 331 U.S. 218, 230 (1947).
127 Hillsborough County v. Automated Med. Lab., Inc., 471 U.S. 707, 713 (1985).
128 Ray v. Atlantic Richď¬eld Co., 435 U.S. 151, 158 (1978).
129 Hillsborough County, 471 U.S. at 713 (quoting Hines v. Davidowitz, 312 U.S. 52, 67 (1941)).
130 479 U.S. 481, 494â“97 (1987).
131 Id. at 497 (emphasis in original).
132 Ouellette v. Intâ™l. Paper Co., 666 F. Supp. 58, 62 (D. Vt. 1987).
Tort-Based Climate Litigation 213
motor vehicle engines.â133 The Supreme Court has noted that âCongress has largely
pre-empted the ď¬eld with regard to â˜emissions from new motor vehicles,â™ and motor
vehicle fuels and fuel additives.â134
In sum, it seems likely that the CAA would not preempt federal common law
claims, at least until comprehensive regulations are in place (and perhaps even
then, if the regulations do not provide a remedy for harms), and would not preempt
claims based on a source stateâ™s common law, so long as the emissions at issue in the
state common law claim are not from motor vehicles.
One ď¬nal jurisdictional hurdle to consider is justiciability, which was the basis of
dismissal in both Connecticut v. AEP and California v. GM. In Connecticut, the
district court dismissed the case â[b]ecause resolution of the issues presented here
requires identiď¬cation and balancing of economic, environmental, foreign policy,
and national security interests, [so] â˜an initial policy determination of a kind clearly
for non-judicial discretionâ™ is required.â135 The court accordingly concluded that
âthese actions present non-justiciable political questions that are consigned to the
political branches, not the Judiciary.â136 Similarly, in California, the court wrote
that â[j]ust as in AEP, the adjudication of Plaintiffâ™s claim would require the Court
to balance the competing interests of reducing global warming emissions and the
interests of advancing and preserving economic and industrial development. The
balancing of those competing interests is the type of initial policy determination to
be made by the political branches, and not this Court. . . . [T]he Court ď¬nds that the
claim presents a non-justiciable political question.â137
The political question doctrine âis designed to restrain the Judiciary from inap-
propriate interference in the business of the other branches of Government.â138 In
Baker v. Carr, the Supreme Court explained that:
Prominent on the surface of any case held to involve a political question is found
a textually demonstrable constitutional commitment of the issue to a coordinate
political department; or a lack of judicially discoverable and manageable standards
for resolving it; or the impossibility of deciding without an initial policy determi-
nation of a kind clearly for nonjudicial discretion; or the impossibility of a courtâ™s
U.S.C. Â§ 7543(a) (2001); see also id. Â§ 7545(c)(4)(A) (fuels). Section 209(b) of the Act contains an
exception for California, id. Â§ 7543(b), and other states have the option of adopting the California
emission standards, id. Â§ 7507.
134 Washington v. Gen. Motors Corp., 406 U.S. 109, 114 (1972) (citations omitted); see also Am. Auto.
Mfrs. Assâ™n v. Cahill, 152 F.3d 196, 198 (2d Cir. 1998) (explaining exception for California and for states
opting in to California standards).
135 406 F. Supp. 2d 265, 274 (2005).
137 No. C06â“05755, 2007 U.S. Dist. LEXIS 68547, at â—â— 23â“24, â— 48 (N.D. Cal. Sept. 17, 2007) (citation
138 United States v. Munoz-Flores, 495 U.S. 385, 394 (1990).
David A. Grossman
undertaking independent resolution without expressing lack of the respect due coor-
dinate branches of government; or an unusual need for unquestioning adherence
to a political decision already made; or the potentiality of embarrassment from mul-
tifarious pronouncements by various departments on one question. Unless one of
these formulations is inextricable from the case at bar, there should be no dismissal
for non-justiciability on the ground of a political questionâ™s presence.139
Most of the Baker factors do not seem particularly relevant to the climate tort con-
text. For instance, there appears to be no âtextually demonstrable constitutional com-
mitmentâ of climate change abatement or damages to Congress or the Executive.140
Similarly, it seems that courts have extensive experience with nuisance cases seek-
ing damages from and/or abatement of pollution by the defendants before them,141
suggesting both that there could be standards for resolving climate tort suits and that
courts would not be showing disrespect to other branches by resolving an interstate
nuisance dispute.142 Additionally, there does not appear to be a coherent national
political decision already made about greenhouse gas abatement and damages,143
and court action concerning particular defendants and plaintiffs would not âinap-
propriate[ly] interfereâ with the other branches of government continuing their
own climate change efforts (Congress can, in fact, override through legislation any
result from a federal common law court decision).
As noted, the district courts in Connecticut v. AEP and California v. GM both cited
the third factor as the most relevant, concerning âan initial policy determination.â144
On the one hand, asking a court to mandate greenhouse gas emission reductions
from power plant defendants could seem like a court dictating aspects of energy or
climate policy, but on the other hand, courts are well equipped to determine whether
pollution from out-of-state actors is harming a state and so must be abated.145 For
U.S. 186, 217 (1962).
see California v. Gen. Motors Corp., 2007 U.S. Dist. LEXIS 68547, at â— 43 (â[T]he Court ď¬nds
that Plaintiffâ™s federal common law global warming nuisance tort would have an inextricable effect on
interstate commerce and foreign policy â“ issues constitutionally committed to the political branches
141 See, e.g., Georgia v. Tenn. Copper, 206 U.S. 230 (1907). See also Weinberger v. Romero-Barcelo, 456
U.S. 305, 314 n.7 (noting that the objective of the Clean Water Act is âin some respects similar to that
sought in nuisance suits, where courts have fully exercised their equitable discretion and ingenuity
in ordering remediesâ); Reserve Mining Co. v. EPA, 514 F.2d 492, 535â“42 (8th Cir. 1975) (describing
142 But see California v. Gen. Motors Corp., 2007 U.S. Dist. LEXIS 68547, at â— 46 (â[T]he cases cited
by Plaintiff do not provide the Court with legal framework or applicable standards upon which to
allocate fault or damages, if any, in this case. The Court is left without guidance in determining
what is an unreasonable contribution to the sum of carbon dioxide in the Earthâ™s atmosphere, or
in determining who should bear the costs associated with the global climate change that admittedly
result from multiple sources around the globe.â).
143 This is particularly evident given the current debates in Congress about whether and how to enact a
greenhouse gas abatement scheme.
144 California v. Gen. Motors Corp., 2007 U.S. Dist. LEXIS 68547, at â— 17; Connecticut v. Am. Elec.
Power Co., 406 F. Supp. 2d 265, 272 (S.D.N.Y. 2005).
145 Massachusetts v. EPA seems to have settled that even incremental abatements in greenhouse gas
emissions would partially redress plaintiff harms. See supra notes 104â“106 and accompanying text.
Tort-Based Climate Litigation 215
instance, the Court has previously afď¬rmed the justiciability of interstate nuisance
actions, noting that â[w]hile we have refused to entertain, for example, original
actions that seek to embroil this tribunal in â˜political questions,â™ this Court has
often adjudicated controversies between States and between a State and citizens of
another State seeking to abate a nuisance that exists in one State yet produces noxious
consequences in another.â146 Furthermore, this issue seems somewhat clearer when
suits involve damages claims instead of injunctive relief, as a court need make no
policy judgments about issues such as abatement in order to determine that a state
has been harmed by climate change, that defendants are substantial contributors to
climate change, and that the state is entitled to damages.147
In sum, it seems that the political question doctrine would be inapplicable to
many climate tort claims, although both district courts to have ruled on climate
nuisance cases have found otherwise. However, it is worth remembering that the
mere fact that âthese cases present issues that arise in a politically charged context
does not transform them into cases involving nonjusticiable political questions.â148
4. CAUSATION AND SUBSTANTIALITY
Causation in any climate change tort suit will be a complicated issue, as plaintiffs
must show that their harms are traceable to defendantsâ™ actions. This section analyzes
the issue of causation in the climate change context and explains why causation is
easier to establish for certain types of defendants.
4.1. Generic and Speciď¬c Causation
In many toxic tort cases, as in a climate case, simple causal chains do not exist.
Instead, plaintiffs must rely on more statistical or probabilistic means. In mass expo-
sure cases such as Agent Orange, for instance, plaintiffs often had to rely on epidemi-
ological studies to demonstrate the association between exposure to a substance and
deleterious health effects.149 Such studies attempt to establish generic causation â“
whether it can be said that the substance, as a general proposition, causes the sort
146 Ohio v. Wyandotte Chems. Corp., 401 U.S. 493, 496 (1971) (citations omitted).
Massachusetts v. EPA, 127 S. Ct. 1438, 1462â“63 (2007) (noting that although the Court has
âneither the expertise nor the authority to evaluate the policy judgmentsâ offered as justiď¬cations
for EPA inaction, such as that âa number of voluntary executive branch programs already provide an
effective response to the threat of global warmingâ or that âregulating greenhouse gases might impair
the Presidentâ™s ability to negotiate with â˜key developing nationsâ™ to reduce emissions,â these issues
âhave nothing to do with whether greenhouse gas emissions contribute to climate change.â). But see
California v. Gen. Motors Corp., 2007 U.S. Dist. LEXIS 68547, at â— 23 (âRegardless of the type of relief
sought, the Court must still make an initial policy decision in deciding whether there has been an
â˜unreasonable interference with a right common to the general public.â™â) (citation omitted).
148 Kadic v. Karadzic, 70 F.3d 232, 249 (2d Cir. 1995).
149 See Paul Sherman, Agent Orange and the Problem of the Indeterminate Plaintiff, 52 Brook. L. Rev.
369, 383 (1986) (citing In re âAgent Orangeâ Prod. Liab. Litig., 597 F. Supp. 740 (E.D.N.Y. 1984)).
David A. Grossman
of injuries afď¬‚icting the plaintiffs.150 In the climate context, scientists use computer
models to project the past and future course of Earthâ™s climate and to demonstrate
the probabilistic association between increased greenhouse gas emissions and cli-
matic effects.151 The studies and models such as those the IPCC relied upon â“ along
with the studies that scientists are continually publishing in peer-reviewed journals â“
soundly establish beyond the âmore likely than notâ standard used in the legal arena
the general causal link between greenhouse gas emissions, climate change, and
effects such as higher temperatures and sea-level rise.152
Generally, courts have not considered statistical associations like those that epi-
demiological studies produce to be adequate proof of speciď¬c causation â“ whether it
can be said that the substance caused plaintiffsâ™ particular injuries.153 This individual
causation is often the most problematic for toxic tort plaintiffs, who have to grapple
with the existence of background levels of the injuries and other risk factors that may
contribute to the injuries.154 These complications mean that even where plaintiffs
can show that defendants are responsible for a signiď¬cant proportion of the cases of a
harm, no single plaintiff can prove that he or she is one of those cases.155 Given these
difď¬culties, plaintiffs in toxic tort cases have had to supplement epidemiological
evidence with supporting scientiď¬c evidence, statistical evidence, expert testimony,
or further epidemiological evidence that shows that, more probably than not, the
risk factor in question caused their individual injuries, as opposed to any other
James Henderson & Aaron Twerski, Products Liability: Problems and Process 143 (3d
151 The basic idea of climate models is that parameters (such as temperature) numerically describing
the dynamics of the climate are represented on a grid covering the planet, dividing the globe into
little boxes. More boxes means a ď¬ner resolution for the model, but it also means more data, more
calculations, and more time, so climate models are usually averaged over relatively large geographical
areas. Climate models face uncertainty due to the complexity and interdependence of the climate sys-
tem, feedback loops, vegetation changes, ocean circulation, clouds, and many other factors. Modelling
the Climate, ClimatePrediction.net, available at http://www.climateprediction.net/science/model-
intro.php (visited Jan. 2, 2008). Conď¬dence in climate models has improved due to advances in their
performance on a range of space and time scales. Working Group I, IPCC, supra note 1, at 10, 13.
152 See Working Group I, IPCC, supra note 1. See also Chapter 1.
153 Henderson & Twerski, supra note 150, at 143.
154 Penalver, supra note 4, at 580.
155 Tom Christoffel & Stephen P. Teret, Epidemiology and the Law: Courts and Conď¬dence Intervals, 81
Am. J. Pub. Health 1661, 166â“63 (1991).
156 See Penalver, supra note 4, at 580â“81; see also Oâ™Reilly & Cody, supra note 42, at 32, and In re âAgent
Orangeâ Prod. Liab. Litig., 611 F. Supp. 1223, 1253 (E.D.N.Y. 1985) (ď¬nding inadmissible expert
opinions that do not show that Agent Orange was more likely than anything else to be the cause of
plaintiffsâ™ harms). But see Heckman v. Fed. Press Co., 587 F.2d 612, 617 (3d Cir. 1978) (âExpectancy or
statistical data about a group do not establish concrete facts about an individual.â). Courts sometimes
translate this requirement to mean a ârelative riskâ of at least two. Relative risk is the difference in
risk of acquiring a given condition between exposed and unexposed populations. If a given action
has doubled the risk of a harm occurring, then one can say that it is more probable than not that a
particular incidence of that harm was caused by that action. See Penalver, supra note 4, at 580â“81.
Tort-Based Climate Litigation 217
Showing speciď¬c causation in the climate change context could be similarly
difď¬cult in some cases. The complexity of the climate system means that several
factors are involved in producing shifts in climatic activity, such as more intense
storms or higher temperatures, which are also subject to natural ď¬‚uctuations.157
These multiple causes and background levels of climatic effects make it difď¬cult to
show that defendantsâ™ contributions to anthropogenic climate change caused any
particular incidence of a phenomenon.158 Harms caused by one particularly intense
hurricane or heat wave, for instance, are difď¬cult to tie to global climate change, as
such intense phenomena do sometimes occur naturally.
For some harms, however, there is no one particular âincidentâ for plaintiffs to
attribute. For example, the erosion that is damaging Alaskan coastal villages is very
directly connected to the general effect of retreating and thinning sea ice, which is
clearly tied to the rapidly warming Arctic.159 In other words, some harms are caused
more by trends exacerbated by climate change than by particular events.
In addition, the obstacle that speciď¬c causation poses is mitigated when govern-
ments as opposed to individuals are the plaintiffs. When states bring tort claims,
the plaintiffs have almost inď¬nite âlifespansâ and cover large amounts of territory,
allowing for an aggregation of effects over both space and time. The aggregation of
these harms makes it easier to rule out confounding factors; for instance, it is easier
to attribute one sinkhole in an Alaskan road to factors other than climate change
than it is to do so for a state full of roads and infrastructure damaged by thawing
permafrost. Natural ď¬‚uxes and confounding factors still exist, since climate change
may not cause some portion of the harms within the aggregation, but aggregation
allows plaintiffs to better establish that some present harms from climate change exist
in the broader geographic and temporal range.160
157 Penalver, supra note 4, at 581.
158 Although the scientiď¬c consensus is that a clear anthropogenic signal can be detected despite these
natural variations and confounding factors, see Working Group I, IPCC, supra note 1, and Working
Group II, Intergovernmental Panel on Climate Change (IPCC), Climate Change 2007:
Impacts, Adaptation and Vulnerability, Summary for Policymakers, Fourth Assessment
Report (2007), that reafď¬rms only generic causation. The variations and confounding factors mean
that it is difď¬cult to attribute to climate change any one manifestation of a harm generally linked to
climate change, since natural ď¬‚uxes or other factors could be the cause in that particular case. See
David R. Hodas, Standing and Climate Change: Can Anyone Complain About the Weather?, 15 J.
Land Use & Envtl. L. 451, 456 (2000). This will be a serious challenge to claims like those in Comer
v. Murphy, supra note 15.
159 See Ola M. Johannessen et al., Arctic Climate Change: Observed and Modeled Temperature and
Sea-Ice Variability, 56A Tellus 328, 330, 337 (2004) (â[A]nthropogenic forcing is the dominant cause
of the recent pronounced warming in the Arctic. . . . [T]here are strong indications that neither the
warming trend nor the decrease of ice extent and volume over the last two decades can be explained
by natural processes alone.â).
160 Cf. Recent Legislation: Torts â“ Products Liability â“ Florida Enacts Market Share Liability for Smoking-
Related Medicaid Expenditures, 108 Harv. L. Rev. 525, 528 (1994) (describing Florida law that allows
State to use statistical evidence to prove causation and damages by allowing State to aggregate harms
that large population suffers: âAlthough a statistical snapshot of excess death and disease may be an
David A. Grossman
Once plaintiffs establish these harms, the question is no longer whether defendants
have caused harms. Rather, the pertinent question becomes whether the amount of
their contributions is sufď¬cient to ď¬nd liability for damages.
4.2. Proximate Causation and the Substantiality Requirement
One could say that the entire global community is responsible for climate change
to some degree; no group of defendants could be entirely responsible for global
climate change. Nevertheless, the law of torts does not predicate defendant liability
on causing all of the plaintiffsâ™ harms.
An actorâ™s tortious conduct can be a legal cause of anotherâ™s harm if the conduct is
a âsubstantial factorâ in bringing it about.161 âSubstantialâ means that the defendantâ™s
conduct âhas such an effect in producing the harm as to lead responsible men to
regard it as a cause, using that word in the popular sense, in which there always lurks
the idea of responsibility.â162 As such, âsubstantial causeâ is something of a fuzzy
concept akin to âproximate cause,â of which substantiality is a critical element;163
inquiries into both concepts focus on similar issues of defendantsâ™ involvement in
and control over plaintiffsâ™ harms.164
inexact measure of harm to a particular individual, it accurately measures the harm to a State suing
for treatment of hundreds of thousands of Medicaid recipients.â).
161 Restatement (Second) of Torts Â§ 431 (1965); see also id. Â§ 834 (âOne is subject to liability
for a nuisance caused by an activity, not only when he carries on the activity but also when he
participates to a substantial extent in carrying it on.â); Restatement (Third) of Torts: Prod-
ucts Liability Â§ 16(a) (1998) (âWhen a product is defective at the time of commercial sale or
other distribution and the defect is a substantial factor in increasing the plaintiffâ™s harm beyond
that which would have resulted from other causes, the product seller is subject to liability for the
increased harm.â); Shetterly v. Raymark Indus., 117 F.3d 776, 780 (4th Cir. 1997) (âIn order to sustain
an action against Raymark for asbestos related injuries, Plaintiffs must prove that Raymark prod-
ucts were a substantial causative factor in their injuries.â) (internal quotation marks and citations
162 Restatement (Second) of Torts Â§ 431 cmt. a (1965); see also id. Â§ 433. The considerations in section
433 are relevant only to the degree they dilute or make insigniď¬cant the actorâ™s conduct in a particular
case. Id. at Â§ 433 cmt. d. That a third party is also a substantial factor does not in itself protect the actor
from liability. Id. at Â§ 439.
163 See Laborers Local 17 Health & Beneď¬t Fund v. Philip Morris, Inc., 191 F.3d 229, 235â“36 (2d Cir. 1999),
cert. denied, 528 U.S. 1080 (2000) (noting that critical elements of proximate cause are direct injury,
defendantâ™s acts being substantial cause of injury, and plaintiffâ™s injury being reasonably foreseeable).
See also Young v. Bryco Arms, 821 N.E.2d 1078, 1086 (Ill. 2004) (âThe proper inquiry regarding legal
cause involves an assessment of foreseeability, in which we ask whether the injury is of a type that a
reasonable person would see as a likely result of his conduct.â).
164 See City of Bloomington, Ind. v. Westinghouse Elec. Corp., 891 F.2d 611, 614 (7th Cir. 1989) (hold-
ing Monsanto not to be liable for nuisance because âWestinghouse was in control of the prod-
uct purchased and was solely responsible for the nuisance it created.â). Others outside of defen-
dantâ™s control might contribute to the harm, but courts can still ď¬nd liability if the defendant
also has some element of control by means of its tortious conduct and participation. See In re
Methyl Tertiary Butyl Ether (âMTBEâ) Prod. Liab. Litig., 175 F. Supp. 2d 593, 628â“29 (S.D.N.Y.
Tort-Based Climate Litigation 219
In several cases dealing with municipal claims against handgun manufacturers
and distributors, courts grappled with proximate causation and the degree of defen-
dantsâ™ control.165 In general, the plaintiffs in these cases alleged that the defendants
should be held liable for creating and fostering illegal markets for handguns, which
in turn allow guns to get into the hands of criminals, who then use them for illegal
and often deadly purposes.166 In one such case, the court found the causal chain
involved to be âsimply too attenuated to attribute sufď¬cient control to the manu-
facturersâ of handguns.167 The main element that made the chain âattenuatedâ was
that the manufacturers did not have an adequate degree of control over criminals
and those who diverted guns to them, and thus were not in a position to prevent the
wrongs caused by handguns diverted to unauthorized owners and criminal use.168
The causal chain in climate change tort suits would likely look something like
the following: (1) companies produce fuel, power, vehicles, etc.; (2) consumer use
of these items generates greenhouse gas emissions, which rise into the atmosphere;
(3) the emissions combine with other greenhouse gas emissions to warm the Earth;
(4) this warming causes sea levels to rise, snowpack to melt, etc.; and (5) these effects
cause damage to plaintiffsâ™ property. Arguably, this end result has been foreseeable
for several years.169 Further, the relevant companiesâ™ control does not appear to
be lacking. The only intervening parties are consumers, whose intervention is quite
foreseeable. Moreover, customers are not misusing the goods but rather are the
intended owners using the goods in the intended way;170 in fact, no misuse of power,
fuels, etc., seems possible. Given this uninterrupted causal chain, climate change
plaintiffs might thus be able to establish proximate causation.171
Camden County Bd. of Chosen Freeholders v. Beretta, U.S.A. Corp., 273 F.3d 536, 541 (3d Cir.
2001), and City of Philadelphia v. Beretta U.S.A., Corp., 126 F. Supp. 2d 882, 910â“11 (E.D. Pa. 2000);
Young v. Bryco Arms, 821 N.E.2d at 1089â“90 (all ď¬nding lack of sufď¬cient control).
166 See, e.g., Camden County Bd. of Chosen Freeholders, 273 F.3d at 538â“39.
167 Id. at 539, 541 (â(1) the manufacturers produce ď¬rearms at their places of business; (2) they sell the
ď¬rearms to federally licensed distributors; (3) those distributors sell them to federally licensed dealers;
(4) some of the ď¬rearms are later diverted by unnamed third parties into an illegal gun market, which
spills into Camden County; (5) the diverted ď¬rearms are obtained by unnamed third parties who
are not entitled to own or possess them; (6) these ď¬rearms are then used in criminal acts that kill
and wound County residents; and (7) this harm causes the County to expend resources to prevent or
respond to those crimes.â).
168 Id. at 541. Where there are intervening third parties, the issue of legal causation is whether the
intervening cause is of the type that a reasonable person would foresee as a likely result of his conduct.
Restatement (Second) of Torts Â§ 442 (1965).
169 The ď¬rst IPCC report, for instance, was in 1990. See supra note 28.
170 See Restatement (Second) of Torts Â§ 442 (1965).
171 It should be noted that at least one circuit held that proximate causation is not needed in public
nuisance claims, though this does not appear to be the majority approach. Allegheny Gen. Hosp.
v. Philip Morris, Inc., 228 F.3d 429, 446 (3d Cir. 2000) (âThe Hospitalsâ™ remaining claims of public
nuisance, aiding and abetting and civil conspiracy, restitution, unjust enrichment, quantum meruit,
and indemnity do not require proximate cause.â) (applying Pennsylvania law). But cf. Camden County
Bd. of Chosen Freeholders, 273 F.3d at 541 (âThe County argues that proximate cause, remoteness,
and control are not essential to a public nuisance claim. . . . But the relevant case law shows that, even
David A. Grossman
Of course, being a âsubstantial factorâ not only involves control but also implies
something about the size of defendantsâ™ contributions. It is clearly possible to identify
defendants who have contributed substantially to climate change and its resulting
effects. The plaintiffs in California v. GM and Connecticut v. AEP, for instance,
targeted automakers and electric utilities, respectively. In 2004, 98% of total U.S.
carbon dioxide emissions and more than 82% of total U.S. greenhouse gas emis-
sions were from fossil fuel combustion.172 Electricity generators were responsible for
consuming 34% of U.S. energy from fossil fuels and emitted 40% of the CO2 emis-
sions from fossil fuel combustion; 82% of these emissions came from coal.173 U.S.
energy-related CO2 emissions represent about 24% of the world total.174 Overall, the
generation of electricity resulted in a larger portion (33%) of total U.S. greenhouse
gas emissions in 2004 than any other activity.175 Transportation activities were not far
behind; transportation accounted for roughly 28% of greenhouse gas emissions in
2004.176 Transportation activities accounted for 33% of CO2 emissions from fossil fuel
combustion; more than 60% of these emissions resulted from gasoline consumption
for personal vehicle use.177
There are limited numbers of relevant companies in these sectors. The big three
American automakers (GM, Ford, and Chrysler) accounted for 58.7% of the U.S.
market in 2004, while the big three Japanese automakers (Toyota, Honda, and
Nissan) accounted for another 31%.178 More than 5,000 power plants generate elec-
tricity in the United States, but the 100 largest power producers in the United States
own nearly 2,000 of them and accounted for 88% of the electric power generated
(including 93% of all coal-ď¬red power) and 89% of the industryâ™s reported emissions
in 2004.179 Seven electric power producers contributed 25% of the industryâ™s carbon
dioxide emissions; nineteen producers accounted for half.180
There are also limited numbers of companies in related sectors. In 1997, twenty of
the worldâ™s petroleum and coal companies collectively accounted for roughly half
of the worldâ™s carbon emissions.181 In 2003, the largest ď¬ve oil companies operating
if the requisite element is not always termed â˜control,â™ the New Jersey courts in fact require a degree
of control by the defendant over the source of the interference that is absent here.â).
172 Energy Information Administration (EIA), Emissions of Greenhouse Gases in the United
States 2004, x, xii (Dec. 2005).
173 Environmental Protection Agency (EPA), Inventory of U.S. Greenhouse Gas Emissions
and Sinks: 1990â“2004, Executive Summary 7â“8 (2006); EIA, supra note 172, at 22.
174 EIA, supra note 172, at 3.
175 EPA, supra note 173, at 13.
176 Id. at 13â“14.
177 Id. at 7.
178 Christine Tierney, Big 3 Market Share Dips to All-Time Low, Detroit News, Jan. 5, 2005, available
at http://www.detnews.com/2005/autosinsider/0501/06/A01â“50668.htm (visited Jan. 2, 2008).
179 Ceres, Natural Resources Defense Council, & Public Service Enterprise Group, Bench-
marking Air Emissions of the 100 Largest Electric Power Producers in the United States â“
2004 at 1, 3, 7 (5th ed. Apr. 2006).
180 Id. at 3.
181 Natural Resources Defense Council (NRDC) et al., Kingpins of Carbon: How Fossil Fuel
Producers Contribute to Global Warming, Part 1 (1999).
Tort-Based Climate Litigation 221
in the United States (Exxon Mobil, Chevron Texaco, ConocoPhillips, BP, and Royal
Dutch Shell) controlled more than 14% of global oil production, 48% of domestic
oil production, more than half of domestic reď¬ning capacity, more than 61% of the
retail gasoline market, and more than 21% of domestic natural gas production.182
ExxonMobil alone is responsible for some 5% of global anthropogenic CO2 emis-
sions since 1882.183 The top ď¬ve coal producers in the United States (Peabody, Rio
Tinto, Arch, CONSOL, and Foundation) accounted for more than half of total coal
production in 2005.184
These companies could all, it seems, be defendants in a climate change suit.
Some might argue, however, that the true cause of greenhouse gas emissions is
consumption of these products rather than production of them.185 After all, it is
not car manufacturers per se, but rather the millions of individual drivers who use
their products that emit greenhouse gases. Several law and policy considerations,
however, support holding producers, but not individual consumers, liable for the
harms of climate change. First, individual consumers such as drivers and users
of electricity do not contribute âsubstantiallyâ to climate change; as such, their
small individual contributions would not meet the standards for legal causation.186
Second, the degree to which individual consumers maintain real âcontrolâ over the
harms is debatable. Individual consumers have few meaningful alternatives to fossil
fuels and the products that rely on them. Moreover, some fossil fuel companiesâ™
efforts to encourage public uncertainty about global climate change have com-
promised the level of consumer knowledge about the risks posed by fossil fuel use.187
Finally, tort lawâ™s goal of reducing the cost of âaccidentsâ would not be furthered by
placing the costs of climate change on individual consumers, but rather by holding
liable producers who can incorporate the various costs of climate change into the
prices of their products (or produce different products).188
5. RELIEF IN A CLIMATE CHANGE TORT SUIT
Climate change plaintiffs seeking either of the two basic tort remedies â“ damages or
injunctive relief â“ must consider certain issues. This section explores the standards
182 Public Citizen, Mergers, Manipulation and Mirages: How Oil Companies Keep Gaso-
line Prices High, and Why the Energy Bill Doesnâ™t Help (Mar. 2004), available at
http://www.citizen.org/documents/oilmergers.pdf (visited Jan. 2, 2008).
183 Friends of the Earth International, Exxonâ™s Climate Footprint: The Contribution of
ExxonMobil to Climate Change Since 1882 (Jan. 2004).
184 Energy Information Administration, 2005 Annual Coal Report, tbl.10.
185 NRDC et al., Kingpins of Carbon, supra note 181, Executive Summary (comparing this portrayal
to the war on drugs focusing primarily on users rather than suppliers).
186 See Restatement (Second) of Torts Â§ 834 cmt. d (1979) (âThus if the operation of a dance hall
unreasonably interferes with the comfortable enjoyment of a neighboring residence, the proprietor is
liable, but a patron normally does not participate in the objectionable activity to such an extent as to
justify imposing liability upon him for the invasion.â).
187 See supra note 34.
188 See Penalver, supra note 4, at 591.
David A. Grossman
for injunctive relief and damages (particularly in nuisance suits), the potential dam-
ages claims for which plaintiffs could seek recovery in tort-based litigation, possible
restrictions on damage recovery, and potential ways of apportioning liability among
5.1. Standards for Damages and Injunctions
The climate nuisance suits described earlier involve two different types of relief.189
In California v. GM, for instance, the State of California is seeking damages. In
determining whether to award damages in a public nuisance suit, âthe courtâ™s task is
to decide whether it is unreasonable [for the defendants] to engage in the conduct
without paying for the harm done.â190 To be compensated with a damage award,
climate change plaintiffs must have actually incurred signiď¬cant harm,191 which
California asserts it has in the form of property damage and expenses for preven-
tative measures.192 The question then becomes the unreasonableness of allowing
defendants to continue their behavior without providing compensatory damages
to the plaintiffs. Climate change plaintiffs could contend that even if defendantsâ™
activities are of great utility to society, as one could reasonably argue, it could still
be unreasonable to inď¬‚ict the harm on plaintiffs without compensating them.193
In a public nuisance action for injunctive relief, the question is whether the
defendantsâ™ activity itself is so unreasonable that the court must stop or reduce it.
Plaintiffs need only be threatened with harm and need not actually have incurred
harm yet.194 The plaintiffs in Connecticut v. AEP allege a range of threatened harms,
increased heat deaths due to intensiď¬ed and prolonged heat waves; increased
ground-level smog with concomitant increases in respiratory problems like asthma;
beach erosion, inundation of coastal land, and salinization of water supplies from
accelerated sea level rise; reduction of the mountain snow pack in California that
provides a critical source of water for the State; lowered Great Lakes water lev-
els, which impairs commercial shipping, recreational harbors and marinas, and
hydropower generation; more droughts and ď¬‚oods, resulting in property damage
and hazard to human safety; and widespread loss of species and biodiversity, includ-
ing the disappearance of hardwood forests from the northern United States.195
supra Section 1.1.
(Second) of Torts Â§ 821B cmt. i (1979).
192 âHuman-induced global warming has, among other things, reduced Californiaâ™s snow pack (a vital
source of fresh water), caused an earlier melting of the snow pack, raised sea levels along Californiaâ™s
coastline, increased ozone pollution in urban areas, increased the threat of wildď¬res, and cost the
State millions of dollars in assessing those impacts and preparing for the inevitable increase in those
impacts and for additional impacts.â Complaint, supra note 11, Âś 1. For more on types of damages that
plaintiffs can claim, see infra Section 5.2.
193 See Restatement (Second) of Torts Â§ 821B cmt. i (1979).
195 Complaint, supra note 24, Âś 3.
Tort-Based Climate Litigation 223
Courts often grant injunctions âwhen damages are inadequate, such as with
ongoing nuisances in which numerous suits or future damage awards would be
required.â196 Future suits and damage awards will be likely during the continued
progress of global climate change. It would be unreasonable and unwise, how-
ever, for a court to enjoin all emissions from defendants, since that would destroy
those companies and imperil the economy. Instead, should a court determine that
defendantsâ™ substantial carbon dioxide or other greenhouse gas emissions are unrea-
sonable, it could arguably focus injunctive relief directly on the source of plaintiffsâ™
harms by enjoining defendants from continuing greenhouse gas emissions at their
current levels, which is in fact the injunctive relief that the plaintiffs in Connecticut
seek.197 Injunctions also might theoretically mandate conservation and efď¬ciency
measures or improvement and updating of technology and equipment, if a court
thought such drastic intervention through its equity powers was warranted.
It is important to realize some of the potential implications of seeking damages
versus injunctive relief. If climate plaintiffs seek damages, they might get compen-
sation for the harms caused to them; at the same time, however, courts may be
hard pressed to deal with the many possible suits by the numerous governments
harmed by climate change, and defendants seeking to prevent such suits might
push for passage in Congress of a liability shield.198 Plaintiffs seeking damages
might also be able to recover from defendants only a relatively small percentage
of the actual damages incurred, reď¬‚ecting defendantsâ™ proportionate contribution
to the harm.199 On the other hand, climate plaintiffs seeking injunctive relief can
more directly affect the activities that are causing the present harms and risks, but
the costs of existing harms remain on the plaintiffs. It is also possible that a court
could view such relief as dictating national energy or climate policy and therefore
as prohibited by separation of powers or other justiciability concerns, as discussed
5.2. Potential Types of Damages Claims
Some of plaintiffsâ™ claims for damages would involve present harms. For instance,
in California v. GM, the State of California has asserted present damages including
reduced snow pack (a source of fresh water), higher sea levels along the coast-
line, and increased ozone pollution in urban areas.201 Many of plaintiffsâ™ dam-
ages, however, might be less tied to property already lost than to efforts that have
196 Cox v. City of Dallas, 256 F.3d 281, 291 (5th Cir. 2001) (citing Development in the Law â“ Injunction,
78 Harv. L. Rev. 997, 1001 (1965)).
197 406 F. Supp. 2d at 270 (quoting Complaint, supra note 24, 6).
198 For descriptions of discussions in the 109th Congress concerning a liability shield, see Backers of CO2
Curbs Eye Liability Relief to Bolster Industry Support, 27 InsideEPA, (No. 36), Sept. 8, 2006.
199 See infra Section 5.4.
200 See supra Section 3.3.
201 Complaint, supra note 11, 1.
David A. Grossman
been or need to be taken to prevent future harm.202 California, for instance, asserts
The State is spending millions of dollars on planning, monitoring, and infrastructure
changes to address a large spectrum of current and anticipated impacts, including
reduced snow pack, coastal and beach erosion, increased ozone pollution, sea
water intrusion into Sacramento Bay-Delta drinking water supplies, and to respond
to impacts on wildlife, including endangered species and ď¬sh, wildď¬re risks, and
the long-term need to monitor on-going and inevitable impacts.203
The general tort rule is that plaintiffs harmed by defendants are entitled to recover
their reasonable expenditures needed to abate, mitigate, or prevent future recur-
rences of those harms.204 For more than a century, for example, courts have held
that plaintiffs can recover from defendants their reasonable expenditures for erecting
walls to keep water off of their property.205 These precedents seem directly applica-
ble to efforts to prevent or mitigate harms from sea-level rise (e.g., building levees,
elevating houses and infrastructure). Given the high levels of conď¬dence with which
the IPCC and other scientists have established these present and projected impacts,
preventative measures seem reasonable.206 Plaintiffs thus should be able to properly
include the expenses for these preventative measures in the scope of damages.
In addition, one could view damages sought for monitoring as analogous to a
medical monitoring claim, often asserted in cases involving exposure to a substance
such as asbestos.207 The basic claim in those cases is that defendantsâ™ negligence in
exposing plaintiffs to hazardous substances so increased the risk of adverse health
consequences that the defendants should be liable for the present, quantiď¬able costs
to plaintiffs of being tested periodically for signs of the illness.208 Some courts require
202 Although such claims involve future harms, they should not be hindered by courtsâ™ general reluctance
to award damages for future or latent injuries. In cases involving asbestos, for example, courts have
hesitated to award damages for fear that the injuries may never actually occur. See, e.g., Lavelle v.
Owens Corning Fiberglass Corp., 507 N.E.2d 476, 479 (Ohio Ct. Com. Pl., Cuyahoga Cty. 1987);
Mauro v. Raymark Indus., 561 A.2d 257 (N.J. 1989). These climate change claims, in contrast, would
seek compensation not for future harms, but rather for the present actions needed to prevent them.
203 Complaint, supra note 11, 4.
204 See generally M.O. Regensteiner, Annotation, Expense Incurred by Injured Party in Remedying Tempo-
rary Nuisance or in Preventing Injury as Element of Damages Recoverable, 41 A.L.R. 2d 1064 (2001). See
also Restatement (Second) of Torts Â§ 930(3)(b) (1979) (allowing damages for past and prospective
invasions of land to include compensation for reasonable cost to plaintiff of avoiding future invasions).
205 See Regensteiner, supra note 204, at Â§ 3(c) (citing Comstock v. New York C. & H.R.R. Co., 48 Hun.
225 (N.Y. 1888) (holding building owner who constructed concrete wall to prevent water from broken
pipe on defendantâ™s premises from ď¬‚owing into his cellar entitled to recover expense of constructing
wall) and Piedmont Cotton Mills, Inc. v. Gen. Warehouse, Inc., 149 S.E.2d 72 (Ga. 1966) (holding
that where defendantâ™s diversion of stream into artiď¬cial watercourse resulted in ď¬‚ooding to abutting
property of plaintiff, cost of plaintiffâ™s protective measures were properly element of damage)).
206 See Working Group II, IPCC, supra note 158. See also Chapter 1.
207 See, e.g., Marine Asbestos Cases v. Am. Hawaiian Cruises, Inc., 265 F.3d 861 (9th Cir. 2001).
208 See id. at 866; see also David Rosenberg, The Causal Connection in Mass Exposure Cases: A âPublic
Lawâ Vision of the Tort System, 97 Harv. L. Rev. 851, 886 (1984). Even some courts that reject
enhanced-risk claims accept the less-speculative medical monitoring claims. See, e.g., Mauro v.
Tort-Based Climate Litigation 225
present physical impacts or symptoms in order to make such a claim,209 but many
focus solely on whether the monitoring is reasonably necessary and will produce a
real beneď¬t.210 Courts recognizing monitoring claims often do so to encourage early
detection and mitigation of the harm.211 In the climate context, a system to monitor
water supply levels, for instance, could have real beneď¬t by allowing early mitigation
action.212 Plaintiffs such as California thus might be able to recover reasonable
monitoring expenses as well.
5.3. Restrictions on Damage Recovery
Although the damages may be cognizable, plaintiffs still might be unable to recover
for some of their harms. If the property damaged or for which plaintiffs took pre-
ventative actions is private property, the remoteness doctrine might preclude gov-
ernmental plaintiffs from recovering their own costs. The doctrine of remoteness
bars recovery in tort for indirect harm suffered as a result of injuries directly sus-
tained by another person.213 Courts sometimes deem expenditures by a state that
are inescapably contingent on direct or speculative harm to state residents to be too
derivative or remote to support a tort claim.214 The damages to homes from sea-level
rise, for instance, might prove too derivative for a state to assert.
Nonderivative harms, however, could sustain a tort claim. For instance, if the
damaged property was public, as are many beaches, roads, and other infrastructure,
then the government itself is harmed. Diminished property tax revenues and lower
property values also can harm states apart from any harm to individuals.215 Further,
even if some of the statesâ™ injuries arise from harm to others, states and their citizens
have a relationship that can sometimes overcome the remoteness doctrine.216
Raymark Indus., Inc., 561 A.2d 257, 263 (N.J. 1989); In re Paoli R.R. Yard PCB Litig., 916 F.2d 829, 850
(3d Cir. 1990).
209 See, e.g., Mergenthaler v. Asbestos Corp. of Am., 480 A.2d 647, 651 (Del. 1984); Villari v. Terminix
Intâ™l, Inc., 677 F. Supp. 330, 338 (E.D. Pa. 1987). Climate âsymptomsâ were described in Chapter 1.
210 See, e.g., Paoli, 916 F.2d at 851 (â[T]he appropriate inquiry is not whether it is reasonably probable
that plaintiffs will suffer harm in the future, but rather whether medical monitoring is, to a reasonable
degree of medical certainty, necessary in order to diagnose properly the warning signs of disease.â);
see also Marine Asbestos Cases, 265 F.3d at 866; Mauro, 561 A.2d at 263.
211 See Paoli, 916 F.2d at 852 (describing these as âconventional goals of the tort systemâ); see also Potter
v. Firestone Tire & Rubber Co., 863 P.2d 795, 824 (Cal. 1993).
212 An imperfection in the analogy is that for medical monitoring claims, the damage is to the human
body, whereas the harms from climate change are largely to property or other interests. Courts might
view these damages to be less urgent and therefore less in need of legal innovation. Monitoring systems
to detect something like the northward spread of tropical diseases as the climate warms, however, might
ď¬t more squarely into the usual human health paradigm.
213 See State v. Lead Indus. Assâ™n, No. 99-5226, 2001 R.I. Super. LEXIS 37, at â— 44 (R.I. Super. Apr. 2, 2001)
214 See, e.g., id. at â—â— 44â“46.
215 See City of Boston v. Smith & Wesson Corp., No. 1999-02590, 2000 Mass. Super. LEXIS 352, at â— 24
(Mass. Super. July 13, 2000) (memorandum of decision and order on defendantsâ™ motion to dismiss).
216 See Massachusetts v. EPA, 127 S. Ct. 1438, 1454 (2007) (quoting Georgia v. Tenn. Copper, 206 U.S.
230, 237 (1907): âThis is a suit by a State for an injury to it in its capacity of quasi-sovereign. In that
David A. Grossman
The municipal cost recovery rule could pose another obstacle to recovery of some
damages by climate change plaintiffs. Generally, a municipality may not recover
the costs of providing public services.217 âThe cost of public services for protection
from a safety hazard is to be borne by the public as a whole, not assessed against
a tortfeasor whose negligence creates the need for the service.â218 What the cases
barring recovery under the municipal cost recovery rule have in common is that the
acts causing the damage were of the sort that the municipality reasonably could have
expected to occur.219 Courts have recognized, however, that governments can recover
their expenses for abatement of public nuisances (such as cleanup of toxic wastes
discharged into drinking water supplies) and for protection of the governmentâ™s own
property.220 Which climate-related expenses are truly unexpected will largely be a
question for the courts.221
5.4. Liability for and Apportionment of Damages
When multiple actors cause a harm, which appears to be the case with climate
change plaintiffsâ™ injuries, the critical question is the amount of damages for which
courts should hold the defendants collectively and individually liable. If there is a
reasonable basis for dividing the harm according to each defendantâ™s contribution,
each is liable only for that portion of the total harm that each has caused.222 If the
harm is an indivisible harm, all parties that are legal causes of the harm are jointly
and severally liable for the entire harm.223
On their face, the harms from climate change appear to be indivisible. In Michie
v. Great Lakes Steel Division,224 several people residing near Ontario, Canada, sued
three corporations operating seven plants immediately across the Detroit River in
capacity the State has an interest independent of and behind the titles of its citizens, in all the earth
and air within its domain. It has the last word as to whether its mountains shall be stripped of their
forests and its inhabitants shall breathe pure air.â). See also City of Boston, 2000 Mass. Super. LEXIS
352 at â—â— 26â“27.
217 City of Philadelphia v. Beretta U.S.A., Corp., 126 F. Supp. 2d 882, 894â“95 (E.D. Pa. 2000); City of
Boston, 2000 Mass. Super. LEXIS 352, at â—â— 30â“32.
218 City of Philadelphia, 126 F. Supp. 2d at 894 (quoting City of Pittsburgh v. Equitable Gas Co., 512 A.2d
83, 84 (Pa. Commw. Ct. 1986)).
219 City of Boston, 2000 Mass. Super. LEXIS 352, at â—â— 33â“34.
220 See City of Flagstaff v. Atchison, Topeka & Santa Fe Ry. Co., 719 F.2d 322, 324 (9th Cir. 1983); Town
of E. Troy v. Soo Line R.R. Co., 653 F.2d 1123, 1132 (7th Cir. 1980), cert. denied, 450 U.S. 922 (1981).
221 Courts can disagree on what are reasonably expected municipal costs. Compare City of Philadelphia,
126 F. Supp. 2d at 894â“95 (noting that at least three courts â“ in Ohio, Florida, and Connecticut â“ have
held that municipal cost recovery rule bars citiesâ™ suits against gun industry for recovery of expenses of
policing cities), with City of Boston, 2000 Mass. Super. LEXIS 352, at â— 34 (âPlaintiffs allege wrongful
acts [by the gun industry] which are . . . [not] of the sort a municipality can reasonably expect.â).
222 Restatement (Second) of Torts Â§ 881 (1979); see also Restatement (Third) of Torts: Products
Liability Â§Â§ 16(a), (b) (1998).
223 Restatement (Second) of Torts Â§Â§ 875, 879 (1979); see also Restatement (Third) of Torts:
Products Liability Â§ 16(c) (1998).
224 495 F.2d 213 (6th Cir. 1974).
Tort-Based Climate Litigation 227
the United States, claiming that pollutants emitted by defendantsâ™ plants were a
nuisance. Each plaintiff sought damages from all three corporate defendants jointly
and severally. The Sixth Circuit held that âalthough there is no concert of action
between tort-feasors, if the cumulative effects of their acts is a single indivisible injury
which it cannot certainly be said would have resulted but for the concurrence of
such acts, the actors are to be held liable as joint tort-feasors.â225 This joint liability
exists and operates regardless of the existence of âother corporations, persons and
instrumentalitiesâ that contributed to the air pollution âso as to make it impossible
to prove whose emissions did what damage to plaintiffsâ™ persons or homes.â226 If the
judge or jury determines that it is not practicable to apportion the harm among the
tortfeasors, âthe entire liability may be imposed upon one (or several) tortfeasors
subject, of course, to subsequent right of contribution among the joint offenders.â227
The Michie court therefore shifted from the injured party to the defendants the
burden of proof as to which defendant was responsible for the relevant harms, and
to what degree.228
One understandably could view holding defendants jointly and severally liable for
the entirety of plaintiffsâ™ harms from climate change as unfair. Because greenhouse
gases have long lifespans in the atmosphere, past emissions are contributors to cli-
mate change. Accordingly, if courts assign all damages to current companies, those
companies would be liable for past emissions to which they have no connection.229
Furthermore, although those companies are âsubstantialâ contributors, there are still
other parties who have contributed somewhat to climate change as well. To avoid
such inequity, courts may require apportionment even where harms seem indivisible
if some means of fair and rational apportionment is possible without causing injustice
to any of the parties.230 In pollution cases, for instance, courts can treat a seemingly
at 216 (quoting Watts v. Smith, 134 N.W.2d 194 (Mich. 1965)).
227 Id. at 217; see also Martin v. Owens-Corning Fiberglass Corp., 528 A.2d 947 (Pa. 1987).
228 Michie, 495 F.2d at 218. Courts have replicated the Michie holding in other pollution contexts. See,
e.g., Landers v. E. Tex. Salt Water Disposal Co., 248 S.W.2d 731, 734 (Tex. 1952); Velsicol Chem. Corp.
v. Rowe, 543 S.W.2d 337, 342â“43 (Tenn. 1976); Commonwealth v. PBS Coals, Inc., 534 A.2d 1130, 1139
(Pa. 1987). The Restatement incorporated the holding as well. See Restatement (Second) of Torts
Â§Â§ 433A, 433B, 875, 879 (1965). A similar rule exists in products liability, in which a manufacturer is
liable for the increased harm caused to plaintiffs by his product (beyond the harm that would have
otherwise occurred). If the manufacturer cannot show what harm would have occurred absent the
product defect, he can be liable for all of plaintiffsâ™ harms. See Restatement (Third) of Torts:
Products Liability Â§ 16 (1998).
229 See Christopher D. Stone, Beyond Rio: âInsuringâ Against Global Warming, 86 Am. J. Intâ™l L. 445,
468 (1992). However, global CO2 emissions skyrocketed in the twentieth century, particularly in the
latter half, and have continued to do so at the start of the twenty-ď¬rst century, thus playing a much
larger role in altering the atmospheric concentrations of carbon dioxide. See UNEP/GRID-Arendal,
Global atmospheric concentration of CO2 (2005) (graph showing the increase in CO2 levels in the
atmosphere from 1870 to 2004 and predicted levels to the year 2100), available at http://maps.grida.no/
go/graphic/global atmospheric concentration of co2 (visited Jan. 2, 2008).
230 See Restatement (Second) of Torts Â§ 433A cmt. d (1965); see also id. Â§ 433B cmt. e.
David A. Grossman
indivisible harm as divisible and apportion it among defendants on the basis of evi-
dence of their respective quantities of pollution discharged.231 In the climate context,
this division could involve apportioning damages (appropriately reduced to account
for past emissions) based on the global warming potential of their greenhouse gas
emissions, to correspond as much as possible to each defendantâ™s contributions to
climate change.232 On the other hand, apportioning damages in accordance with
each defendantâ™s contribution to climate change might provide plaintiffs with only
a small percentage of the damages they are suffering. Courts will have to ď¬nd a
balance between equitable apportionment and adequately compensatory damages.
Tort-based climate change litigation strikes many people as a strange idea at ď¬rst.
Basic tort principles, however, combined with the overwhelming scientiď¬c consensus
that global climate change is occurring and is having present detrimental effects,
may provide a basis for liability claims against major corporate emitters for some of
climate changeâ™s effects.
Public nuisance seems to be the strongest of the climate tort claims, although it
is possible that a products liability suit or some other tort claim could prove viable.
Particularly in light of the recent Supreme Court decision in Massachusetts v. EPA,
climate plaintiffs should be able to establish standing; the other jurisdictional issues
of preemption and justiciability, while much less clear cut than standing, also may
not present insurmountable obstacles. Plaintiffs should be able to establish generic
and speciď¬c causation, particularly state plaintiffs who can aggregate harms over
time and space, and there are several potential defendants who could be said to have
proximately caused the plaintiffsâ™ harms by means of their substantial contributions
to global climate change. Should climate plaintiffs clear the jurisdictional hurdles
and succeed on the merits of their cases, they could seek injunctive relief or damages
for a range of costs incurred, likely apportioned among defendants in some way that
recognizes both their relative contributions of greenhouse gas emissions and the
compensatory needs of plaintiffs.
id. Â§ 433A cmt. d (1965).
Penalver, supra note 4, at 592. Global warming potentials provide a quantiď¬ed measure of the
impact of a particular greenhouse gas on climate change. Carbon dioxide is the biggest contributor
to climate change because of its volume, but other greenhouse gases are much more potent. See
EPA, supra note 173, at 3. The Agent Orange settlement employed a similar system for apportioning
damages, with reference to both market-share and dioxin content. See Ellen Tannenbaum, Note, The
Pratt-Weinstein Approach to Mass Tort Litigation, 52 Brook. L. Rev. 455, 486 n.190 (1986) (citing The
Bargaining Behind the Agent Orange Deal, Bus. Wk., May 21, 1984, at 39). But see Allen Rostron,
Beyond Market Share Liability: A Theory of Proportional Share Liability for Nonfungible Products,
52 UCLA L. Rev. 151, 170â“73, 215 (2004) (describing skepticism of courts, scholars, and Restatement
drafters to applying ârisk-adjusted market share liability,â though arguing that courts should recognize
that âfungibility is not essential if liability can be allocated in a way that reasonably accounts for the
differing levels of risk created by each defendant.â).
Tort-Based Climate Litigation 229
In sum, although there are some interesting issues involved and courts have dis-
missed the early cases, it seems that at least some tort-based climate change suits
have strong legal merits and may be capable of succeeding. Like sea level and tem-
peratures, the number of such cases likely will continue to rise over the next several
Insurance and Climate Change Litigation
Jeffrey W. Stempelâ—
To date, most discussion of insurance in relation to climate change has concen-
trated on the problem of insuring against damage wrought by natural disasters such
as Hurricane Katrina, and the particularly destructive 2004 hurricane season.1 Sig-
niď¬cant media attention has addressed the posited impact of climate change upon
the severity of what insurers term âenvironmental risksâ â“ property losses occasioned
by hurricane, ď¬‚ood, storms, or Earth movement.2 Most reports focus on property
insurance held by persons or entities suffering loss. These losses involve so-called
â— Doris S. & Theodore B. Lee Professor of Law, William S. Boyd School of Law, University of Nevada
See, e.g., Robert J. Rhee, Catatrophic Risk and Governance After Hurricane Katrina: A Postscript to
Terrorism Risk in a Post-9/11 Economy, 39 Ariz. St. L.J. 582, 591â“602 (2007); Lavonne Kuykendall,
Chubb to Offer Flood Insurance for Some Upscale Customers, Wall St. J., Dec. 21, 2006, at D2, col.
1; Liam Pleven, Hurricane Losses Prompt Allstate to Pursue New Path, Wall St. J., Nov. 24, 2006, at
A1, col. 1.
See, e.g., Killer Hurricanes: No End in Sight, Natâ™l Geographic (Aug. 2006). See generally Jeffrey
W. Stempel, From Johnstown to New Orleans: The Law and Practice of Insurance of Environmen-
tal Risks in the USA, in Die Versicherung von Umweltrisiken (âInsurance of Environmen-
tal Risksâ) (Alexander Bruns & Zdenko Grobenski eds.) (Kompentenzzenturm Versichungswis-
senschaft 2007) (describing major categories of environmental risks and the structure of United
States risk management and legal environment regarding risks); 2006 Catastrophes Cost Worldâ™s
Insurers $15 Billion, Lightest Hit in Years, Swiss Re Estimates, Ins. J., Dec. 20, 2006, available at
In this context, âenvironmental riskâ means risk of loss from widespread natural phenomenon, as
distinguished from pollution-related losses that may also be labeled âenvironmentalâ losses. Environ-
mental risks are viewed as particularly difď¬cult by insurers because they involve substantial destruction
across a wide expanse and thus present âcorrelatedâ risk (i.e., a single hurricane or ď¬‚ood affects an
entire neighborhood or town) rather than the âuncorrelatedâ risk insurers prefer (e.g., ď¬re, theft, and
even most weather conditions such as hail or lightning, which tend not to affect every house on the
block) since under these conditions the insurer is unlikely to be faced with a large number of claims at
the same time. Gradually rolling uncorrelated losses permit insurers to earn more investment income.
See Mark S. Dorfman, Introduction to Risk Management and Insurance 19â“23 (8th ed. 2004);
Emmett J. Vaughan & Therese Vaughan, Fundamentals of Risk and Insurance 652 (8th ed.
1999); Stempel, From Johnstown to New Orleans, supra, at 5â“10. By contrast, a large correlated prop-
erty loss such as Hurricane Katrina or the September 11, 2001, destruction of the World Trade Center
towers, produces a âcapital shockâ to the insurance markets due to the bunching of so many claims.
Insurance and Climate Change Litigation 231
âď¬rst-partyâ insurance in which the policyholder (the ď¬rst party) makes a claim for
repayment of its loss by the insurer (the second party), who in return for a fee (the
premium) agreed to indemnify the policyholder should it incur a covered loss.3 As
Hurricane Katrina made all too clear, many Americans are underinsured, particu-
larly with respect to ď¬‚ood insurance.4
The public policy debate over effective national risk management policy for
property promises to be interesting, even though the realities of political gridlock
give little optimism for progress. But however interesting or important, these debates
about national insurance and disaster policies tend not to include much analysis of
the type of insurance most relevant to climate change litigation, liability insurance,
which is potentially at issue when third parties sue policyholders who allegedly inď¬‚ict
This chapter uses California v. General Motors5 as a starting point for exploring
the liability insurance issues potentially raised by climate change litigation. In Cali-
fornia v. General Motors, the State of California brought an action under the tort
liability theory of âpublic nuisance.â The State alleged that automobile manufacture
and sale resulted in substantial production of carbon gases, in turn leading to adverse
climate change causing discernible harm to State property. This chapter introduces
the case, puts it in the broader context of liability insurance, considers potential
insurer defenses to providing coverage, and explores the political and economic
implications of insurance company payments for climate change litigation.
1. IMPLICATIONS FOR LIABILITY INSURANCE OF PENDING CLIMATE
Most litigation in the United States alleging climate changeâ“based causes of action
against defendants has focused on either regulatory compliance or mandating
reduced carbon emissions. California v. General Motors is the most prominent
case thus far seeking damages from private entities rather than regulatory change
by government.6 Although this case, like other climate nuisance cases to date, was
See Emeric Fischer, Peter Nash Swisher & Jeffrey W. Stempel, Principles of Insurance
Law Â§ 1.01 (3d ed. 2004) (addressing ď¬rst-party/third-party distinction and differences between property
and liability insurance); Robert H. Jerry, II, Understanding Insurance Law Â§ 13 (3d ed. 2002)
See, e.g., Leonard v. Nationwide Ins. Co., 2006 U.S. Dist. LEXIS 60079 (S.D. Miss. Aug. 15, 2006)
(homeowner unsuccessfully seeks compensation under windstorm coverage provided by standard
homeownerâ™s policy, which excludes ď¬‚ood-related losses; court holds exclusion to encompass losses
caused by storm surge from hurricanes).
See Complaint, California ex rel. Bill Lockyer, Attorney Gen. v. Gen. Motors Corp., Case No. C06â“
05755 (N.D. Cal. Sept. 20, 2006), available at http://ag.ca.gov/newsalerts/cms06/06â“082_0a.pdf.
For example, in the Introduction to this book, coeditors Wil Burns and Hari Osofsky note that U.S.
climate change cases have ranged from 1. Massachusetts v. EPA; 2. a suit against two U.S. gov-
ernment agencies â“ the Export Import Bank and the Overseas Private Investment Corporation â“
for allegedly funding transnational fossil fuel-based energy projects that generate substantial green-
house gas emissions without adequate environmental assessment under the National Environmental
Jeffrey W. Stempel
dismissed at the district court level on political question grounds, the possibility of
appellate reversal and future actions make this construct important to explore.7
In regulatory litigation, the identity of the defendants and the regulatory nature
of the case effectively preclude involvement by liability insurers. Liability insurance
ordinarily is triggered only when the policyholder is sued in an action seeking to
hold the policyholder liable for causing bodily injury or property damage in which
Policy Act (NEPA); 3. a public nuisance suit against several major power companies; and 4. a petition
to the U.S Fish and Wildlife Service to list the polar bear as an endangered species under the Endan-
gered Species Act on the grounds that climate change is imperiling the [polar bearâ™s] future. In a
German case which recently settled, advocates demanded information from an agency providing risk
insurance about the greenhouse gas emissions produced by its overseas projects. A Nigerian federal
court action characterized gas ď¬‚aring as a constitutional rights violation not only because of the direct
small-scale impacts, but also because of those localitiesâ™ vulnerability to the effects of climate change.
See Overview: The Exigencies That Drive Potential Causes of Action for Climate Change, this
volume; see also Hari M. Osofsky, The Geography of Climate Change Litigation: Implications for
Transnational Regulatory Governance, 83 Wash. U. L.Q. 1789, 1819â“50 (2006) (discussing these and
other cases in more detail); Hari M. Osofsky, Climate Change Litigation as Pluralist Legal Dialogue?,