Online comment sections can be considered a public battleground for contestation where members of mainstream publics and counterpublics meet. The case of the climate skeptic counterpublic in Germany was chosen to find out where and how members of the counterpublic are speaking out and how the mainstream responds to that. I conducted a hyperlink network analysis to identify potential battlegrounds, followed by a content analysis of 10,262 user comments from different publics (four news sites, six climate blogs). The results show that the skeptic counterpublic, albeit structurally excluded, is successful in brigading mainstream comment sections and countering the mainstream narrative. The conservative comment sections are especially dominated by counterpublic voices. Mainstream users, however, respond critically to them and challenge the skeptics within their own counterpublic.