This blog is intended to go along with Population: An Introduction to Concepts and Issues, by John R. Weeks, published by Cengage Learning. The latest edition is the 13th (it will be out in January 2020), but this blog is meant to complement any edition of the book by showing the way in which demographic issues are regularly in the news.

You can download an iPhone app for the 13th edition from the App Store (search for Weeks Population).

If you are a user of my textbook and would like to suggest a blog post idea, please email me at:

Saturday, April 18, 2015

A Path to a Sustainable Future? Part 3-Population

Population growth is inevitable for the next few decades, but we will have a more sustainable future with fewer, rather than more people. Population growth over the past half century is intimately bound up with the ecological disaster that we face in a world of business as usual. Bringing population to a halt sooner rather than later is important for all of us and there

is some good news on this front from researchers at the Wittgenstein Centre for Demography and Human Capital in Vienna, which is a collaboration of IIASA and the Vienna Institute for Demography. They have published a new book with accompanying online resources to help us understand their new population projections that take not only age and sex into account (per the United Nations projections), but also education (a major component of human capital). When they take into account the rising level of education among young women around the globe, their medium projection suggests that population size could peak at about 9.4 billion in the 2060-2080 period. This is a sooner peak and a smaller number of people than implied by the United Nations’ projections, which do not take educational attainment into account. Fertility is closely associated with female education, so as education increases, we can reasonably project that fertility will also go down.

Note, by the way, that these are the same sets of projections from which estimates of the population by religious affiliation were prepared by Pew Research in collaboration with IIASA and VID, as I discussed earlier. Remember that religion per se is not a hindrance to a decline in fertility. There are numerous Muslim majority countries, for example, with below replacement fertility, most notably Iran. And, of course, Catholic Christians have dramatically lowered their fertility over the past few decades, with Catholic majority countries of Southern Europe having among the lowest levels of fertility in the world. As I have said repeatedly, it is not religion, but rather the fundamentalists within a religion group that tend to promote high fertility, almost always in the context of second-class status for women. Education for women is the key remedy. 

At the same time, the Wittgenstein Centre researchers argue that an increasingly better educated older population (which the world has been experiencing over the past century) means that an increasing fraction of the population that is older is not predictive of a decline in productivity and thus of economic malaise. Indeed, the opposite very well may prevail, suggesting that aging and eventually declining populations are not the end of the world. Indeed--they are signs of sustainability.


  1. Recent stuff on Japan:

  2. Prof Weeks - THANKS for this series on the Path Towards A Sustainable Future. I think it is excellent and thought-provoking.

    I have been taking a very careful look at the population trends on Max Roser's web site, along with his ideas about "demographic transitions". Therefore, a key question appears to be this. CAN THE WORLD simply head towards the year 2050, adding about 2 billion more people, and we simply NUDGE ourselves into a pathway for sustainable life on Earth?

    Let me say that PERHAPS this is possible for some countries. For example, I mentioned Germany - which is making a major effort to achieve sustainable energy (non-fossil, non-nuclear). Maybe they can get there.

    BUT can everyone get there? Here is the key problem - as I see it. When we add another 2 billion people to this planet, where are they going to go? I will argue that most of this population growth will be in underdeveloped countries (Africa, Asia). And that most of these new additions to the global family will be poor people - on the bottom of the economic pyramid. Therefore, these people are going to wind up living in slums and ghettos. Hence the REAL question we are asking ... can the world really exist in the 21'st century if we ADD another 2 billion ghetto residents. Can it?

    I have not seen any demographic data for the world's ghettos. I would argue that if we are serious about understanding the future of the world - then the demographics of ghettos is probably a VITAL piece of information. All that I can tell you, from my own personal experience (having been inside the ghettos of East Africa), is that I have the greatest difficulty imagining how we can expand the ghetto population by another 2 billion people ... without it bouncing back on us in a MAJOR way. Those ghettos are already "time bombs waiting to explode" today. Truly!!

    Can the first world (USA, Europe, Japan) switch to a Sustainable Economy, while the world's ghettos enlarge by another 2-billion people ... during this century. THIS QUESTION - is the key driver for what will happen to Planet Earth in his century.

    Pete Pollock, Redondo Beach, CA

    1. I share your concerns, but in response to students who want to think positively, I really do recommend the Lester Brown book. He's not necessarily known for bringing a smile to faces, but I found his book inspiring in the sense that change can come very quickly to places like Africa and Asia. These regions bypassed landlines for cell phones and now have a high penetration of cell phones with which they can do a lot to help themselves. They can also quickly transition to solar powered home accessories without a huge investment in power grids. In some ways, it will be easier for the poorer countries to move ahead in this transition than it will be for the rich countries, where we can expect resistance from people who want to cling to old technologies out of their own self-interest.

  3. Prof Weeks - I agree that you want to keep students moving in the direction of POSITIVE.

    Here is a practical dilemma. Suppose I did decide to compile the "demographics of ghetto". This task is nearly impossible. A ghetto is a very unfriendly place to collect data. Sometimes I think it is a minor miracle that I have gone into them - and come out of them - one one piece. BUT let's imagine that I collected demographic data for 200 households inside a ghetto. That's possibly only 800-1000 people. Roughly. It doesn't seem plausible to "extrapolate" that data set and claim that the same age distribution applies to the entire ghetto of one million people. There's a serious issue there about 'validity'. The problem is, to collect a larger data set is almost impossible. The ghetto is a "living animal" ... how do you track mortalities, how do you track births, how many people immigrate into a ghetto each year, how many emigrate and never come back, how many young men are shot dead by the cops and just disappear? It is a frontier of humanity that exists in some kind of "fog" as far as information is concerned. How do we model - a place where data is almost impossible to assemble? It's a real enigma. I am thinking about it.

    I suggest that you have your students study Germany and Japan. Germany is doing great things with sustainable energy. Japan also has some far-reaching concepts for energy production and transport. Smaller countries with advanced technologies (and excellent education) are likely to be the places where much innovation takes place.