The review, published in the journal Trends in Psychology, was conducted by Nicolas de Oliveira Cardoso, Thaiane Moreira de Oliveira, Luisa Massarani, Ketlin da Rosa Tagliapietra, and Wagner de Lara Machado, researchers affiliated with Federal Fluminense University, the Oswaldo Cruz Foundation, and the Pontifical Catholic University of Rio Grande do Sul. The team searched seven databases and applied the Cochrane risk-of-bias tool for randomized trials, known as RoB-2, to each of the twelve studies that met their inclusion criteria. RoB-2 is the current gold standard for evaluating whether the results of a randomized trial can be trusted, examining domains such as the randomization process, deviations from intended interventions, missing outcome data, measurement of outcomes, and selective reporting. Using it in the context of climate communication research is relatively unusual, and that is precisely what makes the review notable.

The trials the reviewers examined represent the leading edge of belief-change research. Several tested psychological inoculation, a strategy in which people are pre-exposed to weakened forms of misleading arguments so they can recognize and resist them later. Work by researchers such as Sander van der Linden and colleagues has suggested that inoculation messages can confer resistance to climate misinformation, and a 2024 study in Nature Human Behaviour tested inoculation strategies across twelve countries. Other trials in the review focused on correcting misinformation after exposure, comparing different correction formats and placements, including on social media platforms such as Instagram. Still others examined whether communicating the overwhelming scientific consensus on climate change—through plain facts, visual displays, or metaphors—could shift beliefs, building on the influential idea that perceived consensus acts as a gateway belief.

What the reviewers found was not that these ideas are wrong in principle, but that the evidence base supporting them is far shakier than the field’s enthusiasm would suggest. All but one of the twelve randomized trials received a judgment of some concern or high risk of bias under RoB-2. In practical terms, this means that for nearly every study, there were credible methodological reasons to doubt whether the reported effects reflected the true impact of the intervention. The reviewers highlight two biases as particularly prevalent: selection bias and instrumentation bias. Selection bias arises when the way participants are recruited or allocated produces groups that differ before the intervention even begins, so any observed difference in climate beliefs may stem from those pre-existing differences rather than from the message itself. Instrumentation bias, meanwhile, occurs when the measurement tools used to assess outcomes are flawed, unstable, or poorly adapted, distorting the apparent size of change between pre-test and post-test.

The connection between these biases and the field’s underwhelming results is more than coincidental, the authors argue. When trials are methodologically fragile, effects tend to shrink or vanish under more rigorous scrutiny, and the predominance of interventions with small or no effects may partly be a symptom of the biases themselves rather than a pure reflection of how malleable climate beliefs really are. This reframing matters. A pessimistic reading of the literature would conclude that people’s climate beliefs are simply resistant to change. The review suggests a more nuanced interpretation: the true effectiveness of belief interventions cannot yet be established with confidence, because the studies designed to measure that effectiveness are themselves compromised.

The reviewers also point to a striking geographic imbalance. The included studies came overwhelmingly from high-income countries, with the United States dominating the sample. This matters for generalizability. Climate beliefs are shaped by political systems, media environments, cultural values, and direct experience of environmental change, all of which vary enormously across contexts. An inoculation message calibrated for American audiences steeped in polarized media discourse may behave very differently in Brazil, India, or Nigeria, where the drivers of skepticism or concern about climate change can be entirely different. The authors call for future randomized trials to evaluate interventions in low- and middle-income populations, a gap they describe as essential if the field wants its findings to speak to the global public rather than a narrow slice of it.

On the measurement side, the review offers a constructive lead. The authors identified four psychometrically sound instruments for measuring climate change beliefs, tools that have undergone proper validation procedures for reliability and validity. Adopting such instruments, they argue, is essential for reducing instrumentation bias in future trials. The broader point echoes long-standing principles from psychometric theory: an intervention study is only as credible as the scale used to detect change. If a questionnaire’s wording, response alternatives, or scoring shift in meaning between measurement points, or if it was never validated in the population being studied, then apparent pre-test to post-test gains may be artifacts rather than genuine belief change. Research on question wording effects in climate surveys has shown how sensitive these measures can be, making the choice of instrument a first-order methodological decision rather than an afterthought.

To tackle selection bias, the reviewers recommend pre-test/post-test designs combined with clearly established cut-off points for climate belief levels. The logic is familiar from classic experimental design: measuring participants before randomization allows researchers to verify that groups are comparable at baseline and to adjust statistically for any residual differences, while predefined thresholds for what counts as a given belief level reduce researcher discretion in interpreting outcomes. The authors also sketch a forward-looking agenda, outlining directions for the design of future randomized controlled trials and for meta-analyses that would synthesize the evidence more rigorously. Their hope is that integrating these recommendations—better designs, better instruments, broader populations—could improve both the accuracy and the generalizability of the next generation of climate belief interventions.

The stakes of this methodological reckoning are considerable. Climate change is already producing measurable harms to physical and mental health, and the scientific consensus on its human causes is essentially complete. Yet public belief lags, sustained in part by organized disinformation and conspiracy narratives, which meta-analytic work has linked to reduced willingness to engage in climate-friendly behavior and political action. If the research community cannot demonstrate, with trials that survive bias assessment, which communication strategies actually work, then practitioners, educators, and policymakers are left choosing among interventions on the basis of weak evidence. The review does not claim that inoculation, consensus messaging, or debunking are useless; it claims something more unsettling—that the field does not yet know, because the trials testing them are too fragile to say.

There is, ultimately, a constructive message embedded in this critical one. The fact that eleven of twelve trials raised concerns is a sign of a young, fast-moving field that has prioritized creative ideas over methodological armor. The RoB-2 framework, validated measurement instruments, pre-registered designs with baseline measurement, and deliberate attention to underrepresented populations are all available tools; what the review demands is that they be used systematically. If future trials meet that standard, the field will finally be able to distinguish between interventions that genuinely move climate beliefs and those that merely looked effective in flawed studies. For a problem as urgent as climate change, knowing the difference may be one of the most valuable contributions psychology can make.

Subject of Research: Effectiveness and risk of bias in randomized controlled trials of interventions to change climate change beliefs

Article Title: Limited Impact of Interventions for Climate Belief: A Systematic Review Assessing Risk of Bias

Article References: de Oliveira Cardoso, N., de Oliveira, T. M., Massarani, L., da Rosa Tagliapietra, K., & de Lara Machado, W. (2025). Limited Impact of Interventions for Climate Belief: A Systematic Review Assessing Risk of Bias. Trends in Psychology. https://doi.org/10.1007/s43076-025-00485-5

Image Credits: AI Generated

DOI: 10.1007/s43076-025-00485-5

Keywords: climate change beliefs, systematic review, risk of bias, randomized controlled trials, psychological inoculation, misinformation, scientific consensus, environmental psychology, selection bias, instrumentation bias, psychometrics, climate communication