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Greenpeace is not happy that its advertisements were found on YouTube videos featuring climate change denialism and misinformation.

The environmental nonprofit on Thursday called on YouTube to change how it handles content that denies or downplays global warming, pushing the social media giant to pull ads and change its recommendation algorithm.

The ads were brought to Greenpeace's attention by Avaaz, a nonprofit global advocacy group, which issued a report Thursday saying environmental organizations and major brands were unaware that their commercials were running alongside climate misinformation.

Travis Nichols, a spokesperson for Greenpeace USA, said in a statement that YouTube's actions follow those of other companies who have profited by casting doubt on the science of climate change.

"If we're going to stop the climate crisis, we need tech and social media companies like YouTube to be part of the solution, not part of the problem," Nichols said.

Avaaz's report found that YouTube's algorithms have been "actively promoting" videos containing inaccurate information about climate change and pairing them with ads from 108 brands, including the technology giant Samsung, the cosmetics and personal care product maker L'Oréal and the ride-hailing service Uber.

L'Oréal said it was working with YouTube to remove its ads from videos that included climate denialism or misinformation.

"The information promoted by these videos is in direct contradiction with L'Oréal's commitments and the work we have been carrying out for many years to protect the environment," a spokesperson for L'Oréal said in a statement.

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The report found that some of the groups, which also included the environmental organization World Wildlife Fund, were unaware that their ads were appearing alongside climate misinformation.

YouTube said it works with advertisers to ensure that their content appears in places that fit with their brands. For example, the platform allows advertisers to exclude their ads from videos related to climate change or global warming.

"YouTube has strict ad policies that govern where ads are allowed to appear and we give advertisers tools to opt out of content that doesn't align with their brand," a spokesperson said in a statement. "We've also significantly invested in reducing recommendations of borderline content and harmful misinformation, and raising up authoritative voices on YouTube."

YouTube's recommendation algorithm has come under scrutiny in recent years for its propensity to favor videos featuring misinformation, conspiracy theories and extremism.

YouTube said it has made strides in promoting authoritative channels. Last February, YouTube's parent company, Google, released a white paper detailing how the organization aims to fight disinformation across its products and advertising systems. On YouTube, the proposed efforts included prioritizing authoritative voices, reducing "borderline" content and removing videos that violated the company's guidelines.

Nell Greenberg, Avaaz's campaign director based in Oakland, California, said the study was meant to show that YouTube's recommendations favored climate denialism. She acknowledged that there were limits to the study, because YouTube does not make data about its algorithms public.

Avaaz used a developer tool known as YouTube Data Tools to find related videos for three search terms: "global warming," "climate change" and "climate manipulation." Because related videos make up only a part of the recommended content in YouTube's "up-next" feature, the study does not perfectly mimic the experience that regular users may have if they manually search for those terms and consume content on the platform.

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The study analyzed 5,537 related videos from Sept. 18 to Sept. 24 that were associated with the three search terms and found that videos containing climate misinformation were among those recommended to users in the up-next feature.

For the search term "global warming," for example, 16 percent of the top 100 related videos contained inaccurate information about climate change. Eight percent of the top 100 related videos contained climate misinformation for users who searched for "climate change," and for the search term "climate manipulation," the proportion was 21 percent.

Although those related videos make up only some of the videos served to users in the up-next feature, Avaaz found that the videos it included in its study had collectively garnered 21.1 million views.

"We're not talking about removing content from the site — that's a free speech issue," Greenberg said. "What we're talking about is the free advertising that YouTube provides to this content with its algorithm."

Greenberg said Avaaz has had discussions with YouTube about the study's findings.

"I can tell you that the people we talk to at YouTube take this stuff very seriously, but they need more emphasis from their executive leaders ensuring that not promoting misinformation and disinformation is a priority," she said. "And they need a more systemic approach."