Academics and Research / News

Three Questions: Paul Sutton on the world population reaching 7 billion

Paul Sutton, a DU associate professor of geography and director of the geography department’s graduate studies program, has been with the University of Denver since 1999. He teaches population geography, ecological economics and geographical statistics.

The world’s population is expected to reach 7 billion. Why should this be of interest to those of us in Colorado?
Serious problems with serious consequences should be of great interest to everyone. Sadly, we choose to ignore many serious problems because they are difficult to solve and because there is little immediate penalty for doing nothing right now. The ever-growing human population is one of these problems, as is the global debt crisis, peak oil and climate change. I often tell my students that my father was born in 1926, and the world’s population was presumed to be just under 2 billion then. In my father’s lifetime (and he is still alive), he has seen Earth reach a human population of 2 billion (1927), 3 billion (1960), 4 billion (1974), 5 billion (1987), 6 billion (1999) and 7 billion (2011). That is incredible global change in the span of a single human lifetime. We ignore this important reality at our peril, for it has profound impacts on our economy, society, environment and political stability.

In the 1960s and 1970s, concerns about population growth were front and center on the environmental agenda. Today, you barely hear about it. Why?
We barely hear about the population issue for many reasons, including:
1)     It is hard to deal with, and there is no immediate penalty for doing nothing about it.
2)     It remains contested, as many academics have pointed the finger at resource consumption in wealthy nations being more of an issue than increasing numbers of people in the developing world.
3)     Tackling the population problem is a political lose-lose issue.
4)     The problem seems to be solving itself as fertility rates are declining worldwide. (This New York Times article has a cacophony of perspectives, some of which argue that declining population growth rates are even an undesirable thing.)

But given the depletion of our natural resources, it’s hard to argue that declining fertility rates are a negative. Just think about oil. Our supplies are shrinking as the population continues to grow. Comedian Jon Stewart prepared an incredibly funny montage of videos of the last eight U.S. presidents exhorting the American people about the need for the U.S. to wean itself from foreign oil and move beyond a petroleum-based economy. Our energy challenges seem to get a little more lip service than concerns about population growth, but even so, we don’t hear about energy issues much until gasoline reaches $4 a gallon. We will run out of fossil fuels. We may have reached peak oil already. If we haven’t, we will definitely reach it in the lifetime of the students of DU’s class of 2012.  So, we will reach peak oil as the world’s population grows by 2, 3 or 5 billion more people. We ignore peak oil as we ignore concerns about the growing human population, and these two problems interact in some very challenging ways.

What does continued population growth mean for the world’s economic prospects and for the environment?
It is surprising how little economists think about population growth and resource constraints when explaining the economy. The classic circular-flow model of the economy we find in most Econ 101 courses involves households and firms exchanging capital, labor, money, goods and services in a very tidy closed loop. This is a very inadequate representation of the economy. It is analogous to a biologist representing the metabolism of a mammal using only its circulatory system. The mammal, like the economy, also has a digestive system that imports matter and energy and exports waste and entropy. We have ignored the “digestive system” of our economy for too long, and as our population has grown, we are running out of energy to feed into our economy and producing more waste than our environment can absorb. (Increasing CO2 concentrations in our atmosphere and the great Pacific plastic garbage gyre provide two examples.) It does not strike me as rocket science to suggest that a growing human population will present increasingly difficult challenges to humanity with respect to maintaining environmental quality and sustaining economic growth.




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