Ad exchanges can’t seem to keep themselves from sending money to climate deniers — even when it’s flagrantly against exchanges’ own policies.

Check My Ads research, published in a new report from the Climate Action Against Disinformation (CAAD) coalition, shows how over 150 ad exchanges are enabling the monetization of climate mis- and disinformation on 15 key websites, including Breitbart, Newsmax, and Townhall.

Ad exchanges (aka adtech companies) are marketplaces where online ads are bought and sold. Publishers offer “inventory” — like banner ads on sites or mobile apps — and advertisers bid for those spots. The exchanges are generally vague about how their services work in practice, often keeping advertisers in the dark about where, exactly, their ads are appearing and where their money is going.

And the report, tied to the UN’s climate change conference, COP28, highlights that the top exchanges sending money to disinfo sites are owned by companies you see every day: think Google, Amazon, and Microsoft.

Critical contributors

Twenty-five adtech companies stood out as critical connectors to ad revenue, including exchanges owned by Microsoft, Google, Amazon, and Yahoo. Each helped to place ads on at least 8 of the 15 websites analyzed — sites including Breitbart, Newsmax, The Washington Times and Townhall, which all host ad-monetized content that rejects the premise of human-caused climate change. (For the full table of sites analyzed, and why they were picked, download the full CAAD report here. CAAD is a global coalition of over 50 leading climate and anti-disinformation organizations fighting the threat of climate mis- and disinformation.)

Out of 157 ad exchanges, the worst offenders were AppNexus (owned by Microsoft), Pubmatic, and Rubicon Project (owned by Magnite). These exchanges monetized 13 out of the 15 websites analyzed, bringing climate disinformation into the advertising ecosystem.

Many of the ad exchanges on that list — including Google, Amazon, Criteo, and OpenX — have explicit policies meant to prohibit publishers from using their ad products if they publish content contradicting the scientific consensus on climate change, or if they repeatedly push false or misleading claims about climate change.

But that didn’t stop Google from placing Toyota ads on a piece of climate denialism from Breitbart.

And Criteo placed an L.L. Bean ad on a piece from Sky News Australia saying that climate change is good, actually. Meanwhile, Criteo’s own Supply Partner Guidelines prohibit display ads containing content that “shares mistruths and falsehoods” or “is intentionally designed to shock or horrify the user or generate attention through intentionally misleading or grotesque claims.”

We assume that Toyota and L. L. Bean wouldn’t exactly be thrilled that their brand is being used to monetize and give legitimacy to climate lies. Just a guess.

Reverb from the echo chamber

Climate disinformation delays climate policy actions that are needed today. By helping to monetize and this content ad exchanges play a major hand in helping disinformation flourish. They also help legitimize the disinfo claims by placing reputable brands next to content – normalizing these claims.

From our list of examples in the report, the most widely shared story from the Daily Telegraph, the debunked “Climate scientist admits overhyping impact of global warming on wildfires to get published,” was shared in 8,888 X/Twitter posts, replies and retweets.

These sites don’t exist in a vacuum. The false claims were amplified by the likes of Jordan B. Peterson (over 4.8m followers), DiscloseTV (over 1.2m followers), and UK journalist Andrew Neill (1.2m followers).

Letting them know

If ad exchanges cared about the havoc that climate change is wreaking, like making hurricanes and wildfires more catastrophic, then they wouldn’t be sending ad revenue to this dangerous content.

But they are, even when they have policies against it. Exchanges must be held accountable to brands who depend on these policies to ensure safe, conscious placement.

If you work with one of the ad exchanges in our list, tell them funding climate disinfo isn’t acceptable: They must drop sites that use your money to spread climate lies and cut off their ad revenue.

Free speech does not mean free monetization.