[quote][b]Posted by:[/b] YakZSmelk [quote][b]Posted by:[/b] Spirit of Ember I'm guessing it's somewhere around 5 billion.[/quote] That cannot be right. If I had to guess without war and with no space travel the Earth would have about 50 billion in the time of Halo. Obviously there was alot of war and alot of space travel. so I would guess the population would be more around the 20-30 billion range in Halo 4. After Halo 4 I'd say around 13-24 billion. That's assuming the blast from the Didact was as insane as it looked.[/quote] But, according to the Bestarium, the population of Earth at the end of Halo 3 is estimated to be only around ~200 million. (Which is described as being a "sudden change".) So, if you take into account how much Earth's population would grow after 4 years plus the population of humans on the remaining UNSC colonies, it would probably add up to around 5-8 billion. But who knows? It's just my guess. [Edited on 12.08.2012 8:07 PM PST]