Environmental groups slammed Elon Musk’s X app, formerly known as Twitter, in a report Wednesday ranking social media platforms on their approach to climate change misinformation. 

X ranked last in the scorecard because it’s not clear the app has policies against the spread of misleading information about climate change, according to Climate Action Against Disinformation, the creator of the scorecard. The group is a coalition of more than 50 environmental groups, ad agencies and other organizations. 

Finding false climate information is relatively easy on X, with some of the platform’s large accounts posting that climate change is a “hoax” or conspiracy theories about green energy projects. Musk himself has said erroneously that what happens above ground has no impact on climate change. 

The stakes are high, according to the coalition, because false information about climate change has stalled action including further limits on fossil fuels. 

“A toxic and fossil-fueled minority is drowning out the voices of science and reason and social media platforms are complicit,” Erika Seiber, a spokesperson at coalition member Friends of the Earth, said in a statement. 

The coalition formed in 2021 as environmental groups worried about misinformation around that year’s U.N. climate summit in Scotland. Its members include Friends of the Earth, WWF International and Patagonia, each with its own source of funding.

The Climate Action Against Disinformation coalition timed the report for release during Climate Week NYC, when figures from civil society and other sectors meet to discuss strategy on climate change, and during this week’s session of the U.N. General Assembly.

Before Musk bought Twitter last year, the app said it banned advertisements that “contradict the scientific consensus on climate change.” Now, though, it’s not clear that the ban has continued into Musk’s ownership. 

“In the case of X/Twitter, Elon Musk’s acquisition of the company has created uncertainty about which policies are still standing and which are not,” the report says. 

Representatives for X did not respond to a request for comment from NBC News. The researchers said they also reached out to X in preparing their scorecard but did not hear a response. 

X notched a score of 1 on the scorecard’s 21-point scale. The app’s only point came from having a privacy policy that’s easily accessible and readable — something that researchers said was important in fighting climate misinformation because fossil fuel companies, like other advertisers, can use personal data to sway public opinion. The worst possible score was zero. 

Pinterest did the best on the scorecard with 12 points. It was the only platform that had set out to define climate misinformation in detail in its community guidelines and the only one that releases an annual report on climate misinformation trends, researchers said. (Other platforms define misinformation in general, not specific to climate.) 

Pinterest also got credit for banning the monetization of climate misinformation and for trying to protect the personal data of people who protest fossil fuels. 

The company said Tuesday that it was proud of its work. 

“At Pinterest we have a long history of creating policies that help to build a positive place online. Fighting misinformation is complex and always evolving, so we’re constantly evaluating our guidelines and enforcement approaches,” Pinterest said in a statement. 

Pinterest was followed by TikTok at 9 points, Meta at 8 points and YouTube at 6 points. The scorecard didn’t measure all apps that sometimes fall under the umbrella of social media, but the researchers said they’ve held meetings with other tech platforms not covered in the report including LinkedIn and Wikipedia. 

Social media researchers have for years expressed alarm at the spread of climate change denial, arguing that tech platforms are adding to problems such as rising sea levels if they don’t take a more active role in taking down misleading content. Climate-related conspiracy theories are sometimes intertwined with other misinformation, including about Covid-19, and the theories sometimes spike after extreme weather events, including among Spanish-language users. 

The platforms have begun to take a harder line against climate misinformation, employing different strategies. 

In 2021, Meta, then known as Facebook, said it would label posts that include climate misinformation and direct users via a link to a new information hub to promote scientific findings. Outside researchers said, though, that Facebook didn’t always apply the labels. 

That same year, YouTube said it would stop climate deniers from being able to make money off its system — although as of this year, some deniers were still doing so, The New York Times reported in May. 

In a statement responding to the climate scorecard, YouTube said: “Our climate change policy explicitly prohibits the monetization of content that denies the existence of climate change, as well as ads that promote these claims. Debate or discussions of climate change topics, including around public policy or research, is allowed, but when content crosses the line to climate change denial, we stop showing ads on those videos. In general, our systems also don’t recommend or prominently surface content that includes climate change misinformation.” 

YouTube also said it raises videos from authoritative sources in search results and recommendations. 

TikTok had no immediate comment on the scorecard. Meta did not immediately respond to a request for comment. 

The scorecard from the Climate Action Against Disinformation didn’t systematically evaluate how well the social media apps are enforcing their policies but whether the policies exist at all and how comprehensive they are. 

Weighing down all the scores: None of the platforms give researchers or academics reasonable access to non-personal data about content and advertising, the scorecard said.