Not just denying the existence of climate change (which I doubt very many people dispute) but the causes of it, which is significantly more controversial, "scientific consensus" or not.
> prohibit ads for, and monetization of, content that contradicts well-established scientific consensus around the existence and causes of climate change
https://support.google.com/google-ads/answer/11221321?hl=en
> prohibit ads for, and monetization of, content that contradicts well-established scientific consensus around the existence and causes of climate change