The big problems are going to be when unstable weather patterns destroy food harvests and we end up with huge famines and wars over food crops and liveable habi

The big problems are going to be when unstable weather patterns destroy food harvests and we end up with huge famines and wars over food crops and liveable habitats. Currently the world's food production is very much just-in-time, so there's going to be hungry people. Civilisation is only ever three meals away from collapse.