Scientific Consensus on Manmade Global Warming: Think Tank Influence on Public Opinion Through News Media
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Rowan University Rowan Digital Works Theses and Dissertations 10-28-2008 Scientific consensus on manmade global warming: think tank influence on public opinion through news media Greg Howe Rowan University Follow this and additional works at: https://rdw.rowan.edu/etd Part of the Public Relations and Advertising Commons Recommended Citation Howe, Greg, "Scientific consensus on manmade global warming: think tank influence on public opinion through news media" (2008). Theses and Dissertations. 695. https://rdw.rowan.edu/etd/695 This Thesis is brought to you for free and open access by Rowan Digital Works. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of Rowan Digital Works. For more information, please contact [email protected]. SCIENTIFIC CONSENSUS ON MANMADE GLOBAL WARMING: THINK TANK INFLUENCE ON PUBLIC OPINION THROUGH NEWS MEDIA by Greg Howe A THESIS Submitted in partial fulfillment of the requirements of the Master of Arts Degree of The Graduate School at Rowan University October 28, 2008 Approved by____ ____ D ate approved © 2008 Greg Howe ABSTRACT Greg Howe Scientific Consensus on Manmade Global Warming: Think Tank Influence on Public Opinion through News Media 2008 Advisor: Joseph Basso, J.D., Ph. D., APR Public Relations Graduate Program This study examined the influence of think tanks, in the news media, on public opinion of what most scientists believe about the cause of global warming. The researcher performed a content analysis on two national newspapers spanning May through July, 2006, the three months surrounding the U.S. release of An Inconvenient Truth, to determine whether papers of differing political ideology provided different amounts of context concerning the global warming scientific consensus. The data were tabulated using Microsoft Excel. Experimental research was also conducted using 103 undergraduate Rowan University public relations and public relations and advertising majors to determine if articles with less context caused confusion in subjects regarding their perception of the scientific consensus on manmade global warming. The findings showed that think tanks were used as experts only sparingly. However, articles claiming that global warming is a natural phenomenon were found to provide less context than articles claiming that global warming is manmade. The experimental research showed that subjects were most uncertain about global warming after reading an article with very little context. MINI-ABSTRACT Greg Howe Scientific Consensus on Manmade Global Warming: Think Tank Influence on Public Opinion through News Media 2008 Advisor: Joseph Basso, J.D., Ph. D., APR Public Relations Graduate Program This study examined the influence of think tanks, in the news media, on public opinion of what most scientists believe about the cause of global warming. The researcher performed a content analysis to gather information on amounts of context provided on the scientific consensus on manmade global warming in two newspapers of differing political ideology. Experimental research was also conducted to determine the affects of context on understanding of the consensus. The findings showed that the newspaper favoring the scientific consensus on manmade global warming contained more context than the newspaper opposing it. The experimental research showed that subjects receiving more context were more certain about a scientific consensus on global warming then those receiving little context. Table of Contents List of Figuresv CHAPTER PAGE I. Introduction 1 Statement of the Problem 3 Purpose of the Study 4 Definition of Terms 5 Hypotheses and Research Questions 7 The Assumptions 8 The Limitations 9 Significance of the Study 9 II. Review of the Literature 10 Global Warming Explanation and Early Research 10 Development of a Scientific Consensus 13 Public Perceptions Existence of Global Warming 18 Scientific Consensus on Existence of Global Warming 18 Existence of Manmade Global Warming 19 Scientific Uncertainty & the Media Science Communication 19 Climate System Dynamics 20 Journalistic Objectivity 20 ii Context 21 Journalist Ignorance 22 Journalists' Power to Validate 22 Framing 23 Two-Step Flow Theory of Media Effects 24 The Claimsmakers Issues Management 25 Carbon Industry 27 Think Tanks 31 Tactics 32 Manipulation 35 Think Tanks in Context 35 III. Research Design 37 Instruments Content Analysis 37 Experimental Research 39 Procedures Content Analysis 40 Experimental Research 41 Data Analysis 42 IV. Results 43 Content Analysis 43 Experimental Research 47 iii V. Interpretation and Suggestions 54 Evaluation 54 Interpretation 54 Content Analysis 54 Experimental Research 60 Conclusions 63 Contribution to the Field 64 Further Research 65 REFERENCES 67 APPENDICES Appendix A: Content Analysis - Coding Sheet 75 Appendix B: Experimental Research- Pre-Test Survey 79 Appendix C: Experimental Research - Skeptic Article (Washington Times - 11/14/04) 83 Appendix D: Experimental Research- Context Article (Washington Post- 11/9/04) 85 Appendix E: Experimental Research- Post-Test Survey 87 iv List of Figures FIGURE PAGE Figure 1 Natural and enhanced greenhouse effects 11 "The greenhouse effect keeps the earth warm and habitable; without it, the earth's surface would be about 60 degrees Fahrenheit colder on average. [T]he enhanced greenhouse effect means even more of the sun's heat is trapped, causing global temperatures to rise" (Pew Center on Global Climate Change-a, p.2). Figure 2 "Keeling Curve" 12 Series measurements of atmospheric carbon dioxide taken at Mauna Loa Observatory, Hawaii. The data confirmed that the increased accumulation of carbon dioxide produced by burning fossil fuels and other industrial products, contributed to the greenhouse effect (Scripps CO2 Program, 2007). Figure 3 Atmospheric CO 2 concentrations over past 420 thousand years 13 The Mauna Loa record placed in the context of the variations in CO 2 over the past 420,000 years, based on reconstructions from polar ice cores. During ice ages, the CO 2 levels were around 200 parts per million (ppm), and during the warmer interglacial periods, the levels were around 280 ppm. The levels in 2005 were around 378 ppm (Scripps CO2 Program, 2007). Figure 4 Global and continental temperature change 17 "Comparison of observed continental- and global-scale changes in surface temperature with results simulated by climate models using natural and anthropogenic forcings. Decadal averages of observations are shown for the period 1906 to 2005 (black line) plotted against the centre of the decade and relative to the corresponding average for 1901-1950. Lines are dashed where spatial coverage is less than 50%. Blue shaded bands show the 5-95% range for 19 simulations from five climate models using only the natural forcings due to solar activity and volcanoes. Red shaded bands show the 5-95% range for 58 simulations from 14 climate models using both natural and anthropogenic forcings" (IPCC, 2007-a, p.11). Figure 5 Author affiliation 55 Figures 6 & 7 Scientist citations 56 Figure 8 Government official citations 56 Figure 9 Government official belief citations 57 Figure 10 Advocate citations 57 Figure 11 Think tank associate citations 58 Figure 12 Research document citations 58 Figure 13 Al Gore and An Inconvenient Truth citations 59 Figure 14 Relative scientific acceptance of global warming view citations 59 Figure 15 Article tone 60 Figure 16 Respondents' beliefs 61 Figure 17: Most scientists' beliefs 61 Figure 18 Skeptic article treatment 62 Figure 19 Control article treatment 63 Figures 20 & 21 Citation percentages and totals 64 vi Chapter I Introduction "Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations" (IPCC, 2007a, p.1 0). This statement from working group I of the most recent assessment report by the United Nations' Intergovernmental Panel on Climate Change reveals the international scientific consensus view that manmade emissions are very likely, or 90 percent certain, to be the cause of global warming. On whether or not global warming exists, the IPCC goes on to state that "[w]arming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level" (p.5). The report notes that 11 of the last 12 "years (1995-2006) rank among the 12 warmest years in the instrumental record of global surface temperature (the average of near-surface air temperature over land and sea surface temperature) since 1850" (p.5). As for future impacts, "[c]ontinued greenhouse gas emissions at or above current rates would cause further warming and induce many changes in the global climate system th during the 2 1st century that would very likely be larger than those observed during the 20 century" (p.13). The National Academy of Sciences, when asked by the Bush administration to prepare a document answering questions on climate change science, agreed that "[g]reenhouse gases are accumulating in Earth's atmosphere as a result of human activities, causing surface air temperatures and subsurface ocean temperatures to rise" (p.1), and that the IPCC's 2001 report "accurately reflects the current thinking of the scientific community on this issue" (National Research Council, 2001, p.3). A 2004 content analysis of 928 articles with the words climate change in their abstracts published in refereed scientific journals between 1993 and 2003 reinforced the consensus claim: none of the papers disagreed with the consensus view on global warming (Oreskes, 2004). Despite the solidification of a scientific consensus over the last twenty-plus years, a public consensus has yet to emerge. In 2006, between 35 and 65 percent of the American public agreed that a scientific consensus existed on whether or not global warming is even happening. When asked if "a lot of disagreement exists among scientists," respondents agreed 62, 67, 64 and 56 percent of the time in 1997, 1998, 2006 and 2007, respectively (Nisbet & Myers, 2007, pp.4 5 1, 452).