Public Understanding of Climate Science, Extreme Weather and Climate Attribution
Creators: name: Dryden, Rachel
Publisher: name: Carnegie Mellon University
Year: 2019
Subjects: subject: 160510 Public Policy
subject: FOS: Political science
subject: FOS: Political science

description: Experts in the geophysics community have understood the role of greenhouse gases in shaping the earth's climate for over a century and have grown increasingly confident and concerned about the risks of climate change. Studies conducted since the early 1990s have observed several changes in public understanding of the causes and consequences of climate change. The aim of this thesis is to explore public understanding and perceptions of various aspects of climate science, climate change, and its impacts. This work provides an update on the climate change perceptions literature, identifying new and persistent knowledge gaps, as well as characterizing the belief-driven undercurrent that consistently predicts support for immediate climate action across my studies.<br>In Chapter 2, I employ a local mail-out survey and a national online survey to explore the extent to which people understand the important differences between common air pollution and carbon dioxide (CO2). This work focuses especially on the very different atmospheric residence times of both—and what drives public support to abate climate change now. I find that people do not understand this fundamental difference, dramatically underestimate how long CO2 remains in the atmosphere and continues to change the climate, and the policy implications of long-lived CO2 in the atmosphere. However, this misunderstanding does not deter respondents from showing strong support for immediate climate action.<br>While Chapter 2 focuses on drivers of climate change, in Chapter 3, I evaluate public perceptions of one of the most salient impacts of climate change: an increase in the frequency of extreme weather. In a two-part study comprised of a convenience sample of face-to-face interviews followed by a national study, I assess when, and to what extent, laypeople attribute extreme events to climate change and whether and how their beliefs are predictive of their decision thresholds, sensitivities, and support for immediate climate action using signal detection theory. I find that prior climate change beliefs are significant drivers that influence how people make decisions in attributing extreme events to climate change and in their self-reported support for immediate action in response to climate risks. I also find that simple spinner boards are effective tools in communicating non-stationary processes, such as attribution, to laypeople.<br>In Chapter 4, I focus on public perceptions of what can be done on the part of individuals to reduce CO2 emissions and how laypeople view the efficacy of individual versus collective actions in a two-part study, starting with a convenience sample of face-to-face interviews and followed by a national study. I find that respondents believe that individuals have higher response-efficacy than what is likely to be attainable from individual actions alone, i.e. apart from any broader societal or governmental action. However, respondents view individual and governmental actions as having the same response-efficacy.<br>Finally, Chapter 5 discusses this work’s contribution to the literature and the implications for the development of risk communications revealed in Chapters 2 through 4. Findings in all chapters show strong support for immediate action against climate risks. Climate change beliefs are significant predictors for decision thresholds and sensitivities in identifying hurricane frequencies as evidence of climate change (Chapter 2) and for support for immediate climate action across my studies (Chapters 2 and 3). These, and other findings reported in the thesis, can inform—and offer opportunities for—the development of improved risk communications, as well as alternative decision-making strategies when it comes to long-term risks and educational interventions.