Google to Block Ads Next to Content Denying Climate Change

Alphabet Inc.’s GOOG 1.33% Google will no longer allow digital ads bought on its platform to appear next to online content that denies climate change, a ban that will also apply to YouTube, the company’s giant online-video service.

The ban applies to “content that contradicts the well-established scientific consensus around the existence and causes of climate change,” Google, the world’s largest digital-ad company by revenue, said in a blog post Thursday. It also applies to any content denying that human activity or greenhouse gas emissions contribute to climate change.

Google’s move aims to cut off a major source of income for providers of climate-change misinformation. Google’s $147 billion in ad revenue comes from selling ad space in its own products, such as YouTube, as well as from brokering ad sales on thousands of sites across the web.

A spokesman for Google said the company would use a “combination of automated tools and human review” to enforce its policy.

Google is the leading provider of tools used in the many steps of purchasing and selling online ads—whether they are meant to run on Google’s own platforms or sites around the web. Google is expected to take 29% of global digital-ad spending in 2021, according to research firm eMarketer.

For several years, Google has prohibited advertising on certain content that is deemed misleading to the public or unattractive to advertisers, including civic disinformation, disinformation about the coronavirus pandemic and some content featuring minors.

Critics have said Google’s enforcement has been lax and ineffective at restraining the spread of disinformation.

NewsGuard, a company that tracks and rates news sites it says traffic in objectionable information, published a report earlier this year that said more than 4,000 brands have bought ads on websites publishing Covid-19 misinformation since the pandemic began. “In most cases, the advertisements were likely inadvertent, placed by algorithms on programmatic ad-buying platforms like Google’s DV360 rather than intentionally by the brands involved,” said NewsGuard, which was created by Court TV founder Steven Brill and former Wall Street Journal publisher L. Gordon Crovitz.

The Google spokesman said the company frequently takes action when content is found to be violating its policies, noting that Google removed ads for policy violations from “thousands of sites” in the last month alone.

Other tech companies including Facebook Inc. have instituted policies to limit the spread and monetization of disinformation on their platforms. Former Facebook employee Frances Haugen said the company’s efforts have been ineffective, and she testified before a Senate subcommittee about that and other issues this week.

Last week, YouTube said it would remove false claims that vaccines cause autism, cancer or infertility, among other things, expanding the video platform’s efforts to curb Covid-19 misinformation to other vaccines.

The Google spokesman said the company’s policy banning ads on content denying climate change takes effect in 30 days. In addition, advertisers will be prohibited from purchasing ads that deny climate change or that link to a webpage that denies climate change, he said. That policy affecting advertisers takes effect in 60 days, he said.

Write to Patience Haggin at

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Appeared in the October 8, 2021, print edition as ‘Google Bars Ads on Some Climate Sites.’