The Climate Mitigation Behaviour Scale (CLIMBS) – Development and psychometric evaluation

Background: There is a paucity of valid instruments to assess behaviours directly related with greenhouse gas reduction. In this study, the Climate Mitigation Behaviour Scale (CLIMBS) was developed, adapted from the General Ecological Behaviour framework to capture everyday climate-relevant behaviours across key domains.Methods: An initial 30-item pool including mobility, food, consumption, and engagement themes was refined through expert review and administered to adults participating in an intervention study in Sweden (N = 694). Items used five-point response formats aligned to behavioural frequency. Dimensionality was tested using bifactor item factor analysis (graded response model). Reliability was evaluated via ordinal α and McDonald’s ω. Associations with related constructs, including sustainability interest, knowledge, lifestyle, climate importance, and worry, assessed external validity.Results: A bifactor model with one general factor and four orthogonal domains showed the best fit (RMSEA = .045, CFI = .92, TLI = .91). After removing seven weak items, the final 23-item scale showed a strong general dimension (ω_total = .83, Ω_H = .69). Subscale reliability was acceptable (α = .68–.85). The general factor showed moderate to strong associations with related constructs (r = .39–.55, all p < .001), with negligible age and gender effects. A reduction of the full scale resulted into an 8-item short form (CLIMBS-8), which correlated highly with the general factor (r = .91). Conclusions: CLIMBS is a psychometrically supported measure of climate change mitigation behaviour with a dominant general factor and interpretable domains. The CLIMBS-8 provides a brief alternative with minimal loss of information.