Background: The climate crisis has a wide range of direct and indirect mental health impacts on populations. However, their quantification is limited by the lack of unified definitions and assessment tools. The aim of this systematic review is to map all psychometric instruments used to measure emotions associated with the climate crisis, evaluate their psychometric characteristics, and identify any existing gaps. Methods: The protocol was registered on PROSPERO. Data were reported following the COSMIN Risk of Bias of PROM and PRISMA checklists. Original articles describing the psychometric properties and/or validation of self-report measures designed to assess eco-anxiety and other climate change-related emotions in the general population were within the scope of this review. PubMed, PsycINFO, and Web of Science were the search engines used. Findings: A total of 10 different psychometric scales measuring various eco-emotions were identified. Four focused on anxiety, while the remaining six focused on combinations of other negative emotions. The definitions of eco-emotions were not consistent across papers. Most of the instruments were developed in the Global North. Six of the instruments were multidimensional. All but one scale included at least one item indicating behavioural, cognitive, or physical aspects of emotions toward climate crises. The most recurrent emotion was worry, followed by anxiety, fear, and sadness. Including ten scale development studies, a total of 22 studies reporting instrument validation were reviewed. Two of the instruments have been validated in other populations. Interpretation: To what extent the emotions covered by the instruments may overlap in relation to climate change is, to date, not clear. This is due to the lack of consistent definitions of climate-related emotions. Moreover, the mention of emotions was derived by a top-down approach, in all included studies. No positive emotions, such as hopefulness, humor, anticipated pride, gratitude, optimism, or feeling strong to do something though own contributions, have been detected.

All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf and declare: FKA received funding from the Scientific and Technological Research Council of Turkey (TUBİTAK) to conduct postdoc research in the University of Groningen.

FKA was funded by the Scientific and Technological Research Council of Turkey (TUBİTAK) to carry out postdoc research at the time this study was conducted (Grant Number: 1059B192202875). The funding source had no specific role in study design, in the writing of the report; or in the decision to submit the paper for publication.

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