I am not saying humanity will go extinct, I AM saying it is highly likely several billions will die. If global civilization collapses then we could be looking at a reduction of global population by well over half.

I do not see those billions dying peacefully, do you?
You call me a doom and gloom guy... I disagree, I am looking at the data I see and pointing out its implications.

Large sections of the Earth WILL become uninhabitable- where will those people go? How many wars will it lead to? There WILL be global food shortages, how many will die, and how many wars will THAT lead to.

There WILL be a refugee crises several orders of magnitude greater than we have ever seen... and what we have seen has led to a shift towards fascism. When the trickle of refugees becomes a tsunami how do you expect global politics to go?

These are things that are, for the most part, inevitable. I am NOT making up some doom and gloom scenario. I am looking at the situation and noting it is impossible to come up with a realistic scenario where we manage to avoid theses crises.

By 2100, the global population will be a shockingly small fraction of its current level. The majority of that reduction will be the result of very large scale dying- from famine, war, flooding, and heat. It will be a brutally ugly process. And even the well off and wealthy countries will see suffering they have not experienced so far.

Humanity will be greatly diminished and building back up will be much harder the second time around.