You are right about the challenges we have created for ourselves with carbon pollution. It's hard to say how much worse we will allow this problem to become before we take effective action; already tens of thousands of premature deaths and tens of billions of dollars of economic loss have occurred due to heatwaves, drought and wildfire exceeding the (former) bounds of natural variability.
And we may be (gloomily) assured that this become more pronounced.
Yet the 21st century so far has also seen the biggest political and economic advances by the developing world: prosperity, wellness and freedom have been markedly on the advance during the new millennium around the world. Even Africa, the most tormented continent in the post-Colonial era, has seen generally robust economic growth, an increase in democratic functioning governments, and rapidly dropping child mortality--this despite the HIV/AIDs epidemic, the existence of failed states such as Somalia, and festering political sores such as Sudan. (And despite climatic challenges too--drought has been a real killer in West Africa and the Sub-Saharan area in recent years.)
It reminds me of Charles Dickens' famous beginning words from "A Tale Of Two Cities": "It was the best of times, it was the worst of times..."
Perhaps that's frequently a good description of the human condition.