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RESEARCH ARTICLE
The Scientific Consensus on Climate Change
as a Gateway Belief: Experimental Evidence
Sander L. van der Linden
1
*, Anthony A. Leiserowitz
2
, Geoffrey D. Feinberg
2
, Edward
W. Maibach
3
1Department of Psychology and Woodrow Wilson School of Public and International Affairs, Princeton
University, Princeton, New Jersey, United States of America, 2Yale Project on Climate Change
Communication, School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut,
United States of America, 3Center for Climate Change Communication, Department of Communication,
George Mason University, Fairfax, Virginia, United States of America
*sander.vanderlinden@princeton.edu
Abstract
There is currently widespread public misunderstanding about the degree of scientific con-
sensus on human-caused climate change, both in the US as well as internationally. More-
over, previous research has identified important associations between public perceptions of
the scientific consensus, belief in climate change and support for climate policy. This paper
extends this line of research by advancing and providing experimental evidence for a “gate-
way belief model”(GBM). Using national data (N = 1104) from a consensus-message experi-
ment, we find that increasing public perceptions of the scientific consensus is significantly
and causally associated with an increase in the belief that climate change is happening,
human-caused and a worrisome threat. In turn, changes in these key beliefs are predictive of
increased support for public action. In short, we find that perceived scientific agreement is an
important gateway belief, ultimately influencing public responses to climate change.
INTRODUCTION
The scientific consensus that human activities are the primary driver of global climate change
is now unequivocal. This consensus is found not only in the latest Intergovernmental Panel on
Climate Change (IPCC) report [1], but also by several different studies, including surveys of ex-
perts [2] and comprehensive reviews of the peer-reviewed literature on climate change [3][4]
[5]. All of these methods converge on the same basic conclusion: at least 97% of climate scien-
tists have concluded that human-caused climate change is happening [6].
Yet, although a scientific consensus on this basic fact has been reached, much of the public re-
mains largely unaware of this, both in the US as well as internationally [7,8]. For example, only
one in ten Americans (12%) correctly estimate scientific agreement at 90% or higher [7]. More-
over, influential ideological and politically-motivated actors, also known as “manufacturers of
doubt”, publicly dispute the existence of the scientific consensus [9,10], including recent media
articles such as the “Myth of the Climate Change 97%”[11]. These efforts to undermine public
understanding of the scientific consensus have arguably been quite successful, with cascading
PLOS ONE | DOI:10.1371/journal.pone.0118489 February 25, 2015 1/8
OPEN ACCESS
Citation: van der Linden SL, Leiserowitz AA,
Feinberg GD, Maibach EW (2015) The Scientific
Consensus on Climate Change as a Gateway Belief:
Experimental Evidence. PLoS ONE 10(2): e0118489.
doi:10.1371/journal.pone.0118489
Academic Editor: Kristie L Ebi, University of
Washington, UNITED STATES
Received: September 30, 2014
Accepted: January 18, 2015
Published: February 25, 2015
Copyright: © 2015 van der Linden et al. This is an
open access article distributed under the terms of the
Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any
medium, provided the original author and source are
credited.
Data Availability Statement: All relevant data are
within the paper.
Funding: This research has been funded, in part, by
the American Association for the Advancement of
Science (AAAS) and the Rockefeller Family Fund
(RFF) as well as by Lawrence Linden, Robert
Litterman and Henry Paulson. The funders had no
role in study design, data collection and analysis,
decision to publish, or preparation of the manuscript.
Competing Interests: The authors have declared
that no competing interests exist.
effects on public understanding that climate change is happening, human caused, a serious
threat, and in turn, support for climate change mitigation and adaptation policies.
In light of the growing ideological divide on the issue [12] (paired with people’s tendency to
selectively process information), some scholars have argued that merely educating the public
about the scientific consensus is unlikely to be a helpful approach [13,14]. To better under-
stand how people think, process and respond to the scientific consensus message, this study in-
vestigates a “gateway belief model”(GBM) of public responses to climate change.
The Gateway Belief Model (GBM)
Perceived expert consensus plays an important role in the formation of public attitudes towards
and the acceptance of general scientific principles, including climate change [15,16]. In fact, mis-
perceptions of the scientific consensus can be highly consequential, as even a small amount of
perceived scientific dissent can undermine public support [17]. For example, a recent nationally
representative study [18] found that the degree of perceived scientific agreement influences key
beliefs about global warming, which in turn, drive public support for climate change policies.
McCright, Dunlap & Xiao [19] successfully replicated these results in a recent independent study
and similarly point to the robust role of perceived scientific agreement in generating public sup-
port for climate change policies.
Yet, past research in this area suffers from one major short-coming: the bulk of these findings
are based on cross-sectional survey data and thus correlational in nature. To date, there have been
no controlled representative experiments (or longitudinal studies) investigating the proposed caus-
al relationship between public perceptions of thescientificconsensusonclimatechangeandsup-
port for public action. This study builds upon and extends prior research in a novel direction by
directly testing the “gateway belief”model experimentally. We posit that belief or disbelief in the
scientific consensus on human-caused climate change plays an important role in the formation of
public opinion on the issue. This is consistent with prior research, which has found that highlight-
ing scientific consensus increases belief in human-caused climate change [15]. More specifically,
we posit perceived scientific agreement as a “gateway belief”that either supports or undermines
other key beliefs about climate change, which in turn, influence support for public action. A sche-
matic overview of the “gateway belief model”is presented in Fig. 1. Specifically, we hypothesize
that an experimentally induced change in the level of perceived consensus is causally associated
with a subsequent change in the belief that climate change is (a) happening, (b) human-caused,
and (c) how much people worry about the issue (H1). In turn, a change in these key beliefs is sub-
sequently expected to lead to a change in respondents’support for societal action on climate change
(H2). Thus, while the model predicts that the perceived level of scientific agreement acts as a key
psychological motivator, its effect on support for action is assumed to be fully mediated by key be-
liefs about climate change (H3).
Method
Sample and Participants
This analysis draws upon results from a recent experiment that investigated how to effectively
communicate the scientific consensus on climate change (full details of the experiment, sample
and materials are available and described in van der Linden et al. [20]). The purpose of the exper-
iment was to test the efficacy of different ways to communicate the consensus-message (e.g., de-
scriptive text, a pie chart, metaphors etc.). In total, 11 different treatment conditions were
administered. The experiment was conducted using an online national quota sample (N = 1104)
obtained from a major vendor (Survey Sampling International). The study was approved by the
The Scientific Consensus on Climate Change as a Gateway Belief
PLOS ONE | DOI:10.1371/journal.pone.0118489 February 25, 2015 2/8
Yale Institutional Review Boards for ethical research (Human Research Protection Program)
and participants signed a consent form with the sampling company (SSI) through which they
chose to participate. A descriptive overview of the sample characteristics is provided in Table 1.
Fig 1. The Gateway Belief Model (GBM).
doi:10.1371/journal.pone.0118489.g001
Table 1. Overview of sample characteristics and key belief measures.
Sample (N= 1,104)
Demographic characteristics
Gender (female %) 52
Age (modal bracket, 18, 75+) 35–44
Education (bachelor's degree or higher %) 36
Party Affiliation (% Democrat) 38
Key climate change beliefs (0–100) Pre-Test Mean Post-Test Mean Difference (S.E.)
Estimate of Scientific Consensus 66.98 79.72 12.74 (0.71)
Belief in Climate Change 73.08 77.01 3.93 (0.55)
Human Causation 63.98 68.02 4.04 (0.47)
Worry about Climate Change 62.84 67.32 4.48 (0.39)
Support for Public Action 75.19 76.88 1.69(0.41)
doi:10.1371/journal.pone.0118489.t001
The Scientific Consensus on Climate Change as a Gateway Belief
PLOS ONE | DOI:10.1371/journal.pone.0118489 February 25, 2015 3/8
Procedure and Materials
Subjects were asked to provide an estimate (0%–100%) of the perceived level of scientific con-
sensus on human-caused climate change at both the beginning (pre-test) and at the end of the
survey (post-test). Respondents also answered a number of questions about whether they think
climate change is happening, human-caused, how worried they are about climate change and
whether they think people should be doing more or less about the issue. An overview of the key
belief measures used in this study is also provided in Table 1. All the consensus messages tested
led to significant gains in public understanding of the scientific consensus compared to the
control group. The current study, however, analyzes the data for an entirely different purpose.
This study investigates whether the effect-size of the treatment messages (i.e., the change in re-
spondents’estimates of the scientific consensus) is causally associated with a pre-post change
in the belief that climate change is happening, human-caused and a worrisome problem that
requires greater societal support. To test our hypotheses, all experimental consensus-message
interventions were collapsed into a single “treatment”category and subsequently compared to
the “control”group. The conceptual structure of the GBM (Fig. 1) is assessed using a structural
equation modeling (SEM) approach.
Results
The path (mediation) model was estimated using STATA’s (StataCorp) SEM software. As
recommended by Preacher and Hayes [21], significance of effects and model parameters was
assessed using bias-corrected and accelerated bootstrap confidence intervals (the data were re-
sampled 1,000 times). Furthermore, according to Little’s MCAR test, part of the data (approx.
8% of the sample) was missing, but not completely at random. As a result, the model was esti-
mated using a Full Information Maximum Likelihood (FIML) procedure [22] and adjusted for
important covariates, including gender, education, age and political party. Using commonly
Fig 2. Visual depiction of the Gateway Belief Model (GBM) results.
doi:10.1371/journal.pone.0118489.g002
The Scientific Consensus on Climate Change as a Gateway Belief
PLOS ONE | DOI:10.1371/journal.pone.0118489 February 25, 2015 4/8
accepted criteria for model evaluation [23], the fit of the overall model structure is considered ac-
ceptable; χ
2
(6) = 27.38, p<0.01, χ
2
/ df = 4.56, CFI = 0.92, RMSEA = 0.06 (90% CI: 0.04–0.08).
On average, being in one of the treatment groups (vs. the control group) significantly increases
respondents’estimate of the scientific consensus (by 12.80%). Moreover, a change in a respon-
dent’s estimate of the scientific consensus significantly influences the belief that climate change
is happening, human-caused, and the extent to which they worry about the issue (note that belief
in climate change and human causation also directly influence level of “worry”). Changes in
these factors, in turn, significantly predict support for public action on climate change. As hy-
pothesized, the effect of the treatment (i.e. increased belief in the scientific consensus) on the
expressed need for public action is fully mediated by the intervening variables (i.e., key beliefs
about climate change). Similarly, the effect of the treatment on the key-belief measures is fully
mediated by perceived scientific agreement.
While the model “controls”for the effect of political party, we also explicitly tested an alter-
native model specification that included an interaction-effect between the consensus-treat-
ments and political party identification. Because the interaction term did not significantly
improve model fit (nor change the significance of the coefficients), it was not represented in
the final model (to preserve parsimony). Yet, it is important to note that the interaction itself
was positive and significant (β= 3.25, SE = 0.88, t= 3.68, p<0.001); suggesting that compared
to Democrats, Republican subjects responded particularly well to the scientific consensus mes-
sage. A visual depiction of the results is provided in Fig. 2 and a detailed overview of the effect
sizes and model parameters is provided in Table 2.
Table 2. SEM model parameters.
Model path relationships B S.E. 95% C.I.
bca
Treatment !PSA 12.8 2.13 8.60, 17.0
PSA !Belief in CC 0.12 0.03 0.06, 0.16
PSA !Belief in HC 0.15 0.02 0.11, 0.19
PSA !Worry 0.07 0.02 0.03, 0.10
Belief in CC !Worry 0.07 0.02 0.02, 0.11
Belief in HC !Worry 0.13 0.03 0.07, 0.19
Belief in CC !Public Action 0.08 0.02 0.04, 0.12
Belief in HC !Public Action 0.08 0.03 0.02, 0.14
Worry !Public Action 0.19 0.03 0.13, 0.25
Note: Numbers are rounded. N= 1104. Covariates; age, gender, education and political party. PSA =
Perceived Scientific Agreement; CC = Climate Change; HC = Human Causation; B; unstandardized
regression coefficient, SE: standard error, 95%CI
bca
: Bias-corrected and accelerated bootstrap confidence
interval (based on 1,000 bootstrap samples).
doi:10.1371/journal.pone.0118489.t002
The Scientific Consensus on Climate Change as a Gateway Belief
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Discussion
Previous research has suggested that perceptions of the scientific consensus play an important
role in the formation of public beliefs and attitudes towards climate change and, moreover,
that (mis)perceptions of the scientific consensus potentially decrease public support for climate
change policies [15–19]. This study constructively builds upon and extends this research by
providing direct experimental evidence for the “gateway belief model”(GBM). Using pre and
post measures from a national message test experiment, we found that all stated hypotheses
were confirmed; increasing public perceptions of the scientific consensus causes a significant
increase in the belief that climate change is (a) happening, (b) human-caused and (c) a worri-
some problem. In turn, changes in these key beliefs lead to increased support for public action.
In sum, these findings provide the strongest evidence to date that public understanding of the
scientific consensus is consequential.
It is important to note that the gateway belief model (GBM) describes a two-step cascading
effect. First, the effect of consensus messaging on key beliefs about climate change is fully medi-
ated by the perceived level of scientific agreement. Second, the effect of the induced increase in
perceived scientific consensus is fully mediated onto support for public action via the key be-
liefs about climate change. In other words, belief in the scientific consensus functions as an ini-
tial “gateway”to changes in key beliefs about climate change, which in turn, influence support
for public action. Thus, consistent with other recent research, this study found that when in
doubt about scientific facts, people are likely to use consensus among domain experts as a heu-
ristic to guide their beliefs and behavior [15].
These findings have important practical implications for science communication and stand
in direct juxtaposition to the claim that “consensus-messaging”is not effective as a communi-
cation strategy [13,14]. In particular, it is sometimes argued that (a) despite past public com-
munication efforts, public understanding of the scientific consensus has not changed much in
the last decade and hence the approach must not be very effective (i.e., “the stasis argument”)
[13] and (b) because people are predisposed to engage in protective motivated reasoning (i.e.,
people process information consistent with their ideological worldviews), consensus-messaging
is likely to be unsuccessful or could even backfire [12,14].
The present study finds no support for these claims. On the contrary, results of this study
show that perceived scientific consensus acts as a key gateway belief for both Democrats and
Republicans. In fact, the consensus message had a larger influence on Republican respondents.
It should be noted that this interaction might, to some extent, be attributable to a ceiling effect
(i.e., there is relatively less upward adjustment potential in perceived scientific consensus for
Democrats, although a significant gap in understanding persists even among Democrats). We
do not dispute, however, that some people—especially those with strong ideological responses
to the issue—selectively process information or engage in motivated reasoning [9,14]. Yet, we
find that consensus-messaging does not increase political polarization on the issue (perhaps
partly due to the neutral scientific character of the message) and shifts the opinions of both
Democrats and Republicans in directions consistent with the conclusions of climate science.
Furthermore, other recent research [24] has suggested that past campaigns have been un-
successful (in both their reach and exposure), given that a substantial lack of awareness of the
scientific consensus still persists (“information deficit”) while at the same time, the spread of
misinformation has vastly increased (“misinformation surplus”). Because people often encoun-
ter multiple and conflicting informational cues, the criticism might be raised that as a con-
trolled experiment, this study may overstate the actual effect that consensus messaging would
have in the real-world. While we agree with this view and see this as an important and open
area for future research, this shortcoming does not, however, negate the structural validity of
The Scientific Consensus on Climate Change as a Gateway Belief
PLOS ONE | DOI:10.1371/journal.pone.0118489 February 25, 2015 6/8
the GBM’s causal mechanisms. It is also important to note that this study only used a single
treatment, yet found that even a single, simple description of the scientific consensus signifi-
cantly shifted public perceptions of the consensus and subsequent climate change beliefs and
desire for action. A concerted campaign to inform the public about the scientific consensus
would ideally involve numerous exposures to the key message, conveyed by a variety of trusted
messengers [6,20].
This is important because by strategically sowing seeds of doubt, organized opponents of cli-
mate change action have continually tried to undermine the validity of the scientific consensus
argument [11]. As this research shows, such attempts could potentially decrease public engage-
ment with climate change. Nonetheless, the present research also indicates the potential effica-
cy of consensus-messaging campaigns in mitigating such skepticism, as well as in generating
support for public action on climate change. Particularly, repeated exposure to simple messages
that correctly state the actual scientific consensus on human-caused climate change is a strate-
gy likely to help counter the concerted efforts to misinform the public. Effectively communicat-
ing the scientific consensus can also help move the issue of climate change forward on the
public policy agenda [6][15][20][24–25].
Supporting Information
S1 File.
(PDF)
Author Contributions
Conceived and designed the experiments: SLV AAL GDF EWM. Performed the experiments:
SLV AAL GDF. Analyzed the data: SLV. Wrote the paper: SLV AAL GDF EWM.
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