Published on The Water Blog

Of pigs, pythons and population growth – setting the record straight

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The Nairobi Central Business District.
Photo: Sarah Farhat/The World Bank

I am constantly startled by references to “population growth” as a cause of a number of development challenges.  Whether it’s urbanization, food security, or water scarcity, all too often “population growth” is cited as a cause for pessimism or even a reason not to strive for progress.  I can almost see Thomas Malthus grinning at me from the shadows.

It gets worse. I recently reviewed a paper where higher fertility among minorities was touted as an explanation for their poverty! A few months ago, a respected professional wrote asking why we weren’t doing more on family planning, since fertility in Africa would pretty much stymie any efforts to provide infrastructure-based services! I hear statements to this effect routinely from policy makers in charge of infrastructure ministries and projects (“how can we keep up with the population?” or “nothing we do will be enough unless we control the population”) but am always amazed when I hear them from scientists of different hues.

So I thought I’d try to set the record straight:

  1. Basics first: Fertility is declining across the board. But despite a projected secular decline, the momentum will stay robust until the cohort that is now about 10-14 years old, “exits” (or dies off to put it bluntly!).  So, we won’t see the effects of fertility decline on absolute numbers until the “pig leaves the python”, as we demographers say. If you want to understand what’s really happening with population growth and its ultimate stabilization, watch the iconic Hans Rosling in this delightful film
  2. Restating the obvious: Africa is very heterogeneous. Fertility in Africa is projected to decline to 3.9 children per woman by 2030  (from about 4.7 during 2010-2015) and down to 3.1 children per woman by 2050. The highest fertility is in sub-Saharan Africa, with Southern Africa having fairly low levels by comparison.  So yes, Africa does indeed have the fastest growing population. but not “uncontrolled” fertility (except in very few countries).  Family planning, child survival, and female education will have huge impacts on the highest fertility countries, but the trajectory of most other countries is a declining one already. 
  3. Here’s the real challenge: the intersection between fragility and fertility runs deep and stays strong.  Of the top ten highest fertility countries, nine are in Africa, and eight of those are listed as being fragile. There are several reasons for this:  women everywhere want to have control over their fertility , but in fragile situations, they don’t have access to birth control, and there’s a high “unmet demand” for contraception. It may well be the case that these are also high infant mortality regimes, and fertility may be a strategy for risk mitigation.  

    So, fertility is highly correlated with crisis, uncertainty, and poor access to services. 
  4. Yes, of course numbers matter: Food and water scarcity, pressures on urban transport or on roads are correlated with how many people there are. But as a brilliant primer from the Population Reference Bureau alludes – it’s not about “over-population” but about bad management of scarce resources.  As I have said before, in the case of water and food, it is largely an issue of allocation – both the efficiency and equity sides of allocation. 
  5. So, what’s really messing with infrastructure?  It often depends on whom you ask – the causes range from financing to availability of land and resettling people in densely populated areas.  But why do infrastructure based services affect some people more than others?   The short answer is: poor management and the politics behind it! Policy and its implementation are often not accountable to those who are affected by scarcity the most.
Thankfully, others are also tackling the myths head-on – I’d like to recommend Nick Eberstadt’s five myths about global population.  Let me know what you think.


Maitreyi Bordia Das

Director, Trust Funds and Partner Relations, Development Finance (DFi)

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