There has certainly been lots of doom and gloom in the past, with some (not all) of it quite justified - look how close we came to nuclear annihilation multiple times during the cold war. It was only cool headed individuals that kept all of humanity from a tragic end. Those fears were well justified, and we're getting to a similar situation right now, so close that William J. Perry thinks we're at the highest likelihood of nuclear war since the Cuban missile crisis.
Those war-based risks are of a very different (political) nature however, one that doesn't persist after the war pressures subside. With climate change, we're in a much different situation, and one that I'm actually not sure we're up to solving. If we look at progress so far, I don't think it looks good.
It's a shame it's being converted into a political and tribal game. We're talking about the survival of an advanced species here (hell, it might be the only one). There is literally nothing more important than that.