There is no such thing as "doomed". Humanity is not going to disappear. We can either do better or worse, and there really is no limit to the "worse" side.
Maybe I'm optimistic (for a certain value of optimistic) but I feel we would do mass geoengineering and/or start serious international emission control, enforced by war if necessary, before we get to that.
My very pessimistic view is that things will get very bad first. Which means that humanity will have to deal with mass refugee movements, wars, natural disasters from climate change, and trying to mitigate the effects.
One of those by itself would be difficult to deal with, but all at once would be impossible. In my opinion.
My optimist is that it when it gets real bad governments will do something before it gets catastrophic. Who knows, not a climate scientist, maybe it will be too late.