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Blowin' in the wind: Short-term weather and belief in Blowin' in the wind: Short-term weather and belief in
anthropogenic climate change. anthropogenic climate change.
Lawrence C. Hamilton
University of New Hampshire
, lawrence.hamilton@unh.edu
Mary D. Stampone
University of New Hampshire
, mary.stampone@unh.edu
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Hamilton, L.C., Stampone, M.D. Blowin' in the wind: Short-term weather and belief in anthropogenic
climate change. (2013) Weather, Climate, and Society, 5 (2), pp. 112-119.
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Blowin’ in the Wind: Short-Term Weather and Belief in Anthropogenic Climate Change
LAWRENCE C. HAMILTON
Department of Sociology, University of New Hampshire, Durham, New Hampshire
MARY D. STAMPONE
Department of Geography, University of New Hampshire, Durham, New Hampshire
(Manuscript received 28 September 2012, in final form 2 January 2013)
ABSTRACT
A series of polls provides new tests for how weather influences public beliefs about climate change.
Statewide data from 5000 random-sample telephone interviews conducted on 99 days over 2.5 yr (2010–12)
are merged with temperature and precipitation indicators derived from U.S. Historical Climatology Network
(USHCN) station records. The surveys carry a question designed around scientific consensus statements that
climate change is happening now, caused mainly by human activities. Alternatively, respondents can state that
climate change is not happening, or that it is happening but mainly for natural reasons. Belief that humans are
changing the climate is predicted by temperature anomalies on the interview day and the previous day,
controlling for season, survey, and individual characteristics. Temperature effects concentrate among one
subgroup, however: individuals who identify themselves as independent, rather than aligned with a political
party. Interviewed on unseasonably warm days, independents tend to agree with the scientific consensus
regarding anthropogenic climate change. On unseasonably cool days, they tend not to agree. Although
temperature effects are sharpest for just a 2-day window, positive effects are seen for longer windows as well.
As future climate change shifts the distribution of anomalies and extremes, this will first affect beliefs among
unaligned voters.
1. Introduction
While the evidence-based scientific consensus that
humans are changing Earth’s climate has strengthened
in recent years, acceptance of this idea among the U.S.
public has not followed suit. Instead, there have been
fluctuations without clear trend in overall levels of ac-
ceptance. The surface calm masks deepening partisan
division (McCright and Dunlap 2011). Survey analysis
finds that political outlook dominates other character-
istics in predicting individual beliefs about climate. Even
education and science literacy have divergent effects,
depending on politics (Hamilton 2008, 2011b, 2012;
Hamilton et al. 2012; Kahan et al. 2011a,b; McCright
2011; McCright and Dunlap 2011). Among self-identified
Democrats o r liberals, higher education and science
literacy are associated with greater concern regarding
anthropogenic climate change. Among Republicans or
conservatives, education and science literacy have weak
or even negative effects. Among unaligned respondents,
both climate change beliefs and the effects of education
or science literacy fall between these partisan extremes.
Scientists, political figures, journalists, and bloggers
offer the public competing interpretations of observed
changes such as the decline of Arctic sea ice (Notz and
Marotzke 2012), global temperature and sea level rise
(Rahmstorf et al. 2012), and the frequency and severity
of climate extremes such as droughts and heat waves
(Trenberth and Fasullo 2012). These interpretations,
including true and false facts, often are differentially
accepted by people according to their preexisting beliefs—
a process called biased assimilation (Lord et al. 1979;
Munro and Ditto 199 7; Corner et al. 2012; Hamilton
2012). Personal recollections of climat e or weather
events could be filtered in a similar fashion, and inter-
preted differently in accord with more general beliefs
(Goebbert et al. 2012). Trivial personal experiences such
as ambient temperature, thirst, and visual cues can affect
responses to climate questions as well (Joireman et al.
Corresponding author address: Lawrence Hamilton, Department
of Sociology, University of New Hampshire, 20 Academic Way,
Durham, NH 03824.
E-mail: lawrence.hamilton@unh.edu
112 WEATHER, CLIMATE, AND SOCIETY VOLUME 5
DOI: 10.1175/WCAS-D-12-00048.1
Ó 2013 American Meteorological Society
2010; Lewandowski et al. 2012; Li et al. 2011; Risen and
Critcher 2011), further evidence that scientific and po-
litical arguments are not the only forces affecting public
beliefs.
Recently, survey researchers have tested whether
objectively measured climate or weather influence cli-
mate beliefs. Analyzing data from diverse rural areas,
Hamilton and Keim (2009) found that perceived local
impacts of climate change were highest in snow-country
regions with winter warming trends. Shao (2012) found
associations between decadal temperature trends and
public concern about global warming. Akerlof et al.
(2013) report associations between personal experience
(to some degree objectively confirmed) and perceptions
of global warming risks. Goebbert et al. (2012) exam-
ined relationships between self-reports of temperature,
drought, or flood experience and corresponding objec-
tive long-term indicators. Controlling for ideology and
worldview, their temperature-comparison indicator had
little effect on perceived temperature experience. Ob-
jective flood and drought-comparison indicators, how-
ever, exhibit stronger effects on perceptions. Egan and
Mullin (2012) tested for effects of temperature anoma-
lies on nationally representative surveys. They found
a significant effect of daily temperature on expressed
beliefs about the evidence for global warming (not
necessarily anthropogenic). This effect appears short
lived for normal temperature variations, being strongest
when just a 2-day window before the interview is con-
sidered. Exceptional heat waves have longer-lasting ef-
fects. Political identity and education moderate the
temperature effects.
In the analysis that follows, we test for weather effects
on agreement with the scientific-consensus view of climate
change. We find impacts from temperature generally con-
sistent with earlier studies, but they place into sharp focus
the question of whose beliefs change with the weather.
2. The Granite State Poll
Four times each year, the Granite State Poll conducts
telephone interviews with random samples of about 500
New Hampshire (NH) residents. This poll achieves prom-
inence during New Hampshire’s presidential primaries
and other elections. It employs standard, well-validated
techniques for obtaining representative samples of the
state’s adult population. Probability weights permit
minor ad justments for design and samp ling bias—the
latter, from comparison with census data. Typical Granite
State Poll questions cover political and opinion topics;
several climate questions were added to the mix be-
ginning in April 2010 (Hamilton 2010). By July 2012,
climate questions had been carried on 10 survey cycles,
involvingmorethan5000interviews on 99 separate dates. A
national Carsey Institute survey in 2011 [National Com-
munity and Environme nt in Rural America (NCERA)]
asked the same climate questions and obtained results
similar to those from New Hampshire (Hamilton 2011a,
2012). The quarterly New Hampshire data, however,
provide a high-quality and uniquely resolved time series.
Table 1 describes variables in our analysis. For com-
parison, we show both statewide and national results on
the climate questions. One response to the personal belief
question, ‘‘Climate change is happening now, caused
mainly by human activities,’’ corresponds to the main
point of statements and reports on climate change from
leading science organizations (Oreskes 2004), national
academies of science (G815 2009; NRC 2010), reviews of
research results (Solomon et al. 2007; Richardson et al.
2009), and surveys of scientists (Doran and Zimmerman
2009). Similar statements containing the same elements
as our survey question have been made by many science
organizations (e.g., AMS 2012). No leading science or-
ganization takes a position of disagreement that human
activities are now changing the Earth’s climate. Tele-
phone interviewers rotated the order in which responses
were read to avoid possible bias. Fifty-three percent of
New Hampshire respondents, and 52% nationwide, chose
the now/human response to this question.
Background characteristics in Table 1 are the chief
predictors identified by previous research (McCright
and Dunlap 2011; Hamilton 2012). Our respondents
could describe their politics on a seven-point scale from
1 5 ‘‘strong Democrat’’ to 7 5 ‘‘strong Republican,’’
with 4 5 ‘‘independent’’ being the middle category
(about 2%, set aside here, chose ‘‘other’’ or declined to
answer). In keeping with the common poll finding that
people who say they are ‘‘independent but leaning’’
toward one party behave as partisans in practice, we
grouped the 1–3 categories as Democrats and the 5–7
categories as Republicans; only the neutral 4 category is
counted here as independents (about 900 people or 18%
of the estimation sample).
On 10 surveys from April 2010 to July 2012, the
now/human response to our belief question fluctuated
from 49% to 57%, without trend. Some fluctuations no
doubt reflect sampling variation. Some could reflect un-
measured factors such as current events. If we adjust for
respondent characteristics, for season, and for survey-
to-survey fluctuations caused by unmeasured factors, are
there detectable weather effects in these data?
3. New Hampshire weather data
Our focus on one relatively small state simplifies
the integration of survey with weather data. Daily
APRIL 2013 H A M I L T O N E T A L . 113
temperature and precipitation observations repre-
senting the weather across New Hampshire were obtained
from the U.S. Historical Climatology Network (USHCN,
http://cdiac.ornl.gov/ep ubs/ndp/ushcn/ushcn.html). The
USHCN archive contains quality controlled records
from a select group of high-quality, long-term weather
stations that are adjusted for systematic biases (Menne
et al. 2009). New Hampshire has five geographically
dispersed USHCN stations that represent daily weather
characteristics at relevant scales for temperature and
regional circulation (Legates and Willmott 1990; Vinnikov
et al. 2011).
Although all weather variables were considered, daily
precipitation is difficult to quantify on a statewide basis
because of the influences of terrain and season on the
distribution of liquid and frozen precipitation. In New
Hampshire, precipitation varies greatly in amount and
type over short distances within the same regional
weather pattern due to factors such as elevation and
proximity to the coast. This leads to large differences
among daily precipitation totals across the five USHCN
stations. Daily snowfall amount and the depth of snow
on the ground are only relevant for surveys conducted
during the snow season. Whether for measurement or
for substantive reasons, the precipitation indicators we
extracted (based on total precipitation or alternatively,
occurrence of 1-inch events) show no relation to climate
beliefs.
Spatial patterns in minimum and maximum temper-
ature are more consistent at regional scales than any
measure of precipitation (Vinnikov et al. 2011). Al-
though absolute temperatures from individual New
Hampshire stations differ, daily departures due to re-
gional weather patterns strongly correlate between sta-
tions. One principal component captures 84% of the
variance over our study period. Following Keim et al.
(2003) we use the statewide mean of USHCN temper-
ature anomalies as our regional index.
Table 1 describes two of the weather variables we
extracted from station records and integrated with the
dated survey data. Temp2 is average temperature
anomaly for the interview and one day prior. This 2-day
window gives the best overall fit in predicting climate
beliefs, although we also tested many other windows.
TABLE 1. Variable definitions with summaries. NH survey summaries are probability-weighted means or percentages based on non-
missing values (n 5 4897). Weighted percentages from a U.S. nationwide survey conducted in August 2011 (n 5 2006) are given for
comparison on the two climate questions (NCERA; see Hamilton 2012).
Climate questions
Understand—Next, I would like to ask you some questions about the issue of global warming or climate change. How much do you feel
you understand about this issue ... would you say a great deal, a moderate amount, only a little, or nothing at all? (Coding reversed for
analysis, so higher values denote greater understanding.)
A great deal (NH 25; U.S. 22)
A moderate amount (NH 53; U.S. 50)
Only a little (NH 18; U.S. 23)
Nothing at all/NA (NH 4; U.S. 5)
Belief—Which of the following three statements do you personally believe? (Order rotated at random.)
Climate change is happening now, caused mainly by human activities (NH 53; U.S. 52)
Climate change is happening now, but caused mainly by natural forces (NH 36; U.S. 39)
Climate change is NOT happening now (NH 5; U.S. 5)
Don’t know/NA (NH 5; U.S. 4)
Respondent background characteristics
Age—What is your current age? (mean 55 yr, std dev 16, range 18–96)
Gender—Male (49) or female (51)
Education—What is the highest grade of education you completed and got credit for?
High school or less (21)
Technical school or some college (22)
College graduate (34)
Postgraduate work (23)
Party—GENERALLY SPEAKING, do you usually think of yourself as a Republican, a Democrat, an Independent or what?
Democrat (42)
Independent (18)
Republican (40)
Weather indicators
Temp—New Hampshire USHCN stations mean daily temperature anomaly relative to 1981–2010 normals. For 1 Jan 2010–23 Jul 2012,
1-day mean 1.358C, std dev 4.068C, range 12.268–168C.
Temp2—New Hampshire USHCN stations mean temperature anomaly on interview and 1 previous day. For the 99 interview days, 2-day
mean 1.328C, std dev 3.608C, range 5.628–11.968C.
114 WEATHER, CLIMATE, AND SOCIETY VOLUME 5
Fig. 1 visualizes our time series. The upper curve tracks
statewide temperature anomaly. The lower spike plot
counts interviews on each date, across 10 surveys and
more than 5000 interviews on 99 separate days.
4. Climate beliefs and temperature
Does short-term weather influence acceptance of the
central point found in climate change statements by
scientists? Table 2 shows results from three logit re-
gression models. The dependent variable for each is a
(0,1) indicator of whether people believe that climate
change is happening now, caused mainly by human activ-
ities. Previous studies establish that age, gender, education,
self-assessed understanding, and po litical orientation pre-
dict a wide range of climate-related beliefs. These are in-
cluded as possible predictors in all three models. Odds
ratios describe the multiplicative effects of a one-unit in-
crease in each predictor on the odds of expressing a
now/human belief. All background variables show sta-
tistically significant effects, in directions expected from
previous research. Odds of a now/human response de-
crease with respondent age, are higher for women than
men, increase with education and with self-assessed
understanding, and are lower among Republicans than
among independents and Democrats.
Model 1 is the base version, with season, two-day
temperature anomaly, and the main effects of each
background variable as predictors. Season exhibits no
net effects. Unseasonably warm or cool temperatures on
the interview day and the previous day, however, sig-
nificantly shift the odds of believing that humans are
changing the climate (p 5 0.023).
Model 2 adds two complications. First, it incorporates
party–education interaction terms in keeping with ear-
lier studies. We find significant effect s (p , 0.0005) in
the expected direction: education raises the odds of
agreeing with the scientific consensus among Demo-
crats, does so more weakly among independents, and not
at all among Republicans. Second, model 2 incorporates
analogous party– temperature interaction terms. For
independents only, the interaction proves highly sig-
nificant (p , 0.0005)—indicating that temperature has
a substantial effect for independents but not for people
aligned with either party. Other models, not shown,
tested for similar interactions between temperature
and other background variables: age, gender, educa-
tion, and understanding. Unlike party–temperature,
these interactions proved weak and not significant. For
parsimony and better precision, we omit them from the
models of Table 2.
Model 3, a mixed-effects version of model 2, allows
random intercepts to capture possible survey-to-survey
variation that is not explained by variables in the model.
Survey-to-survey variation could reflect unmeasured
events such as political or economic developments,
FIG. 1. Timelines of NH daily temperature index (mean deviation from 1981 to 2010 station
normals) and the Granite State Poll: about 5000 telephone interviews in 10 surveys, spread over
99 separate days from April 2010 to July 2012.
A
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