The absence of an Arctic ice cap speaks for itself. Nobody can fake that! Same thing for the countless bare mountain tops, and the rivers that are running dry because there's not enough snow melt from these mountains to feed their tributaries.
This insane desire to "be right" on the part of those who deny the obvious is going to have consequences. I suppose that's OK for old people who will be gone by the time it gets really bad. But what about future generations? Is feeding a rapacious ego really more important than leaving behind a world that future generations can live in?