YouTube is far more than just a video-sharing website. The online platform, which hosts almost two billion users each month, is an archive, a laboratory, a news outlet and an educational tool. It's also a goldmine for climate conspiracy theories.
If you are using YouTube to learn about climate science, an exploratory research project has now shown that most videos in the search engine will expose you to misinformation.
"Searching YouTube for climate-science and climate-engineering-related terms finds fewer than half of the videos represent mainstream scientific views," says study author Joachim Allgaier, a sociologist and communications researcher at RWTH Aachen University.
"It's alarming to find that the majority of videos propagate conspiracy theories about climate science and technology."
The analysis was designed to examine what video content users will see when searching for climate topics, and whether this information adheres to or challenges the scientific consensus outlined by the UN Intergovernmental Panel on Climate Change.
Altogether, ten search terms were employed: climate, climate change, climate engineering, climate manipulation, climate modification, climate science, geoengineering, global warming, chemtrails, and climate hacking.
The last two of these are non-scientific terms often used by conspiracy theorists, and they were included as a sort of 'search control' to find out whether they brought up similar videos.
Using Tor as an online anonymisation tool that removes personal search history, the team combed through 200 videos, roughly twenty per search term.
Remarkably, only 89 of these videos were found to support scientific consensus views about human-caused climate change, and four of those videos include climate scientists discussing topics with deniers.
On the other hand, 107 videos were found to oppose scientific consensus views, with 16 of these videos denying human-caused climate change outright, and 91 spreading conspiracy theories about climate engineering and climate change.
To further estimate the impact of this imbalance, Allgaier also looked at the number of views these videos had received. This is perhaps the most worrying aspect of the research, which found a near-even split between viewers of climate misinformation videos and accurate climate information videos.
While all the videos supporting the scientific mainstream view had received nearly 17 million views in total, those opposing the mainstream scientific position had only 2,294 fewer views.
Obviously, not every term typed into YouTube will bring up the same amount of misinformation. For common scientific terms, like climate, climate change, climate science and global warming, the majority of videos in the sample adhered to the scientific consensus.
The most watched video from science YouTubers, for example, was a video from Veritasium titled "13 Misconceptions about Global Warming", which not only explained the science of climate change but also debunked some of the most common beliefs. It was found by searching for 'global warming'.
While general search terms like 'global warming' are more likely to bring up videos that conform to mainstream scientific positions, more specific scientific terms, such as geoengineering and climate modification, largely do not.
On YouTube, Allgaier argues, these two controversial areas of scientific research have been successfully hijacked by deniers and conspiracy theorists. Combining results for both these terms, it was found that 92.5 percent adhered to the 'chemtrail' conspiracy theory.
"In this sense they are using a relatively recent scientific term [geoengineering] for making their concern sound more scientific and possibly more reasonable to some people," Allgaier explains in the paper.
"From their point of view this strategy also has the advantage that 'chemtrailers' can now jump on the bandwagon when there are actual scientific discussions and events addressing technical options of artificial climate modification or manipulation."
Most of these videos were made by amateurs, who believe in things like the 'chemtrail' conspiracy theory, which posits that evil government forces are spraying the population from airplanes with mind-altering toxins.
Among the sample, there was only one video that challenged the 'chemtrail' conspiracy theory in any way.
"Within the scientific community, 'geoengineering' describes technology with the potential to deal with the serious consequences of climate change, if we don't manage to reduce greenhouse gases successfully. For example, greenhouse gas removal, solar radiation management or massive forestation to absorb carbon dioxide," explains Allgaier.
"However, people searching for 'geoengineering' or 'climate modification' on YouTube won't find any information on these topics in the way they are discussed by scientists and engineers. Instead, searching for these terms results in videos that leave users exposed to entirely non-scientific video content."
Allgaier isn't laying all the blame on YouTube users. He's also pointing the finger at the platform itself. While YouTube holds enormous potential for teaching and communicating science, he says it is too often used to do the opposite.
Unlike news outlets, which have some level of editorial control, social media websites and video platforms like YouTube are fertile ground for misinformation and conspiracies because there is no quality control: anyone can upload whatever they like, regardless of whether or not they have any expertise, or even have accurate information.
Once these opinions are online, they are nearly impossible to obstruct, especially if these distorted views have been mirrored by other channels and spread across social media.
"The way YouTube search algorithms work is not very transparent. We should be aware this powerful artificial intelligence is already making decisions for us, for example, if you choose to use 'auto-play'," argues Allgaier.
"I think YouTube should take responsibility to ensure its users will find high-quality information if they search for scientific and biomedical terms, instead of being exposed to doubtful conspiracy videos."
It's important to note that data collection for this study happened between 2015 and 2018, and YouTube has recently said it would retool it's notorious recommendation algorithm, which has been accused of creating a breeding ground for conspiracy theories and false information.
So these are hardly fresh criticisms, since YouTube has already been accused of spreading falsehoods and arranging search rankings in a way that allow highly active, niche opinions to gain exceptional levels of visibility.
Still, this is one of the first studies to show how detrimental YouTube videos can be for climate science in particular. The results clearly demonstrate that there is a serious reason for concern in the way that YouTube users are engaging with climate topics.
And while Allgaier doesn't pretend to have all the answers, he's calling on scientists and science communicators to join ranks on YouTube or other popular platforms in order to reach the widest possible audience.
"… various individuals and groups that oppose mainstream scientific positions already gained a strong foothold on such channels and seem to have learnt very well how to use them to their advantage," he writes.
Unless scientists and science communicators can do the same, the truth will inevitably become buried in a search engine full of climate conspiracies.
This research was published in Frontiers in Communication.