Commentary: Population and Sustainable Development

Aug 14, 2017

The United Nations estimates that world population will increase to 11 billion by the end of the century. UD professor Bob Brecha is thinking how population and sustainability are related and bring us this commentary.

When I was born, world population was less than half what it is today.  I think it’s clear that one reason we’ve started talking about sustainability at all is that the large human population is placing a lot of stress on ecosystems and natural resources.

But even today, it’s really only around one billion people who are heavily consuming resources. Most of the world’s population actually leaves a fairly small footprint on the earth.  In the end, it’s not necessarily the number of people that matters, but the total impact, as measured by population multiplied by how much each person consumes.

The challenge we face is that most of us believe that it would be a good thing if we could somehow lift the world’s poor out of poverty, but increasing affluence correlates strongly with more consumption of resources.  And that will mean more stress on natural systems.  So two of the greatest challenges we face are to reduce poverty while minimizing impacts – not an easy task.

Back to the issue of population.  If decreasing poverty might already add to environmental pressures, projected increases in population will certainly just make it worse, right?   Let’s step back just a bit.  In 2015 UN member countries agreed to work toward 17 Sustainable Development Goals including reduction of poverty, improving health outcomes, decreasing child mortality, and improving educational access, particularly for women.

It’s long been known that empowerment of women, especially in terms of education access, is a strong predictor of decreases in birth rates in developing countries. However, the UN population estimates are made by assuming a kind of business-as-usual future, in which current birth rate trends continue.   If the world actually acts on the Sustainable Development Goals by 2030, helping alleviate poverty and other ills for more than half the world’s population, then the indirect effect will be to decrease the rate of population growth.

This is all kind of complicated, but the real message is simple.  There are far too many people in the world who live in poverty and far too many women who lack empowerment.  Working with countries to alleviate poverty and enable human development in terms of education, health and other measures is not only long overdue, but would help lead to world population peaking at 9 billion in a few decades instead of growing to 11 billion by the end of the century.  We could still argue about whether that’s too many people for our earth system to handle without damage, but all else being equal, fewer people and fewer desperately poor people in the world is better than the alternative, for many reasons.

Bob Brecha is a professor of Physics and Renewable and Clean Energy at the University of Dayton, and Research Director at UD's Hanley Sustainability Institute.  Follow him on Twitter: @BobBrecha