Constructing legitimacy for climate change planning: A study of local government in Denmark

•Analyses the importance of legitimacy in explaining climate change planning institutionalization in local government.•Four propositions derived from a conceptual framework on legitimacy and previous research are validated.•Legitimacy derived from moral and ethical reasoning is found to have low salience compared to cultural-cognitive legitimacy.•Criticizes the way in which agency has been conceptualised and analysed in much previous research on climate change.