Replication Data for: Current Surveys May Underestimate Climate Change Skepticism Evidence from List Experiments in Germany and the USA

Strong public support is a prerequisite for ambitious and thus costly climate change mitigation policy, and strong public concern over climate change is a prerequisite for policy support. Why, then, do most public opinion surveys indicate rather high levels of concern and rather strong policy support, while de facto mitigation efforts in most countries remain far from ambitious? One possibility is that survey measures for public concern fail to fully reveal the true attitudes of citizens due to social desirability bias. In this paper, we implemented list-experiments in representative surveys in Germany and the United States (N = 3620 and 3640 respectively) to assess such potential bias. We find evidence that people systematically misreport, that is, understate their disbelief in human caused climate change. This misreporting is particularly strong amongst politically relevant subgroups. Individuals in the top 20% of the income distribution in the United States and supporters of conservative parties in Germany exhibit significantly higher climate change skepticism according to the list experiment, relative to conventional measures. While this does not definitively mean that climate skepticism is a widespread phenomenon in these countries, it does suggest that future research should reconsider how climate change concern is measured, and what subgroups of the population are more susceptible to misreporting and why. Our findings imply that public support for ambitious climate policy may be weaker than existing survey research suggests.

有力的公众支持是制定雄心勃勃且成本高昂的气候变化减缓政策的先决条件，而公众对气候变化的高度关切则是获取政策支持的必要前提。那么，为何多数民意调查显示公众关切程度与政策支持力度均处于较高水平，而大多数国家的实际气候减缓行动却远未达到雄心勃勃的标准？一种可能性是，由于社会期望偏差（social desirability bias），针对公众关切度的调查测量无法完全揭示公民的真实态度。本文中，我们分别在德国与美国的代表性抽样调查中开展了列表实验（list-experiment），以评估此类潜在偏差，两国样本量分别为3620与3640。我们发现存在系统性误报的证据：即受访者会系统性地低报自身对人为导致的气候变化（human-caused climate change）的怀疑态度。此类误报在与政治相关的人口亚群体中尤为显著。相较于传统测量方式，根据列表实验的结果，美国收入分布前20%的群体以及德国保守党派支持者，展现出明显更高的气候变化怀疑论（climate skepticism）倾向。尽管这并不足以确凿证明气候变化怀疑论在两国中普遍存在，但它确实表明，未来研究应重新审视气候变化关切度的测量方式，以及哪些人口亚群体更易出现误报行为及其背后的原因。本研究结果显示，公众对雄心勃勃的气候政策的支持力度，或许比现有调查研究得出的结论更低。