This study aims to explore social bots' role in online climate change discussions. By analyzing 491,279 climate-change-related tweets, we found that social bots were actively engaged in climate change discussions on Twitter and contributed up to 1.5.4% of related contents. Bots promote the saliency of energy, climate actions and climate strikes on public agenda. 83.1% of tweets posted by social bots support climate change activism, and 16.9% support climate change skepticism. However, social bot skeptics are more strategical than social bot activists in terms of launching conversations with opposing-minded humans, and avoiding amplification of opposing voices. They are also more successful in inciting opposing-minded humans' initiative conversation and like-minded humans' amplification. Based on the above findings, we suggest cultivating individuals’ media literacy in terms of distinguishing malicious social bots as a potential solution to deal with social bot skeptics disguised as humans, as well as making use of benign social bots for science popularization.
