Russia is panicking for a stable currency right now. Africa is being non stopped raped with Ebola and presidential assassination, China just lost a shitton of workers, India and Brazil suck.
Dunno who your doomsayer is, but he's misinformed.
While I am not much of a doomsayer I have to disagree. China and India are the 2nd and 3rd largest economies in the world (adjusted for PPP).
While I do not think that alone will make them powerhouses of the world, it is definitely something to worry about. Our biggest allies are corruption, lackluster education, and inefficiency which is what keeps many Asian countries in the crapper (ESPECIALLY China and India).
As far as Africa, they will be important in 80 years or so (MUCH longer if we pump/mine them dry before they civilize themselves). I'm pretty sure genocide and war are bigger problems then Ebola or an occasional political assassination.
Fortunately China's military technology, organization, and training are embarrassingly terrible. India's is even worse. China has plenty of economic might but lacks the political influence and connections to be a world problem. If they choose to assemble and use that military might to physically "claim" the South China Sea they would have carved out a decent size empire. There is oil and possibly other valuable scarce resources under that water and China having a monopoly on it wouldn;t be good for the west.
We can crush them anywhere on the earth more than 50 miles from the physical borders of China. If we get closer than that we would have a more soldiers than the US + UK could deal with realistically.
We (MURICA!) have technological superiority, world influence, air superiority, way better allies (EU,UK), superior information services (spies), economic might, and hotter bitches than all those countries combined.