Social media have altered communication about climate change over the last 20 years, but have only partially delivered on early expectations that they would broaden and democratize the discourse. A systematic review by the Universities of Zurich and Münster reveals that although a wider range of actors is involved today, established voices continue to dominate it and climate-change skeptics are disproportionately gaining visibility.

When social media arrived on the scene, there were high hopes that they would improve – or even “democratize” – communication regarding climate change by, for instance, lowering access barriers, creating a more direct channel between science and the public, and giving more voices from civil society a chance to exchange ideas and views on the issue, goals and solutions.

Democratization promise only partially fulfilled
That hope has only partially been met, as a stocktaking after two decades of social media by Mike S. Schäfer from the Department of Communication and Media Research at the University of Zurich (UZH) and Julia Metag from the Department of Communication at the University of Münster has revealed. Their review systematically analyzed international research literature on communication about climate change on an array of social media outlets ranging from X, TikTok and YouTube to regionally dominant platforms like Weibo, WeChat, Bilibili and ShareChat.

The study’s findings have now been published in a focus issue of Nature Climate Change dedicated to climate change communication. They show that the promise of democratization has been unevenly fulfilled. According to Schäfer, early studies initially suggested that social media gave more members of civil society and environmental and grassroots movements as well as citizens in general a chance to be heard. “Over time, however, it became evident that established actors – like political actors, government bodies and news organizations – continue to shape and often dominate the discussion and dissemination of climate-related content. Moreover, among the new voices, climate-change skeptics have gained visibility more than others,” Schäfer explains.

Echo chambers between social media platforms
Researchers have long studied echo chambers within individual social media platforms, where people primarily encounter like-minded others. However, recent developments in climate change communication point to an increasing schism between platforms driven, for example, by more stringent moderation and an accompanying migration away from the major platforms, the rebranding of Twitter to X, the changing of fact-checking rules by companies like Meta, and the rise of alternative platforms like Gab, 8kun, BitChute and Truth Social, which deliberately position themselves in opposition to established platforms and moderation norms.

“In the future, divisions presumably will occur less within platforms than between them. Social media users may then be in separate, more homogeneous platform universes where they will come in less contact with differing views,” Metag, the co-author of the article, says. That has consequences for public debate because if that supposition proves true, it would structurally hinder the emergence of a shared societal understanding on climate change, regardless of how well individual messages are framed.

Climate journalism under a double strain
Social media have also put double pressure on climate journalism, on one hand economically because a big chunk of advertising revenue has migrated to platforms like Meta and Google, which erodes the financial base of legacy media houses. And on the other hand, articles and posts with links to external websites are often less prominently displayed than other content. Schäfer stresses that “this undermines journalism in its role as a conveyor of information, including on the subject of climate, particularly affecting media systems with weak public broadcasting services and regions where independent climate journalism is already fragile anyway.”

Anyone interested in the subject of climate change can find more information than ever, including high-quality content, on social media. That’s not the case, though, for people less interested, who make up a large part of society in many countries. Those people are casually confronted with climate-related content less frequently today than they used to be via legacy news media outlets, which set different priorities for the topics they choose to cover. On the whole, climate-related content accounts for only a small fraction of communication on social media, trailing far behind entertainment and lifestyle topics.

No uniform “social media effect”
It is not clear whether social media promote public knowledge about climate issues because study findings thus far do not paint a uniform picture. However, there is evidence of an inconvenient truth: users of social media tend to overestimate how much they know about climate change. At any rate, the researchers were unable to detect a universal “social media effect” across regions and platforms. “The impact of social media depends on the different logics behind the platforms, regulations, media systems and sociopolitical contexts. What’s observable on X in the USA says little about what’s happening on Weibo in China,” Metag explains.