What is Earth's Optimum Human Population Level?

Posted on January 6, 2006

Chris Rapley has an article about whether the Earth has an optimum human population level and what this number might be. Clearly the Earth cannot handle the 6.5+ billion people on Earth today -- at least not the way these people are currently using up resources and emitting pollutants.
So if we believe that the size of the human "footprint" is a serious problem (and there is much evidence for this) then a rational view would be that along with a raft of measures to reduce the footprint per person, the issue of population management must be addressed.

Let us assume (reasonably) that an optimum human population level exists, which would provide the physical and intellectual capacity to ensure a rich and fulfilling life for all, but would represent a call upon the services of the planet which would be benign and hence sustainable over the long term.

A scientific analysis can tell us what that optimum number is (perhaps 2-3 billion?).

With that number and a timescale as targets, a path to reach "Utopia" from where we are now is, in principle, a straightforward matter of identifying options, choosing the approach and then planning and navigating the route from source to destination.
Nearly all of the growth comes from the less developed countries according to a press release from UN's population division from February.
World population is expected to increase by 2.6 billion over the next 45 years, from 6.5 billion today to 9.1 billion in 2050. Almost all growth will take place in the less developed regions, where today's 5.3 billion population is expected to swell to 7.8 billion in 2050. By contrast, the population of the more developed regions will remain mostly unchanged, at 1.2 billion.
Find a way to stabilize populations in third-world countries and maybe the population growth will slow to a crawl or even fall. However, this may not help the pollution problem if a significant amount of it is coming from the more developed nations -- or if the more developed nations create the worst types of pollution.