Concerned or Apathetic? Exploring online public opinions on climate change from 2008 to 2019: A Comparative study between China and other G20 countries.

G20 countries, account for the majority of global carbon emissions, need to take the lead in mitigating climate change. However, there are differences in economic, political and sociocultural backgrounds amongst G20 countries, especially between China and other G20 countries. Since the implementation of climate policies largely require domestic public support, it is vital to explore similarities and differences of public opinions on climate issues between China and other G20 countries. However, little research has investigated the micro-level climate concerns from the perspective of cross-country differences. Therefore, based on big data and text mining analysis, this study crawled user-generated data on Sina Weibo (N = 271,487) and Twitter (N = 4,874,546) from 2008 to 2019 to comprehensively catalog and compare climate opinions. Results show that climate change has become a salient issue in China and other G20 countries, with climate-related surges in public opinions always occurring after major natural, social and political events. Moreover, in China, there has been a significant shift in public attention from climate impacts to climate mitigation strategies, but in other G20 countries, people are more radical by emphasizing the climate movement and calling for authoritative actions. This study provides "snapshots" of climate communication and offers a quantification-based reference for promoting climate actions and collaborative governance.