Download Do scientists agree about climate change? public perceptions from a

Carsey
New eNglaNd
CarseyInstItute
Issue BrIef No. 22
summer 2010
I n s t I t u t e
DoscientistsagreeaboutClimateChange?
PublicPerceptionsfromanewHampshiresurvey
L aw r e n c e c . H a m i Lt o n
anewsurveyInitiative
Human-causedclimatechangehasadualidentityasamajor
topicforscientificresearchandadivisivepoliticalwedge
issueamongthepublic.Whileresearchacrossmanydisciplineshasbuiltastrongconsensusamongscientists,surveys
havemappedoutdeepeningdivisionsinpublicopinion.1
However,thewordingofsurveyquestionsoftenconformsto
popularratherthanscientificconcepts,makingcomparisons
betweenpublicandscientificviewslessclear-cut.survey
questionsmightbevaguelyworded,forexample,oraskordinarypeoplequestionsthateventopscientistscannotanswer,
suchaspersonalconsequencesoffutureclimatechange.
CarseyInstituteresearchers,workingwiththeuniversity
ofnewHampshire(unH)surveyCenterandtheuniversity
Officeofsustainability,recentlybegananewinitiativetrackingpublicperceptionsaboutclimatechangeastheychange
overtime.aseriesofregionalsurveysdesignedforother
purposesnowincludesasetofthreequestionsaboutclimate
change.unlikequestionsonsomeearliersurveys,thequestionsinunH’snewsurveyinitiativefocusonthecentral
pointstatedbyscientistsinawiderangeofscientificreports:
whatishappeningnow—notsometimeinthefuture—due
toclimatechange.Theneutralandfactualwordingofthe
questionsfocusesonwhatpeopleknow,orbelievethey
know,aboutclimatechangenow.
Thefirstsurveytookplaceinapril2010aspartofnew
Hampshire’sGranitestatePoll.alongwithotherquestions
onpoliticalcandidatesandbackgroundfactors,astatewide
sampleof512residentswasaskedhowwelltheyunderstand
theissueofglobalwarmingorclimatechange,whether
theythinkmostscientistsagreethatitishappeningnow
andcausedbyhumans,andwhattheypersonallybelieve.
OurnewHampshirepollwillberepeatedquarterly,with
thenextwaveinsummer2010.Continuingresultshereand
KeyFindings
In April 2010, the Granite state Poll included three new
questions about climate change on its survey of 512
New Hampshire residents. Key findings are as follows:
•
•
•
•
•
•
slightly more than half the respondents believe
they understand “a moderate amount” about
climate change or global warming. Twenty-nine
percent believe they understand “a great deal.”
understanding tends to increase with education.
About half think that most scientists agree climate
change is happening now, caused mainly by
human activities. On the other hand, 41 percent
think there is little agreement among scientists.
similarly, about half personally believe that
climate change is happening and is human
caused. Thirty-nine percent believe it is
happening but with natural causes. Only 4
percent believe that climate change is not
happening.
most of those with college or postgraduate
education believe that climate change is
happening now, caused by humans, and that
scientists agree on this point.
sharp polarization exists. While a large majority
of Democrats believe that climate change
is happening and is human caused, most
republicans believe it is a natural phenomenon.
Three-fourths of Democrats but only one-fourth
of republicans think that most scientists agree.
There is a strong correlation between personal
beliefs and perceptions about the scientific
consensus.
1
2
CarseyInstItute
elsewhereshouldprovidea“thermometer”trackingpublic
viewsofclimatechangescience,almostinrealtime.This
collaborativesurveyresearchispartofunH’scommitment
tointegratingsustainabilitythroughoutitscurricula,operations,research,andengagementefforts.2
HowMuchDoyouunderstand?
Thefirstofthreeclimatechangequestionsinourtelephone
interviewsaskedrespondentstoratetheirownunderstanding:
next,Iwouldliketoaskyousomequestionsaboutthe
issueofglobalwarmingorclimatechange.Howmuch
doyoufeelyouunderstandaboutthisissue—would
yousayagreatdeal,amoderateamount,onlyalittle,or
nothingatall?
4
agreatdeal
3
amoderateamount
2
Onlyalittle
1
Don’tknow/nothingatall
Mostrespondentsexpressedconfidenceintheirunderstandingofthesecomplexissues(seeFigure1).Fifty-three
percentfelttheyunderstood“amoderateamount”about
globalwarmingorclimatechange,andtwenty-ninepercent
saidtheyunderstood“agreatdeal.”relativelyfewadmitted
tounderstanding“onlyalittle”(16percent)or“nothingat
all”(2percent).Marginsoferrorfortheoverallpercentages
inFigures1,3,and5shouldbewithin+or–5percent.
Figure1.Howmuchdoyouunderstandabout
climatechange?
Nothing
16
Moderate
53
Great deal
0
29
10
20
30
Weighted percent
40
Figure2.Howmuchunderstandingaboutclimate
change,byeducation
High school or less
Nothing
Technical/some college
Nothing
5
Little
Little
26
Moderate
19
Moderate
42
Great deal
2
50
Great deal
27
29
College graduate
Nothing
Postgraduate
Nothing 0
1
Little
Little
13
Moderate
59
Great deal
0
Moderate
54
Great deal
26
20
8
40
60
0
37
20
40
60
Weighted percent
Doscientistsagree?
2
Little
topicssuchasthegreenhouseeffect,atmosphericchemistry,andpastclimatechangeinvolvetechnicalknowledge
outsidemostpeople’sexperience.Wefoundthatrespondents
withhighereducationtendedtohaveevengreaterconfidenceintheirunderstanding.eighty-fourpercentofcollege
graduatesandninety-onepercentofthosewithpostgraduatedegreessaidtheyunderstood“amoderateamount”or“a
greatdeal”aboutclimatechange(seeFigure2).
50
Claimsthatscientistsdonotagreeaboutclimatechange
havebeenwidelyrepeatedbynon-scientists.Injournalsand
meetingswherescientistsaddresstheirpeers,onedoesindeedseelivelydiscussionandcompetinghypothesesregardingtopicssuchastheimpactsofclimatechangeonbehavior
oficesheets,oceancurrents,andstorms.Behindtheunsettledfrontiers,however,standsabroadconsensusonmore
fundamentalfacts.Thereislittledisagreementamongactive
scientiststhatconcentrationsofcarbondioxide(CO2)and
othergreenhousegasesaffecttheearth’sclimate,thatthese
concentrationsarerapidlyincreasingduetohumanactivities
andarealreadyreachinglevelsnotseeninhundredsofthousandsofyears,thatmanyindicatorsshowclimateunevenly
butclearlywarmingnowasaresult,andthatfuturechanges
inthisdirectionpresentrisksforcoastalcities,agriculture,
andotheraspectsofcivilization.Theconsensusbuildson
studiesrangingfrombasicphysicstoindicatorsofancient
climates,satellitemeasurements,andocean-atmosphere
models.suchresearchhasbeenconductedbyscientists
acrossmanydifferentdisciplines,workingwithmanykinds
ofdatainmanydifferentcountries.
CarseyInstItute
Consensusviewsbasedonthisbodyofresearchhavebeen
articulatedthroughindividualandjointstatementsbyallof
themajoru.s.scientificorganizationswithrelevantexpertise,3instatementsorreportsbythenationalacademiesof
thirteenleadingscientificnations,4andinbroadinternationalreviewsofresearchresults.7asurveyofmorethan
3,000earthscientistsfoundthat90percentagreedthatmean
globaltemperatureshavegenerallyrisencomparedwith
pre-1880slevels.eighty-twopercentagreedhumanactivities
areasignificantcontributingfactortotemperaturechange.
amongactiveclimateresearchersansweringthesurvey,
morethan96percentagreedonbothitems.6anopenletter
totheu.s.CongressinOctober2009noted,“Observations
throughouttheworldmakeitclearthatclimatechangeis
occurring,andrigorousscientificresearchdemonstrates
thatthegreenhousegasesemittedbyhumanactivitiesare
theprimarydriver.”Thisletterwassignedbythepresidents
ordirectorsofeighteenscientificorganizations,including
theamericanassociationfortheadvancementofscience,
theamericanGeophysicalunion,theamericanMeteorologicalsociety,andtheamericanstatisticalassociation.
similarpointsweremadeinaMay2010lettersignedby255
membersofthenationalacademyofsciencespublished
intheleadingjournalscience:“Theplanetiswarmingdue
toincreasedconcentrationsofheat-trappinggasesinour
atmosphere...Mostoftheincreaseintheconcentrationof
thesegasesoverthelastcenturyisduetohumanactivities,
especiallytheburningoffossilfuelsanddeforestation.”7
Wedesignedthesecondquestiononourpublicopinion
surveytomatchthecentralpointmadeinallofthesestatementsbyscientists:
Whichofthefollowingtwostatementsdoyouthinkis
moreaccurate?
3
Mostscientistsagreethatclimatechangeis
happeningnow,causedmainlybyhuman
activities.
2
Thereislittleagreementamongscientists
whetherclimatechangeishappeningnow,
causedmainlybyhumanactivities.
1
Don’tknow/noanswer
Inhalftheinterviews,“mostscientistsagree”wasthe
firstchoicereadbytheinterviewer;intheotherhalf,“there
islittleagreement”wasreadfirst.resultsfromthetwo
formsarecombinedinouranalysisheretooffsetpossible
response-orderbias.abouthalftherespondents(49percent)
understandthatmostscientistsagreechangeishappening
now,causedmainlybyhumanactivities.alargeminority
(41percent),however,believetheretobelittleagreement
amongscientists(seeFigure3).
Figure3.Doscientistsagreeitishappeningnow,
causedbyhumans?
Don’t know/
no answer
9
Little agreement
41
Most agree
49
0
10
20
30
40
Weighted percent
50
awarenessofthescientificconsensusvariessharplywith
respondenteducation,asgraphedinFigure4.Fifty-four
percentofcollegegraduatesandfifty-ninepercentwith
postgraduatedegreesthinkthatmostscientistsagree.respondentswithahighschooleducationorless,ortechnical
school/somecollege,moreoftenbelievethatthereislittle
agreementamongscientists.
Figure4.Doscientistsagreeitishappeningnow,
byeducation
High school or less
Don’t know/
no answer
Technical/some college
Don’t know/
no answer
12
Little agreement
Little agreement
46
Most agree
13
49
Most agree
42
38
College graduate
Don’t know/
no answer
Postgraduate
Don’t know/
no answer
6
Little agreement
Little agreement
41
Most agree
54
0
20
40
8
60
32
Most agree
0
Weighted percent
59
20
40
60
3
4
CarseyInstItute
WhatDoyouPersonally
Believe?
Figure6.Whatdoyoubelieve,byeducation
High school or less
Don’t know/
no answer
Wealsoaskedrespondentswhattheypersonallybelieve
aboutclimatechange:
Not now
Whichofthefollowingthreestatementsdoyoupersonallybelieve?
4
Climatechangeishappeningnow,caused
mainlybyhumanactivities.
3
Climatechangeishappeningnowbut
causedmainlybynaturalforces.
2
Climatechangeisnothappeningnow.
1
Don’tknow/noanswer
similartothesciencequestion,wealternatedtheinterviewscriptssothat“happeningnow,causedmainlybyhumanactivities”wasreadfirsthalfthetime,and“nothappeningnow”wasreadfirstintheothers.Wealsoalternatedthe
sequenceofthescienceandpersonalopinionquestions,so
eachcamefirsthalfthetime.Overall,51percentchosethe
“now/human”response(seeFigure5).
Figure5.Whatdoyoupersonallybelieve?
Don’t know/
no answer
Not now
6
4
Now/natural
39
Now/human
0
51
10
20
30
Weighted percent
40
50
ThepatternsofpersonalbeliefsseeninFigure5resemble
scientificagreementresultsinFigure3.Likeotherquestionsonoursurvey,personalbeliefsvarywitheducation
(seeFigure6).Majoritiesofthosewithcollegeorpostgraduatedegreesthinkchangeishumancausedandhappeningnow.Thosewithoutcollegedegreesmoreoftencredit
naturalcauses.
Technical/some college
Don’t know/
no answer
8
6
Not now
6
Now/natural
Now/human
4
Now/natural
49
49
Now/human
37
42
College graduate
Postgraduate
Don’t know/
no answer
4
Don’t know/
no answer
Not now
4
Not now
Now/natural
Now/natural
36
Now/human
20
40
24
Now/human
55
0
9
4
60
63
0
20
40
60
Weighted percent
PolarizedViewsofscience
BreakdownsinFigures2,4,and6drawattentiontothe
influenceofeducationonwhatpeoplebelieveaboutclimate
change.Giventhepolarizednatureofpoliticaldiscourseon
thistopic,itcameasnosurprisetoseethatpoliticalorientationmattersevenmorethaneducation.Figure7depictsthe
relationshipbetweenpoliticalpartyidentification(Democrat,Independent,orrepublican)andpersonalbeliefsabout
climatechange.aboutthree-quartersoftheDemocrats,
comparedwithonlyone-quarterofrepublicans,believethat
climatechangeishappeningnow,causedmainlybyhumans.
Mostrepublicansbelievethatclimatechangeishappening
nowbutcausedbynaturalforces.Independentsfitbetween
theseextremes,withapluralityaccepting“now/human.”
Figure7.Whatdoyoubelieve,bypoliticalparty
identification
Democrat
Don’t know/
no answer
Independent
4
Not now 0
Now/natural
Don’t know/
no answer
8
Not now
7
Now/natural
20
Now/human
75
37
Now/human
48
0
Republican
Don’t know/
no answer
8
Not now
8
Now/natural
59
Now/human
0
26
20
40
60
80
Weighted percent
20
40
60
80
CarseyInstItute
apoliticalbreakdownregardingagreementamongscientistsyieldssimilarresults(seeFigure8).Three-quartersof
Democratsbutonlyonequarterofrepublicansthinkthat
mostscientistsagreethatclimatechangeishappeningnow,
causedbyhumans.Mostrepublicansbelieveinsteadthat
thereislittleagreementamongscientists.Independentssplit
almostevenlybetweenthetwochoices.
Figure8.Doscientistsagreeitishappeningnow,
bypoliticalpartyidentification
Democrat
Don’t know
no answer
Independent
Don’t know
no answer
5
Little agreement
20
Most agree
10
Little agreement
46
Most agree
44
75
0
20
40
60
80
Republican
Don’t know
no answer
13
Little agreement
63
Most agree
25
0
20
40
60
80
Weighted percent
Ofcourse,respondents’personalbeliefsandtheirperceptionsofwhatscientistsbelieveturnouttobecloselyrelated
(seeFigure9).Thosewhobelievethattheclimateischangingnow,duetohumancauses,overwhelmingly(82percent)
thinkthatmostscientistsagreewiththem.Byalmostas
greatamargin,74percentofthosewhobelievethatcurrentclimatechangehasnaturalcauses,orthatclimateisnot
changing,thinkthatthereislittleagreementamongscientistsonthispoint.
Figure9.Doscientistsagree,bywhatyoubelieve
Don’t know/
no answer
Don’t know/no answer
44
Little agreement
35
Most agree
20
Don’t know/no answer
Not now
22
Little agreement
74
Most agree
5
Don’t know/no answer
Now/natural
9
Little agreement
74
Most agree
17
Don’t know/no answer
Now/human
4
Little agreement
14
Most agree
82
0
20
40
Weighted percent
60
80
Discussion
Onissuessuchastherealityofclimatechange,scientists
mightwishthepublicwouldlooktothemforexplanations
ofresearchresultsandthenformtheirownopinions.In
practice,however,mostofthepublichasnocontactwith
theresearchjournalsandprofessionalmeetingsofscientists.scientists’effortstocommunicatemoredirectlywith
thepublicfacecompetitionfromothervoices,oftenmore
familiartolayaudiences,makingconflictingclaimsabout
science.Highereducationclearlyplaysarole,visibleinthis
surveyandothers.8Beyondtheirschoolyears,however,
mostpeopleacquireinformationaboutscienceindirectly
fromnon-scientists,suchasjournalists,politicalcommentators,activists,orbloggers.Theseintermediatesourceshave
limitationsintheirowncomprehensionandmayholdstrong
biasesaboutwhattotransmit.Moreover,inthisnew-media
agepeopleincreasinglychoosetoacquireandretaininformationfromsourcesthatsupporttheirownprejudices,9so
contraryinformationbecomessystematicallyfilteredout.as
aresult,peoplewhohaveneverreadorlistenedtoclimate
scientistscanneverthelessbelievetheyunderstandthescientists’researchfairlywellandholdstrongopinionsaboutthe
validityofthisresearch.
Improvedscienceliteracyamongjournalistswouldbevaluable,althoughnewsmediaexperiencingfinancialpressures
sometimesfeelthatreportersdedicatedtosciencearealuxury
theycannolongerafford.Onepromisingdevelopmenthas
beenthegrowingengagementofleadingresearchersinscienceblogs,whichaimtomakestate-of-the-artscientificideas
anddiscussionsaccessibletoamuchbroaderaudience.10Their
effortsmighthelptocounterbalance,atleastpartly,someof
theconfusionspreadbyless-informedsources.
scientificknowledgeaboutclimatechangehasadvanced
substantiallyinthefewyearssincetheIntergovernmental
PanelonClimateChangepublisheditsFourthassessment
report(2007).11However,whilescientificunderstandingadvanced,understandingbytheu.s.publicseemedto
marchintheoppositedirection.severalrecentpollsfound
significantdeclinesintheproportionofamericanswho
believeclimatechangeishappeningoriscausedmostlyby
humans.12Thesedeclinesfollowed“Climategate,”thetheft
inthefallof2009ofemailsfromtheClimateresearchunit
attheuniversityofeastangliaandasnowy2010winter
inpartsoftheunitedstates.13Whiletheirdatashowthat
globalwarmingcontinues,manyscientistsareencountering
aseverelypolarizedpublicresponse.
OurnewHampshirepollwillberepeatedquarterly,with
thenextwaveinthesummerof2010.Continuingresultswill
provideapublicopinion“thermometer,”trackingperceptionsaboutclimatechangescience,almostinrealtime.
5
6
CarseyInstItute
endnotes
1.r.e.Dunlapanda.M.McCright,“aWideningGap:
republicanandDemocraticViewsonClimateChange,”
Environmentseptember/October2008,http://www.
environmentmagazine.org/archives/Back%20Issues/
september-October%202008/dunlap-full.html;M.C.nisbet
andt.Myers,“twentyyearsofPublicOpinionaboutGlobal
Warming,”Public Opinion Quarterly71(3)(2007):444–470.
2.unHhasearnedseveralawardsforitssustainability
initiatives,whichrangefromtheoldestendowed
sustainabilityprograminu.s.highereducationtoleading
policyresearchonvulnerablechildren,youth,andfamilies
andsustainablecommunitydevelopment.Discover
thesustainablelearningcommunityatunHatwww.
sustainableunh.unh.edu,www.carseyinstitute.unh.edu,and
www.discoversustainability.org.
3.n.Oreskes,“ThescientificConsensusonClimate
Change,”Science306(5702)(2004):1686.
4.G8+5,“G8+5nationalacademies’Jointstatement:
ClimateChangeandthetransformationofenergy
technologiestoaLowCarbonFuture,”nationalacademies
ofBrazil,Canada,China,France,Germany,India,Italy,
Japan,Mexico,russia,southafrica,theunitedKingdom,
andtheunitedstates,http://www.nationalacademies.org/
includes/G8+5energy-climate09.pdf;nationalresearch
Council,advancingthescienceofClimateChange
(Washington,DC:nationalresearchCouncilofthe
nationalacademies,2010).
5.IntergovernmentalPanelonClimateChange,Climate
Change2007—ThePhysicalscienceBasis,Contribution
ofWorkingGroupItotheFourthassessmentreport
oftheIntergovernmentalPanelonClimateChange
(Cambridge:CambridgeuniversityPress,2007);K.
richardsonetal.,Synthesis Report from Climate Change:
Global Risks, Challenges & Decisions(Denmark:university
ofCopenhagen,2009),http://www.pik-potsdam.de/news/
press-releases/files/synthesis-report-web.pdf.
6.P.t.DoranandM.K.Zimmerman,“Directexamination
ofthescientificConsensusonClimateChange,”EOS90(3)
(2009):22–23.
7.P.H.Gleicketal.,“ClimateChangeandtheIntegrityof
science,”Science 328(5979)(2010):689–690.
8.L.C.HamiltonandB.D.Keim,“regionalVariationin
PerceptionsaboutClimateChange,”International Journal
of Climatology29(15)(2009):2348–2352;L.C.Hamilton,
“WhoCaresaboutPolarregions?resultsFromasurveyof
u.s.PublicOpinion,”Arctic, Antarctic, and Alpine Research
40(4)(2008):671–678.
9.M.a.Baumandt.Groeling,“newMediaandthe
PolarizationofamericanPoliticalDiscourse,”Political
Communication25(2008):345–365;D.M.Kahanetal.,
“ThesecondnationalriskandCulturestudy:Makingsense
of—andMakingProgressin—theamericanCultureWar
ofFact,”(Washington,DC:GeorgeWashingtonuniversity
researchPaperno.370,2007).
10.Forexample,seehttp://www.realclimate.org.
11.Foranupdatecoveringnewerresearchsincethe2007
IPCCreport,seeK.richardson,Synthesis Report.
12.GallupPoll,“america’sGlobalWarmingConcerns
ContinuetoDrop,”http://www.gallup.com/poll/126560/
americans-Global-Warming-Concerns-ContinueDrop.aspx;a.Leiserowitz,e.Mailbach,andC.roserrenouf,“ClimateChangeintheamericanMind:
americans’GlobalWarmingBeliefsandattitudesin
January2010,”(newHaven,Ct:yaleProjectonClimate
Change,2010),http://environment.yale.edu/uploads/
americansGlobalWarmingBeliefs2010.pdf;Incontrast,
anotherrecentsurveyemphasizedpublicsupportforaction
onclimatechange,despitedivisionsonwhetherwarming
hasmostlyhumancauses:stanforduniversity,“Global
warmingpoll,”(ProducedbyGFK,2010)http://woods.
stanford.edu/docs/surveys/Global-Warming-surveyselected-results-June2010.pdf.
13.althoughtheClimateresearchunitscientistswere
widelycriticizedinnewsmediaandblogsbasedon
excerptsfromtheseemails,twocarefulinquiriesfound
noevidenceofwrongdoing:thescienceandtechnology
Committeeoftheu.K.HouseofCommons(seehttp://
www.realclimate.org/docs/387.pdf)andanindependent
appraisalbytheOxburghreportcommissionedbythe
universityofeastanglia(seehttp://news.sciencemag.org/
scienceinsider/2010/04/oxburgh-report-clears-controvers.
html);Forrecentupdatesontemperaturetrends,seehttp://
data.giss.nasa.gov/gistemp/.
CarseyInstItute
acknowledgments
DavidMooreattheCarseyInstituteadvisedonquestion
designandsuggestedtheresponse-orderexperiments.
supportfromtheunHOfficeofsustainabilityandthe
CarseyInstituteenabledthisseriesofsurveys.sampling
andinterviewsweredonebytheunHsurveyCenterin
connectionwithitsGranitestatePoll.
abouttheauthor
LawrenceC.HamiltonisaprofessorofsociologyattheuniversityofnewHampshireandaseniorfellowattheCarsey
Institute([email protected]).
7
8
CarseyInstItute
since1997,theuniversityOfficeofsustainability—theoldest
endowedsustainabilityprograminhighereducationinthe
unitedstates—hasbeentransformingunHintoasustainable
learningcommunityacrosscurriculum,operations,research
andengagement,andinitiativesinbiodiversity,climate,food,
andculture.
www.sustainableunh.unh.edu
Buildingknowledgeforfamiliesandcommunities
TheCarseyInstituteconductspolicyresearchonvulnerable
children,youth,andfamiliesandonsustainablecommunity
development.Wegivepolicymakersandpractitionerstimely,
independentresourcestoeffectchangeintheircommunities.
ThisworkwassupportedbytheCarseyInstituteendowment
andtheuniversityOfficeofsustainability.
HuddlestonHall
73Mainstreet
Durham,nH03824
(603)862-2821
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