Toward a unified understanding of climate anxiety: Examining measures of climate and eco-anxiety

PLOS One | https://doi.org/10.1371/journal.pone.0339562 December 29, 2025 13 / 19 climate anxiety factor. The correlation between the climate anxiety factor and self-efficacy to show individual emission- reducing behavior was also small. For criterion validity, the climate anxiety factor was not correlated with the general readiness factor or with the specific factors of individual behavior and policy acceptance. However, we observed a strong correlation with the specific readi- ness factor of political participation. Discussion This study examined the validity of climate and eco-anxiety by testing competing measurement models for two existing scales: the Climate Anxiety Scale [6] and the Hogg Eco-Anxiety Scale [12]. By testing joint models, we assessed the overlap between both constructs and identified a jangle fallacy. Our findings showed that the best-fitting and most parsi- monious solution was an overarching model with a general climate anxiety factor, indicated by one CAS and four HEAS factors. This suggests that existing scales, such as the CAS and HEAS, seem to measure the same overarching con- struct, presumably climate anxiety as we discuss below. We also highlight additional limitations in the measurement of climate and eco-anxiety and propose ways to improve assessment of this important topic. The first key finding is that most participants in this non-clinical, general adult population sample reported low levels of climate and eco-anxiety, resulting in floor effects. The fact that most people in the general population are not heavily

affected by climate anxiety, meaning they do not report highly impairing anxiety accompanied by symptoms that inter- fere drastically with everyday life, is in line with most other studies using the scales (CAS [6,9,22,27,29] and HEAS [7,12,24,37]). Given that climate anxiety is partly defined by clinically relevant emotional and functional impairments and has been studied exclusively in general populations, these findings are not surprising. However, this limits knowledge about the validity of the construct. The floor effect of climate and eco-anxiety in the general population is a form of variance restriction that can substan- tially lower correlations estimated for investigations of convergent or criterion validity. Furthermore, floor effects can intro- duce spurious interactions [61], which must be considered when interpreting experimental work. Since floor effects occur when scale items fail to differentiate between individuals due to uniformly low responses, a promising approach could be to distinguish between affective climate-anxious experiences (including appraisals) and their potential impairments in psychological functioning [62]. Wullenkord and colleagues [62] found that climate-anxious affect and appraisal, which gen- erally have a higher occurrence probability, exhibit greater variability in the general population—an essential condition to avoid variance restrictions. In contrast, impairment is likely to manifest primarily in vulnerable or clinically affected groups,

suggesting that future work should evaluate impairment separately and include such populations in validation efforts. Second, our comparison of different measurement models for the Climate Anxiety Scale and the Hogg Eco-Anxiety Scale addresses the varying ways in which these scales have been used in previous research (e.g., as one-factor solu- tions, as separate but correlated factors, or as different factors compared to the original version). Examining the overlap between climate and eco-anxiety measures, we found that a joint higher-order model—with a single general factor—pro- vided the best fit for the data. This suggests that treating climate and eco-anxiety as distinct constructs constitutes a jangle fallacy, as both scales appear to measure the same overarching construct, which we would describe as climate anxiety. This interpretation may be debated. On the one hand, theoretical considerations suggest that eco-anxiety encom- passes a broader construct than climate anxiety [12,63], which might support labeling the factor as eco-anxiety. However, our model reveals a substantial overlap between CAS and HEAS, and we want to emphasize the possibility that the joint model nevertheless mostly measures anxiety related to climate change. This consideration originates from closely inspecting the HEAS, which consists of several symptoms. In relation to these symptoms, other environmental threats are mentioned explicitly only in one item and in the scale’s introduction: “Over the last 2 weeks, how often have you

been bothered by the following problems when thinking about climate change and other global environmental conditions