Even that isn’t a guarantee.

no, it isn't a guarantee, but it's likely. moth won't tell you that addressing climate change isn't terribly important, or that millions or perhaps billions of people aren't going to die in the coming decades, but one small ray of hope is that it would be incredibly difficult for us to kill all of us. whether by climate change, or nuclear war, most scientists agree that it is unlikely to mean the extinction of humanity, let alone all life. and as long as some single cell organisms remain, the planet will eventually recover, and life will flourish again.

now, if we don't address climate change, then millions or perhaps billions of us will die in the coming decades. the grim reality of that, is that killing off that many humans would do wonders to address climate change. many people will starve, but the survivors will inherit a world in which nature retakes what it lost in a world suddenly empty of humanity. even a couple decades in such a world would drastically improve conditions for life.

will that mean humanity isn't doomed? well, no. everything has an end, even humanity. at some point, we will die off, even if we take perfect care of the planet. but that doesn't mean that life will end, and I'm sure whatever comes after us will be just as special and amazing and awe-inspiring as we were.