Understanding the underlying values, beliefs and emotions that influence the public’s perceptions and opinions on climate change (CC)is increasingly important, as CC is a complex and politicized phenomenon. Additionally, optimizing messaging for communicating CC and encouraging greater mitigation behavior can yield significant benefits to global stakeholders. Here we evaluated the effectiveness of informative, persuasive and empathic message frames about a major climate-related local flooding event through online surveys administered to 370 adults in Manitoba and Saskatchewan, Canada and 360 adults in Queensland, Australia. Measures of trust in climate communicators and climate science, concern over CC effects, and belief that most recent floods are due to CC were assessed before and after message exposure, along with related values, beliefs and emotions. Willingness to support pro-environmental groups was assessed as a proxy measure of behavioural intent. Cumulative odds ordinal regression and multinomial regression were used to predict group membership (no support, passive support, active support). Political affiliation, trust and belief in CC, belief in anthropogenic CC, pro-environmental values, and, in some regressions,previous flood exposure, were significant predictors of activism support. Respondents who received the empathic message frame and had low to medium pro-environmental values were more likely to believe the link between flooding and CC compared to those who received the informative message frame. These results, including the finding that some elicited emotions predicted behavioral intent,provide insight into how to construct climate information for groups with varying beliefs, values and experiences, to reduce climate skepticism and encourage pro-environmental behavior.