You underestimate humanities ability to adapt. I’d bet in 100 years a lot of food is grown in vertical farms and those can be made (mostly) immune to droughts and storms. It isn’t going to be easy but nor is society just going to throw in the towel when it gets hard.
For sure I’m not a denier just a (semi) optimist. I certainly hope we can figure out a way to get around it but I’d wager we’re looking at the next Bronze Age collapse except the people will be fleeing from the equator this time.
We, as an international society, have been so focused on improvement in material conditions that we haven't really done a proper attempt at looking for a sustainable way forward. Your Bronze Age analogy is spot on; the ancients had global trade and rapidly improving conditions too, and things were looking extremely bright for them. Until it didn't.
As the grandparent stated, "there will be casualties". Sure, I'm quite certain humanity will recover, and probably end up better off than we are now, but that doesn't mean the chain of events leading up to that that won't be hell.
