By Sabrina McCormick,1 Samuel J.
Simmens,1 Robert L. Glicksman,2 LeRoy
Paddock,2 Daniel Kim,3 Brittany Whited,1
Whereas the executive and legislative branches are the principal reposi- tories of policy-making authority in the United States, decisions in the judicial branch have and promise to continue having an influence
on activities responsible for greenhouse gas
(GHG) emissions, energy development, and a
wide range of other government policy. The
courts are a central avenue for development
of climate-related policy in the United States.
Yet we know few details about whether and
how climate science plays a role in such judicial responses. We suggest that the role of
science is changing, that novel legal theories
are emerging, and that litigation is likely to
continue to increase.
Relatively little research has assessed the
SCIENCE IN CRITICAL CLIMATE CASES
nature and impact of judicial resolution of
climate-related actions, especially in com-
parison to the voluminous literature on
efforts to tackle climate change at the U.S.
Environmental Protection Agency (EPA)
and in progressive states such as Califor-
nia. The research that has been conducted
attests to the importance of the judiciary,
noting a “rapidly building wave” of climate
litigation (1) and that “novel and creative
legal approaches to climate change are be-
ing asserted and offer hope for resolving the
unprecedented climate crisis facing society”
(2). There has also been a corresponding
increase in litigation by those opposing ad-
ditional regulation of GHG emissions.
Science issues associated with climate change
are not unlike previous major controversies
that spurred litigation, such as those involving tobacco use and chemical exposures.
Those cases may provide insights into possible developments in climate litigation, but
climate change may give rise to unique judicial responses.
Science has played a central role in the
resolution of various types of climate cases
dealing with, e.g., air pollution, biodiversity,
and adaptation. Climate science, for ex-
ample, is critical to determining whether
litigants have standing to sue, and to sub-
stantiating that defendants’ actions have
caused the plaintiffs’ alleged harm. Absent
standing to sue, a court must dismiss the
lawsuit without even addressing the merits
(3). In Massachusetts v. EPA, the Supreme
Court ruled that the state had standing be-
cause the link between climate change and
inundation of coastal land, which the state
owns or for which it has a public trust re-
sponsibility, is scientifically supported (4).
By contrast, even though the causal link
between climate change and phenomena
such as rising sea levels is well established,
and even if litigants can establish that GHG
emissions in the aggregate are largely re-
sponsible for climate change, plaintiffs thus
far have been unable to muster scientific
support that establishes a causal link be-
tween a particular source or group of sources
of GHG emissions and the climate-related
harms they have suffered. This inability to
establish a causal link has resulted in cases
being dismissed [e.g., a federal district court
dismissed a suit by the Native Alaskan Vil-
lage of Kivalina against a large number of oil
companies based on lack of standing (5, 6)].
Climate science was important in a case
where Vermont’s decision to adopt regulatory standards enacted by California to limit
GHG emissions from automobiles was upheld (7). Another court vacated the U.S. Fish
and Wildlife Service’s decision to delist grizzly bears as under the federal Endangered
Species Act (ESA) because of studies showing
that climate change threatened the bears’
food sources (8). Litigants have successfully
prompted judicial responses to ensure that
a government agency properly considers climate science in its decision-making (9).
QUANTIFYING SCIENCE IN LITIGATION
We systematically investigate the role of science, and climate science in particular, in federal and state litigation in the United States
in cases decided between 1990 and 2016 (see
supplementary materials). We started with
a list of all climate-related and coal-fired
power plant (CFPP) cases filed in the United
States, as cataloged by the Sabin Center for
Climate Change Law at Columbia University,
New York. We characterized cases by reading
court decisions and searching for key terms
that represent the type and amount of science considered in judicial decisions.
The level and type of science relied on by
Science in litigation, the third
branch of U.S. climate policy
The context and role of climate science in court are changing
1 The George Washington University Milken Institute School
of Public Health, Washington, DC 20052, USA. 2The George
Washington University Law School, Washington, DC 20052, USA.
3The Trachtenberg School of Public Policy and Public
Administration, The George Washington University,
Washington, DC 20052, USA. Email: firstname.lastname@example.org
CAA NEPA CEQA ESA
Role of science
Type and amount of science used in decisions
Includes cases decided between 2006 and 2016 where the law invoked was the Clean Air Act (CAA, n = 192),
the National Environmental Policy Act (NEPA, n = 118), the California Environmental Quality Act (CEQA, n = 106),
or the Endangered Species Act (ESA, n = 45). Cases with unclear science roles were excluded (n = 10).