Climate change risk perception in the USA and alignment with sustainable travel behaviours

question asking them to select their level of concern regarding climate change. Environmental and societal beliefs were measured by two statements from The New Environmental Paradigm (Humans have the right to modify the natural environment to suit their needs and There are lim- its to growth beyond which our industrialized society cannot expand) [45]. Demographic infor- mation was collected through multiple choice questions. Lastly an open-ended question was used to explore participants’ perceptions of future travel. It did not define travel, providing freedom for participants to interpret the questions. Data collection and analysis Data (S1 Table) were collected through an online survey (S1 File) hosted by SurveyMonekyTM on 19–20 October, 2016. Participants were recruited through SurveyMonkeyTM with instruc- tions to recruit at least 1000 participants with an even gender split. The survey required partici- pants to give their informed consent before proceeding to the questionnaire. To be eligible, participants needed to be at least 18 years old and living in the USA. A total of 1143 people completed the survey. Responses were eliminated if participants did not answer the question which investigated attitudes towards optimism, technology and environmental beliefs (n = 72). Therefore, the total number of responses analysed was 1071. The study was approved by the Human Research Ethics Committee at the University of Otago (Ref: D15/393). All quantitative data were analysed using SPSSTM version 24. Descriptive statistics were

used to determine how participants answered the multiple choice and Likert scale questions while relationships between variables were identified through Spearman’s correlations. We used hierarchical multiple regressions to test our models. Participants were asked to rank seven global threats, with one being the threat they were most concerned about and seven as being the threat they were least concerned about. Not all participants ranked all seven threats. It was assumed that unranked global threats represented a lack of concern. In an attempt to capture this lack of concern without skewing the rankings, these values were flipped during the analysis so that the threat that was most concerning was given a value of seven and the least concerning threat was given a value of one. Similarly, although both positive and negative statements were asked, all statements were converted into a positive framing for analysing and presenting the data. Thematic coding was used to identify patterns within the open-ended question asking par- ticipants to describe their perceptions of future travel [46]. Representative words or phrases (ie code) were assigned to each response [47]. To increase validity and replicability of the results, a coding manual was designed (S2 Table) and intercoder reliability was calculated. The lowest percent agreement between the two coders was 92% and the lowest Krippendorff’s α was 0.732 suggesting there was a high level of consensus and replicability regarding the results [48]. A

single response could contain multiple codes; for example: the quote “High speed rail. Hope- fully more mass transit, fewer cars. More safe walking/biking paths” would be coded under shift because it refers to shifting to alternate modes of transportation (mass transport, walking and biking) as well as improve as it is assumed that references to faster trains or high-speed rail are referencing new technology such as Maglev trains (S2 Table). Participant demographics Of the 1071 respondents, 52% (n = 557) identified as female, 46% (n = 491) identified as male and the remaining 2% identified as other (n = 8), preferred not to say (n = 9) or did not answer the questions (n = 6; S1 Fig). All age groups had at least 150 participants (S1 Fig). Participants aged 60 and over made up the largest age group (25%) while the least represented age group was between the ages of 40–49 (16%). Participants came from a wide variety of educational PLOS ONE Climate change risk perception in the USA and alignment with sustainable travel behaviours PLOS ONE | https://doi.org/10.1371/journal.pone.0244545 February 3, 2021 6 / 17