Public engagement in the climate change issue will likely be critically important to meaningfully address climate change. However, climate communication has historically had limited success in engaging the public and inspiring action on a large scale, making some question the effectiveness of dominant communication strategies centered around evoking fear. Humor has emerged as a new climate communication tool, but little is known about its persuasive and mobilizing potential – especially in relation to threatening messages. In this study, I conduct an experiment on Swedish students aged 18–30 using two informational videos about climate change: one humorous threat appeal and one non-humorous, ‘pure’, threat appeal. I measure the effects of one-sided satire in threatening climate communication on four key variables: climate-related self-efficacy, message agreement, climate change risk perception, and political engagement intentions. Results show that humor significantly increased self-efficacy, while not producing statistically significant effects on message agreement, risk perception, or political engagement intentions on an aggregated level. Moderation analyses suggest that age, previous climate change interest and gender significantly impacted humor effects, with interest moderating two out of four relationships and age and gender each moderating one. Exploratory subgroup analyses further revealed extensive and somewhat unexpected gender differences in the response to humor. These findings shed light on the need for nuanced discussions on the effectiveness of climate change humor, as well as the importance of targeted campaigns to maximize persuasion.