File:Prevalence of selected contrarian sub-claims in conservative think tank communication over time.webp

English: "This figure illustrates the temporal variation (quarterly) in the proportion of sub-claims found in CTT documents related to (a) “Climate policies are harmful”, “Clean energy won’t work”, and (b) “Climate movement is unreliable”, “Climate science is unreliable”. Highlighted periods in the time series include: (A) 2003 Climate Stewardship Act; (B, C) 2005 and 2007 Climate Stewardship and Innovation Acts; (D) Climate Security Act of 2007; (E) American Clean Energy and Security Act; (F) Clean Power Plan; (G-I) An Inconvenient Truth and Al Gore Nobel/IPCC Prize; (J) “Climategate”; and (K) Peter Gleick/Heartland Institute affair. Note that darker lines represent cubic splines used to aid interpretation."

"Next, given the considerable attention paid to CTT discourse in the literature on organized climate contrarianism14,15,22,24,31,32, we offer a more detailed examination of the specific claims of these organizations over two decades. Figure 3a examines the dynamics of two prominent policy-related sub-claims—“Climate policies are harmful” and “Clean energy won’t work”—while also overlaying major US climate policy events, from the 2003 Climate Stewardship Act to the Obama administration’s Clean Power Plan. The highlighted sections of Fig. 3a indicate the relevant beginning and ending dates for these efforts, with the most common being the introduction of and voting on a Congressional bill. The figure demonstrates that claims on the harmful effects of climate policy, particularly for the economy, closely align with changes in the US policy environment: CTTs tend to first ramp up discussion following the announcement of a bill, and then again prior to a bill reaching the floor for a vote. Particularly salient is the spike in policy claims in late 2009, which not only coincided with intense debate on the American Clean Energy and Security Act (ACES), but also with the COP15 climate summit in Copenhagen. This summit was billed as an especially consequential meeting for progressing mitigation policies. Claims that challenge the efficacy of clean energy, however, appear less sensitive to policy events and yet have increased considerably over time, with the second quarter of 2020 representing the highest share of these claims to date. Notably, this trend runs counter to the plummeting cost of renewable energy production33."

"Figure 3b similarly displays the dynamics of the two leading science-related claims: “Climate movement is unreliable” and “Climate science is unreliable”. Consistent with qualitative accounts of the “denial machine”34, in the early 2000s CTTs continued to “manufacture uncertainty”24 surrounding scientific evidence on anthropogenic global warming, including questioning the validity of climate models and data. However, while challenging scientific models, data, and the consensus remains a common rhetorical strategy even today (roughly 10% of claims), our data highlight a clear transition in 2005 towards accusations of alarmism, bias, hypocrisy, conspiracy, and corruption against climate scientists, advocates, the media, and politicians. A steady upward trend in these types of claims is seen throughout the George W. Bush administration, with an initial peak between 2006 and 2007. This period was a watershed moment for climate advocacy with the release of An Inconvenient Truth and its subsequent Academy Award, the awarding of the Nobel Peace Prize to Al Gore and the IPCC, as well as the publication of a landmark report by the Union of Concerned Scientists criticizing the climate contrarian countermovement. However, the series does not peak again until the so-called “Climategate” controversy in late 2009 (timed to occur a short time before the COP15 summit presumably to undermine climate negotiations) and early 201035, with a smaller subsequent spike in late 2011 following strong reactions to the release of Heartland Institute internal documents by the climate scientist Peter Gleick36. While this series has not returned to Climategate-era levels, the “Climate movement is unreliable” category remains a central motif of CTT climate-related messaging."