History repeats itself.

there are many examples of civilisations that exceeded their access to a support base in Nature and catastrophe occurred. Much of their populations drifted away elsewhere.

Our globalised society today is much larger and pushes the limits much harder, so the fall will be more painful. There is almost nowhere left for out population to drift to, especially the size it is. It is starting to occur in Africa for some time, and you are currently watching it occur in Kashmir.