You cant go through life being THAT autistic. You cant take everything THAT literally.
People cant recite the entire Encyclopedea Britannica everytime they open their mouths.
A person who denies the reality of the Nazi Holocaust would be a "Holocaust Denier". In that case the one word "holocaust" suffices.
But if you buy into Trump's public words and believe that the 2020 election was stolen then you, like the above holocaust denier, are denying the reality of something widely accepted as real. The something being that Biden won that election fairly. So you would be what they call an "election denier". Strictly speaking you're not denying all elections. Just that one. But they cant call you a "twenty-twenty Biden election victory denier". So they just call you an "election denier". An everyone knows what the label means (whether they agree with such denial or not).
Likewise the current controversy about climate has to do with the recent (by geological standards) and sudden (by geological standards) rise in global temperature since the start of the industrial revolution two centuries ago.
Scientists say the climate is changing, AND that humans are causing it. Some deny that this particular current trend is happening at all (that climate is even changing now). Some concede that climate is changing but are not convinced that humans are causing it via air pollution.
So the last two are "denying" the consensus of the first group. You could call them "deniers of the current change in climate" or "deniers of human caused climate change". But its easier to just say "climate deniers" or "climate change deniers". And everyone gets what you mean.