Half a trillion is not unrealistic. Take one of the numbers we know with a bit more certainty, Nguesso in the Republic of Congo (not the DRC!) takes only a little over 17% of the oil revenue locally - the rest is "exported" (this low price incidentally is how he has managed to remain in power for so long despite some pretty drastic attempts at changing that).
Africa's GDP is around USD 2.4 trillion so seeing a fifth of that "disappear" seems like a conservative lower bound, actually (admittedly countries like South Africa skew the measure).
Africa's GDP is around USD 2.4 trillion so seeing a fifth of that "disappear" seems like a conservative lower bound, actually (admittedly countries like South Africa skew the measure).