[Paper Review] Growing polarisation around climate change on social media

Max Falkenberg, Alessandro Galeazzi+9 more|arXiv (Cornell University)|Dec 22, 2021

Climate Change Communication and Perception4 citations

TL;DR

This study analyzes Twitter discourse from 2014 to 2021 around UN Climate Change Conferences (COP), revealing a sharp rise in ideological polarisation during COP26, driven by a fourfold increase in right-wing climate contrarian activity since COP21. The research identifies 'political hypocrisy' as a unifying theme in contrarian rhetoric, highlighting growing online division in climate discourse despite broad international engagement.

ABSTRACT

Climate change and political polarisation are two of the 21st century's critical socio-political issues. Here, we investigate their intersection by studying the discussion around the UN Conference of The Parties on Climate Change (COP) using Twitter data from 2014 to 2021. First, we reveal a large increase in ideological polarisation during COP26, following low polarisation between COP20 and COP25. Second, we show that this increase is driven by growing right-wing activity, a 4-fold increase since COP21 relative to pro-climate groups. Finally, we identify a broad range of ''climate contrarian'' views during COP26, emphasising the theme of ''political hypocrisy'' as a topic of cross-ideological appeal; contrarian views and accusations of hypocrisy have become key themes in the Twitter climate discussion since 2019. With future climate action reliant on negotiations at COP27 and beyond, our results highlight the importance of monitoring polarisation, and its impacts, in the public climate discourse.

Motivation & Objective

• To investigate the evolution of ideological polarisation in online climate discourse on Twitter from 2014 to 2021.
• To examine how the discourse around major COP events, particularly COP21 and COP26, reflects shifts in political polarisation.
• To identify the core themes and rhetorical strategies used by climate contrarian groups, especially those appealing across ideological lines.
• To assess whether the COP26 discussion is representative of broader climate discourse on Twitter.

Proposed method

• The study uses Twitter data collected during and around each COP event from 2014 to 2021, focusing on user interactions and content.
• A latent ideology model is constructed using user-user interaction networks (retweets and mentions) to infer a synthetic spectrum of climate-related opinions.
• Polarisation is quantified using bimodality measures of the inferred ideology distribution across time and user groups.
• The analysis identifies and tracks the use of specific keywords and themes—particularly 'political hypocrisy'—in tweets from minority and majority ideological clusters.
• Statistical models, including linear regression and ordinary least squares, are used to assess trends in activity and cross-ideological engagement.
• Supplementary data from Google Trends, YouTube, and Reddit are used to validate and contextualize Twitter findings.

Experimental results

Research questions

• RQ1 How has ideological polarisation in climate discourse on Twitter evolved from COP20 to COP26?
• RQ2 What role do right-wing actors play in increasing polarisation during major COP events, particularly COP26?
• RQ3 To what extent do 'climate contrarian' views, especially those centered on 'political hypocrisy,' emerge as cross-ideological themes in online climate debates?
• RQ4 Are the patterns observed during COP26 representative of broader climate discourse on Twitter?
• RQ5 How do activity levels and engagement patterns differ between pro-climate and contrarian user groups over time?

Key findings

• Polarisation in climate discourse on Twitter increased significantly during COP26, with a notable rise beginning around 2019, particularly following the global climate strikes.
• Right-wing users showed a fourfold increase in activity relative to pro-climate groups since COP21, driving the surge in polarisation.
• The theme of 'political hypocrisy' emerged as a salient and cross-ideological topic in contrarian discourse, especially during COP26.
• Climate sceptic tweets from the COP26 minority group are highly correlated with broader climate scepticism trends on Twitter, confirming their representativeness.
• There is no significant increase in cross-ideological engagement between majority and minority ideological groups over time, indicating persistent network segregation.
• The COP26 minority group’s activity is strongly correlated with general climate scepticism trends, with a Pearson correlation of R=0.76 in normalized tweet volumes.