It means that if you are in a "first world" economy, your living standards will drastically decline, while if you are in a "third world" or perpetually undeveloped or "developing" country, your living standards will rise modestly only, if at all.
1.5 billion * 10 sol + 5.5 billion * 2 sol = 26 billion sol
26 billion sol / 7 billion = 3.7 sol
So first world reduced from 10 down to 3.7
Third world raised from 2 up to 3.7
(sol = relative standard of living estimate)
Note 1: This is just a "back of the envelope" estimate, but if you paid attention to algebra back in middle school, you should understand what I wrote.
Note 2: As population increases and resources are depleted, all sol will decline.
Note 3: Your rulers, even in the "third world" or perpetually undeveloped or "developing" countries, will still have their palaces, mansions, air-conditioned limos, etc., while encouraging you to sacrifice and "live green".