  Public discourse on critical issues such as climate change is progressively
shifting to social media platforms that prioritize short-form video content.
Content creators acting on those platforms play a pivotal role in shaping the
discourse, yet the dynamics of communication and audience reactions across
platforms remain underexplored. To improve our understanding of this
transition, we studied the video content produced by 21 prominent YouTube
creators who have expanded their influence to TikTok as information
disseminators. Using dictionary-based tools and BERT-based embeddings, we
analyzed the transcripts of nearly 7k climate-related videos across both
platforms and the 574k comments they received. We found that, when publishing
on TikTok, creators use a more emotionally resonant, self-referential, and
action-oriented language compared to YouTube. We also observed a strong
semantic alignment between videos and comments, with creators who excel at
diversifying their TikTok content from YouTube typically receiving responses
that more closely align with their produced content. This suggests that
tailored communication strategies hold greater promise in directing public
discussion toward desired topics, which bears implications for the design of
effective climate communication campaigns.
