The Climate Change Fork blogs of December 24, 2013 and January 2, 2014 asked why the prospects for world population growth varied so widely – from today’s population of some 7 billion people to the possibility of anywhere between 3.2 and 24.8 billion in 2150. Making predictions more than 50 years out is risky.  In this blog, I will discuss the determinants of that growth and limit the discussion to the year 2050, when world population is predicted to grow to roughly 8 – 10 billion.[i]

Barring massive migration to extra-terrestrial planets, global population growth will continue to be determined by the difference between births and deaths.  If there are more births than deaths, the population will grow. If there are more deaths than births, the population will shrink. It’s as simple as that.

Let’s look at deaths first: Death rates have been declining for more than a century, even taking into account the overall aging of the population and the ongoing HIV epidemic. Purposefully containing population growth by increasing deaths would require us to resort to the apocalyptic factors of war, pestilence and starvation; strategies which few would advocate.

via Jim Foreit Guest Blog: How Does Population Decline? | ClimateChangeFork.