Three studies investigated habitual worry about global warming as an example of 'eco-anxiety'. The key question was whether such worrying is constructive (a motivated pro-environmental response) or unconstructive (a symptom of pathological worry). Pathological worry and worry about global warming were assessed together with two other worry sources, that is, personal issues and the world economy (Study 1) and personal issues and the corona virus (Study 2). In both studies a statistically significant correlation was found between pathological worry and global warming worry. However, this relationship was nonsignificant when controlled for the other two worry sources. Comparisons between Studies 1 and 2 conducted one month before and during the COVID-19 crisis, respectively, as well as between order conditions within Study 2 suggested that global warming worry was unaffected by the COVID-19 context. Study 3 demonstrated that global warming worry was associated with the perception of a proximal and distal threat, and correlated positively with determinants of pro-environmental behaviour, that is, a pro-ecological worldview, pro-environmental values, past pro-environmental behaviour and a 'green' identity. Global warming worry also correlated positively with emotion clusters signifying determination, anxiety, and anger, respectively. The three studies together suggest that while habitual global warming worry may be unconstructive and part of intrapersonal dysfunction for some individuals, for many others it is a constructive adaptive pro-environmental response.