Climate change science has become a highly politicized and polarized arena, where epistemological debates are intertwined with concerns about economic and political influences on knowledge production. This study examines how climate knowledge is contested and expertise is (de)legitimized within the blogosphere, a space where diverse actors engage in knowledge production outside traditional institutional control. Existing research often focuses on mainstream media's role in shaping public perception of climate change, analyzing how political, corporate, or consumerist discourses challenge scientific evidence. This study, however, explores the multi-voiced nature of online climate change discussions, moving beyond the simplified 'alarmist versus denier' framework to encompass a broader range of perspectives and actors.

Prior research in science communication has investigated how media influences public understanding of climate change and the transition from awareness to action. Studies examining the impact of media coverage have revealed the contestation of scientific evidence by political and corporate interests. Linguistic analyses, including corpus-based approaches, have provided quantitative insights into the language used to represent climate change knowledge. For instance, research has explored how mainstream media frames climate change, revealing a prevalence of gradualist views in some contexts. Other studies have utilized corpora of social media and blogs for automatic text analysis to identify discursive features. This study distinguishes itself by analyzing a corpus of climate change blog posts from a range of perspectives, not limited to the typical 'alarmist vs. denier' binary, offering a more nuanced understanding of the multi-voiced nature of the online debate.

This study employs a corpus-based methodology, analyzing a subset of the Genealogies of Knowledge Internet corpus, specifically the Climate Science Blogger Corpus (CSBC). The CSBC comprises 448,608 tokens from five blogs representing diverse viewpoints on climate change, including both contrarian and acceptor perspectives. The selection of blogs was guided by three criteria: explicit stance on the climate change controversy, varied blogging agendas, and author consent for inclusion in the corpus. The blogs were categorized into two subsets: 'contrarian' (CSBC-CON) and 'acceptor' (CSBC-ACC). The analysis focuses on the bloggers' use of three lexical items – 'bias,' 'dogma,' and 'peer review' – to understand how they construct their authorial voices and engage with competing perspectives. The theoretical framework draws on Martin and White's (2005) concept of 'engagement' within systemic functional linguistics, examining how bloggers position themselves dialogically vis-à-vis alternative viewpoints. Concordance browsers and visualization tools (Metafacet and Mosaic) were employed to gain systematic insights into the lexical networks surrounding these key terms. The analysis distinguishes between 'dialogically contractive' and 'dialogically expansive' engagement strategies to reveal how bloggers challenge or accommodate alternative perspectives.

The analysis reveals distinct patterns in the use of 'bias,' 'dogma,' and 'peer review' across the contrarian and acceptor blog subsets. Contrarian bloggers frequently employ 'bias' to highlight the ideological underpinnings of the mainstream scientific consensus, emphasizing non-epistemic values. They associate 'dogma' with climate science, framing it as a politicized belief system rather than evidence-based knowledge, sometimes using religious metaphors to further discredit the scientific consensus. Contrarian bloggers' views on 'peer review' reflect their overall skepticism, associating it with alarmism and institutional bias, suggesting the system is manipulated to legitimize a partisan agenda. Acceptor bloggers, on the other hand, use 'bias' to highlight methodological flaws and questionable funding sources in contrarian arguments. They rarely use 'dogma,' and when they do, it's often to quote contrarian voices, using a dialogically expansive strategy to expose their bias. Their perspective on 'peer review' emphasizes its role in upholding scientific standards, occasionally acknowledging instances of sloppy practices or corruption to expose weaknesses in contrarian claims. The visualization tools (Metafacet and Mosaic) quantitatively illustrate the uneven distribution of these terms across the two subcorpora, reinforcing the qualitative findings about differing discursive strategies.

The findings demonstrate how contrarian and acceptor bloggers employ different linguistic strategies to construct their authorial subjectivities and engage with the climate change debate. Contrarian bloggers frame the debate primarily as a conflict between competing values and ideologies, while acceptor bloggers emphasize the importance of scientific methodology and evidence. The study highlights how bloggers' use of specific lexical choices reveals underlying assumptions and values that shape their perspectives and engagement strategies. This analysis sheds light on how competing forms of expertise are negotiated in online public spheres and how language plays a crucial role in shaping public understanding of climate change science.

This study contributes to our understanding of the complex interplay between science, politics, and public discourse in the context of climate change. The analysis reveals the strategic use of language to construct competing narratives of expertise and authority within the blogosphere. Future research could explore other evaluative lexis in these blogs and other online genres to further investigate the construction of intersubjectivity and the negotiation of expertise in this increasingly multi-voiced debate. Expanding the corpus to include a wider range of online genres would allow for a more comprehensive understanding of the dynamics of online climate change communication.

The relatively small size of the corpus, while sufficient to reveal significant discursive patterns, limits the generalizability of the findings. The focus on a specific set of lexical items might overlook other important aspects of bloggers' engagement strategies. The study's focus on English-language blogs might not fully capture the nuances of climate change discussions in other linguistic contexts.