  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.
