... The world's population has passed through three distinct growth periods . development of tools - rise to ~1 million, 10,000 yrs ago . ... technology - rise to over 1 billion The current world population is estimated as ~5.2 billion (1990) and is expected to double by ~2010. ... the Black Death killed between 30% and 40% of the European population between 1346 and 1355, after creating similar turmoil in the mid-East, India and China (see Philip Ziegler "The Black Death") . ...