This article provides a framework for analysing changes and continuities in science communication. The field is challenged by three contexts: (1) ‘post-normal situations’ of coping with uncertainties, value questions, an urgency to take action, and associated political pressures; (2) a dramatically changing media environment, and (3) a polarizing discourse culture. We refine the concept of post-normal science to make it more applicable to analyse public science communication in an era of digital media networks. Focussing on changes in the interactions between scientists and journalists, we identify two ideal types: normal and post-normal science communication, and conclude that the boundaries of science and journalism are blurring and under renegotiation. Scientists and journalists develop new shared role models, norms, and practices. Both groups are increasingly acting as advocates for common goods that emphasize the emerging norms of post-normal science communication: transparency, interpretation, advocacy and participation.

How users discuss climate change online is one of the crucial questions (science) communication scholars address nowadays. This study contributes by approaching the issue through the theoretical concept of online public arenas. The diversity of topics and perceptions in the climate change discourse is explored by comparing different arenas. German journalistic articles and their reader comments as well as scientific expert blogs are analyzed by quantitative manual and automated content analysis (n=5,301). Findings demonstrate a larger diversity of topics and interpretations in arenas with low barriers to communication. Overall, climate change skepticism is rare, but mostly present in lay publics.