North America - natch. The US may be a declining force but they aren't going away in my lifetime.

East Asia - again natch. China's reassertion of its long-term position disposing of approx 1/3 of world GDP is a cliche because its true.

Europe - will be a multipole of some sort, but the precise nature of the EU's presence will depend upon how the institutions are reformed and what kind of constitutional settlement is finally agreed.

South Asia - it depends on how things pan out in the Islamic world, but I think India will make the step and pull a bunch of others into its regional orbit.

Your other candidates I don't see making it in the near-to-medium future:

SE Asia/Pac Rim - will be the crossroads between NorAm, EAsia and SAsia rather than a multipole of its own.

Dar al-Islam/Central Asia - either the oil hasn't run out, in which case this area remains a satrapy of the other poles (NorAm and China probably) or the oil has gone, in which case the petro-states are turning into C22nd Haitis and everybody else is trying to avoid being sucked down by the undertow.

Mercosur - Uncle Sam's backyard and this won't change by 2050. This is especially true if North America really, truly goes into decline and loses relative position in the Old World.

Africa - the demographic disaster that is HIV (combined with the generally hostile disease environment you get in sub-saharan Africa) will continue to hobble Africa and the 'curse of oil|resources' will get worse as the MidEast drops into the crapper. Africa will be a basket case until the end of the century at least I think.

Russia - should by all rights be a multipole, except all of its blood and treasure is draining into the EU as we speak (write?). The territory currently occupied by Russia will be opened up by Europe and/or EAsia.

Regards
Luke

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