In the recent book review by The Overpopulation Project, I was alerted to a colossal oversight in my book research.  To be fair (to myself!) the article in question was published while I was completing my book.  Nevertheless, that I missed this article in the rollout of my book is somewhat disheartening.  The work by  Lianos & Pseiridis, concluded that a population of 3.1 billion humans would be sustainable if relying on an average European standard of living.  The Overpopulation Project provides a fantastic review of their article here.

This review makes the distinction between studies which have claimed to have ascertained the ‘maximum’ carrying capacity of the planet, versus the ‘optimal’.  The review characterizes my book - A Planet of 3 Billion - as seeking an ‘optimal’ carrying capacity, while the progenitor of the question which inspired my book - Professor Joel Cohen, in his book How Many People Can The Earth Support explored the maximum.  I did not use that language in my book, but I appreciate the distinction.

The 3.1 billion carrying capacity established in their study is based on a “comfortable European living standard’.  This, indeed, is something I flirt with when considering Mathis Wackernagel’s analysis in his article “If We Were All Swiss”.  Yet, my number comes in a bit lower...closer to 1 billion, if not for my relentless technological optimism.  My title is A Planet of 3 Billion, after all!

Honestly, their reliance on economic statistics rather than geographic analysis leaves me a bit adrift.  However, I look forward to the opportunity to compare notes and analytical approaches to determining our planet’s long term ecological carrying capacity as it relates to human population size.

Stay tuned.  Perhaps the title of my next book release will be A Planet of 3.1 Billion!  Or, we may combine notes, finding that our collective analysis of the human footprint is worse than we, apart from each other, thought.  A Planet of 1 Billion?  I hope not.  While it is feasible for us to approach 3 Billion by 2100, 1 billion feels a bridge to far.  However, I remain open minded.  And, so should you.