Abstract This study examines how public issues emerge and diffuse in a global public sphere, taking the example of climate justice. Using large-scale data covering news, social media, and academic publications between 2017–2022 and inspired by complexity science, we analyze trends in issue salience, the role of focusing events, and the dynamics across media environments and countries. A quantitative, cross-national, comparative approach was employed, drawing on global datasets from GDELT, X, and Scopus (N = 10,978,484), with salience measured by mentions of the issue in each environment. Findings show an increase of issue salience across all environments. On social and news media, climate justice discourse follows distinct cycles with salience peaks driven by activist-led focusing events and their social media campaigning. Climate justice diffusion has been shaped by uneven geographies: while news salience is highest in climate-vulnerable countries of the Global South, major attention spikes often originate in the Global North. Lay summary This study explores how the idea of climate justice—the belief that those people hit hardest by climate change are often the least to blame for it—has gained growing attention around the world. By analyzing more than 10 million news articles, social media posts, and academic papers from 2017 to 2022, the research tracks how this issue has moved across borders and platforms. Findings show that big moments—like protests, climate marches, and major UN conferences—spark sudden attention waves. Social media often leads the conversation, with news coverage picking up the momentum. Although the impacts of climate change fall heaviest on the Global South, and climate justice is most discussed in those countries, many of the largest attention spikes are linked to activist events in the Global North. The study finds that climate justice is not just a part of the broader climate change discussion, but has its own unique dynamics. It also reveals how climate justice is unevenly spotlighted across countries. Through collective action and social media, people raise their voices to bring attention to justice in times of climate crisis.
Heß et al. (Wed,) studied this question.