Saturday, January 15, 2011

Interesting And Disturbing Population Trends

This version of this post originally appeared on Red Green and Blue on 1/25/10.  I have re-posted it in response to a recent GRIST posting saying we need to talk about "population control."  The comment stream includes many examples of people who have a very negative attitude about our own species, but what few people seem to realize is that birth rates in the developed world have already dropped - in many cases to alarmingly low levels.  In those parts of the world the problem is not over-population but rather the implications of a rapidly aging population.  (Click here for a list of other posts on various sites)

Trends in the proportion of children
Fertility rates are declining around the world and most of what is written about this trend casts it in a positive light.  The cover story of last November's Economist magazine carried the headline: "Falling Fertility - How the Population Problem is Solving Itself."  It claimed that countries like China are enjoying a "demographic dividend" over the coming decades.  As positive as an end to human population increase might be for the planet, the question that is not getting much attention is, "what next?"  After population reaches an inflection point and begins to decline, what will society be like?  I won't live to see this, but my grand daughter who was born last month certainly will.
My good friend John sent me a link to the IIASA website (International Institute for Applied System Analysis) where it is possible to download data from their models of global demographic trends (I've made some graphs of that data).  Most such models stop at 2050 but this one goes out to 2100.  If these models are correct, there are some major challenges ahead for humanity.  The most immediate is how to feed the population that will continue to increase until about 2060.  The next is how to deal with a population that is getting very old.  If you are an American, the trends in the following graphs should be seriously unsettling.  We have a dysfunctional, hyper-partisan-dominated, political establishment that is chronically unable to find reasonable solutions to the challenges of medical costs, Social Security insolvency or immigration reform, and yet addressing these very issues will become even more critical in the future pictured in these graphs.

Fewer and Fewer Children

The first thing that strikes me (see graph above) is the declining proportion of children.  This global trend is well under way in the developed world and is only slightly less so in North America because of immigration.  I wonder at what point colleges will start competing for the few remaining students?

Proportion of societies that will be over 80

More and More Old People

The opposite trend is occurring in terms of the octogenarian segment of the population. Look at the graph above and imagine what Medicare is going to cost in 20-30 years!  Maybe we can start converting elementary schools into assisted living facilities.

Proportion of the population in the traditional working age category

A Declining Workforce

The biggest concern that I see is the impending decline in the proportion of the "working age" population in every part of the world except Sub-Saharan Africa.  Who is going to do the jobs that require physical stamina?  Who is going to do construction or take care of labor-intensive crops?  Why should people continue to come to work hard in a place like the US that unethically continues to rely on a force of immigrant laborers to whom they won't even give "guest worker status?"  In not that many years, the nations of the world will be competing for a shrinking supply of able-bodied folks willing to do physically challenging jobs.  In the decades after that I'm relatively sure that labor-intensive crops (like many fruits and vegetables) will become very high priced delicacies.  Only the crops that can be highly mechanized will be affordable in a world that will still have a major food supply challenge until the last part of the century. 

Trends in the working age population

Aging Baby Boomers

Of course, In the short term, the big shift will be the huge increase of people in the 60-80 year-old range as we "baby boomers" age.  It has been obvious for decades that our generation would break the existing Social Security system that is based on a massive wealth transfer from the younger generation to the older.  Of course that obviously inevitable problem has never lead to any reform or adjustment of the system because it has always been too easy to turn logical ideas into negative campaigning ammunition.  It is clear that we are going to need to keep as many of the baby boomers as possible in the work force (and tax base) until 70 or 75.

Trends in the dependency ratio

A Growing Burden for the Young

IISAA tracks an interesting statistic called the "Old Age Dependency Ratio" which is simply the projected population over 60 divided by the projected population of "working age" people between 20 and 60.  Look how many regions will have six people over 60 for every ten working people by 2050!  Even if we manage to keep people working past 60, the most age-challenged countries will increasingly want to be able to attract people of reproductive age through immigration and tax policy.

Population growth and the resulting increase in food demand is certainly an issue for now, but simultaneously we need to find ways to deal with these demographic trends and their impact on societies.

I would be interested to know your reaction to this information. You are welcome to comment on this post or to email me at

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