As a side note - we have, in fact, pretty much solved the problem of population growth as a species. The main growth engine is the increase in life span by now. Birth rates have been steadily falling (UN long term models actually assume that they will be growing again in the future for the developed world), the only problem being that the slowdown has been somewhat slower in some parts of Africa than expected, but it is still falling quickly. The population will grow for the next 50-100 years, but we will probably have to deal with a declining population after that.

(already wrote in another thread, but) They just didnt take it (the money going into the GDP of another countries) into account! Let me cite them:

"Although GDP is a measure of government and consumer spending plus business investment plus exports minus imports, for the purposes of this project IDC did not account for exports or imports."

Then again, what would you expect from BSA?