Is there anything global warming deniers will admit we know?

Actually, that's one half of the rhetoric of a global warming denier. They will often make the claim "we really don't know anything and to say otherwise is arrogant" and then follow it up with "human activities aren't causing global warming...it's a hoax" - a contradiction. Global warming deniers are a strange breed. The purpose of their existence is to protect large entrenched industries and confuse the public.