Exploring climate change discourses on the internet: a topic modeling study across ten years

This study examines online discourses about climate change using automated text analysis. Samples of web contributions from various sources, such as blogs, online newspaper articles, readers' comments, tweets, and others, were collected in 2013, 2019, and 2023. The major themes people talk about when discussing climate change on the internet were identified using structural topic modeling. The study also explored how people discuss climate change differently when using different types of media channels and how the main themes change over time. Six major topics were identified for each point in time; associations between topics and media types were examined. Three topics emerged repeatedly: Dispute over the reality and the implications of climate change, discussions about aspects of the science of climate change, and discussions about causes and consequences of global warming such as sea level rise. In 2019 and 2023, the topic of action (what to do) and the topic of looming disaster showed up repeatedly. Topics limited to one specific corpus were policy discussions, debates about emissions, about renewable energies, about agricultural implications, and expressions of despair. The topical structure could be organized in two general groups, one group containing more science-related topics, and another group containing expressions of dispute, disagreement, and affect. A significant correspondence between media type and prevalent topic could be detected. Media such as Twitter/X and comments are dominated by dispute and despair expressions, whereas media such as blogs and journalistic online articles are primarily concerned with scientific topics in general, as well as with specific topics concerning global warming or renewable energies. In sum, we found noteworthy topical invariances across ten years, and systematic correspondences between topics and media types. The study contributes to the understanding of online discourses about climate change and highlights the role of media type in shaping these discourses.