What percentage of the world's population lives in the northern hemisphere?
Demographers estimate the world population to be 7.41 billion people (estimate as of July 2017.) 88% of the world's population lives in the Northern Hemisphere. Given that the Northern Hemisphere has only 67.3% of Earth's total landmass, this implies that the population density in the Northern Hemisphere is much greater than in the Southern Hemisphere.
Why does the Southern Hemisphere have a lower population density? One third of the Southern Hemisphere's land mass is Antarctica. Even if we factor out Antarctica, the remaining areas of the Southern Hemisphere are still less dense than the population density in the Northern Hemisphere. While birth rates are high in the southern portion of Africa, average life expectancy is much lower than the rest of the world (averaging 50 years versus 70 years worldwide average). Other parts of the Southern Hemisphere have stable but low growth rates. A second reason for a lower population density is that the two countries projected to have the most growth in the near future are in the Northern Hemisphere (India and China), and their average life expectancy averages 70 years, meaning the net growth is greater than in areas with both high birth and mortality rates.