The main geopolitical change is that oil is not going to be anymore a king-maker. I would expect a second Arab Spring (though the Arab world is more than just the Arabian peninsula) with more success. I would expect a lower influence of Russia as well.
Yes, the decline in power of the petrostates would need to be handled well, and would definitely be important in figuring out how the overall landscape looks.
There are two possible flavors of future and really, both are credible, it depends on the stories you want to tell: more integration in supra-national entities or more independent states.
I think perhaps both could work at the same time (which I upon rereading see that you mentioned further down!)? More autonomy to regional entities within countries, but more collaboration on larger issues inside unions such as EU and AU (it would be difficult to avoid centralized power being forced down on local communities though). Maybe instead of seeing the EU moving towards a federal state, maybe we see the US moving towards something like the EU? There are several nations in Europe that would only be mid-sized states in the US, so I always found comparing single European countries to the US makes less sense than comparing the US and EU directly.
Also, do not forget the UN. It could consolidate in a form of government. It already has a de facto minister of trade (WTO), of labor (ILO), of health (WHO), of education (UNESCO). It is a slow process but solving the climate crisis could have given it the political credit it is currently lacking.
Interesting, I never thought of these bodies in that light before. I think the source of the lack of political credit is largely due to the ineffectiveness of the Security Council and the veto vote. I think a big change to this would be paramount for UN to work as some kind of “world government”. And there is a fine line between such an organization being a force for good or a force for evil.
Cheers! For now, what listed above is what I am most interested in reading up on :)
Sure, go ahead!