European public support for climate mitigation measures is resilient to uncertainty information

Public acceptance is a critical factor for the successful implementation of climate mitigation measures. Yet, Integrated Assessment Models (IAMs) often exclude this social dimension and risk misjudging the real-world viability of the mitigation measures they are designed to model. This study examines how informed perceptions of feasibility-related uncertainties affect acceptance, support, and affect in the general population towards four IAM-modelled measures: bioenergy with carbon capture and storage (BECCS), green hydrogen, afforestation/reforestation, and sustainable diets. In a survey across six European countries (Germany, France, Italy, Spain, Poland, and the Netherlands; total N = 3,351), we found that providing uncertainty information lowered acceptance, support, and, to a lesser degree, affect, but all measures remained positively evaluated, and differences between measures and countries remained stable. Sustainable diets and BECCS were the least accepted, particularly in Poland and the Netherlands, where participants, on average, were opposed to sustainable diets. Higher perceived uncertainty, especially regarding social and technological feasibility, was negatively associated with acceptance and affect, an effect that strengthened after information, particularly for social uncertainty. Climate change beliefs emerged as the strongest predictor of acceptance among all predictive factors. Trust in scientists also contributed positively to acceptance of mitigation measures, while trust in government and sociodemographic variables showed marginal influence. Our findings underscore the importance of combining social factors with IAMs to better reflect real-world constraints and improve the design and communication of climate mitigation policies.