Climate anxiety refers to persistent, difficult-to-control apprehensiveness and worry about climate change. Research to better understand the prevalence, indicators, causes, and consequences of climate anxiety is needed, to which emotion researchers can make substantial contributions. First, emotion theory can inform an integrative and functional theory of climate anxiety, mapping interactions between its cognitive, emotional, behavioural, and physiological indicators. Second, appraisal theories can help to understand the reasons why people experience climate anxiety. Third, emotion researchers can contribute to theorizing when climate anxiety motivates climate action, accounting for non-linearity, interactions with other emotions and cognitions, and temporal dynamics. Fourth, emotion researchers can contribute to developing strategies to cope with climate anxiety, for example, by building on emotion regulation theory.