Seriously, it's going to suck and cause many, many issues. But the planet won't be completely uninhabitable for many centuries, if it ever even happens, through man made climate change.
Do you remember the Syrian refugee crisis and how it destabilized pretty much all of Europe and how we're still dealing (or failing to deal) with the political consequences of these upheavals?
How do 1.5 billion migrations by 2050 sound to you? Yeah. Many many issues.
And I'm not even going into the discussion that the whole planet will be toast once we reach +5 degrees celsius, which looks more and more not only like a extreme outlier but a real possibility instead.
Fun times ahead.