Population Bomb or Population Crash: A Tale of Two Worlds

The booming Boca Grande district of Cartagena, Colombia. Matt Miller/TNC

The booming Boca Grande district of Cartagena, Colombia. Matt Miller/TNC

by Rob McDonald, Senior Scientist for Sustainable Land-Use

One of my biggest frustrations with the press in this online era is the pressure to pick one simple story to describe an incredibly complex issue.

An ongoing story line for journalists and bloggers is how rapid population growth is posing numerous problems for society and the environment. This story line has been around a while: it traces its modern form to Paul Ehrlich’s famous book The Population Bomb, and it has been critiqued for just as long.

In the last several years, there has been a wave of stories written from the opposite perspective. The rate of population growth is actually falling, and Europe and Japan are actually losing population, so the real problem is the population crash.

This is a catchy story, because it fits into the “everything you thought you knew about X was wrong!” category.

Jeff Wise, in a piece in Slate, carried this story line to its absurd conclusion, suggesting (I hope somewhat in jest) that if this trend of falling birth rate continued, “in the long term—on the order of centuries—we could be looking at the literal extinction of humanity.”

Both stories have an element of truth.

More to the point, each story is true for one of two very different worlds.

In developing countries, there is still relatively rapid population growth, although it is slowing over time as millions move into cities and become (on average) better educated, healthier, and wealthier, all of which correlate with having fewer kids.

While the rate of population growth has slowed, it not stopped: rapid population growth, particularly in cities, will be one of the major issues these countries have to deal with when planning infrastructure or striving to protect their environment.

There will be more than 2 billion new people in cities by 2050, a rate of urban growth that is absolutely astounding. In 3 days, the world builds enough new urban homes to house all of Washington, DC.

From the perspective of the environment, the rapid growth in population plus the rapid rise in incomes (and hence consumption of natural resources) will pose real threats to the environment.

So the next several decades in these countries will be defined by dealing with population growth. After that crunch, things may slow down considerably, although I don’t particularly worry about lower fertility rates leading to the “literal extinction” of a country like China.

In developed countries, there is a trend for the average woman to have less than 2 children, which over time does shrink populations in these countries. This does pose significant problems for social welfare systems where the current generation of workers pays for the care of their parents, but this is not an intractable problem.

For one thing, economic growth continues in developed countries, and this economic growth is often faster than the rate of population decline. Germany’s GDP grew at a 3% rate in 2011, while its average annual change in population is around -0.2%, so every year there are slightly fewer workers that are significantly wealthier.

The main problem for governments is that health care payments tend to grow faster than GDP growth rates. Governments have to save more now so they will have enough money in future decades to pay social welfare payments, given the demographics. But that is a solvable problem.

Putting those issues aside, it could actually be a tremendously good thing for society and the environment if population levels slowly declined in developed countries. There is no reason the economies of Germany or Japan or the United States couldn’t provide an even higher quality of life to their citizens in 2030 or 2050, even if their population was smaller.

From an urban planning point of view, the emptying out of cities provides a unique opportunity to redesign urban form. And for the countryside, a smaller population actually provides some interesting opportunities for environmental restoration.

Think about how the forests of New England (and the moose and other wildlife) returned after agriculture was abandoned. A similar re-wilding will happen in a number of other places around the world–providing additional opportunities for conservation.

Opinions expressed on Cool Green Science and in any corresponding comments are the personal opinions of the original authors and do not necessarily reflect the views of The Nature Conservancy.

Posted In: Science

Dr. Robert McDonald is Senior Scientist for Sustainable Land-Use for The Nature Conservancy. Dr. McDonald researches the impact and dependences of cities on the natural world, and is the lead scientist for the Conservancy’s urban conservation program, under the leadership of its director Laura Huffman. Dr. McDonald has recently led a NCEAS Working Group into how global urban growth and climate change will affect urban water availability and air quality. He also researches the effect of U.S. energy policy on natural habitat and water use. Prior to joining the Conservancy, he was a Smith Conservation Biology Fellow at Harvard University, studying the impact global urban growth will have on biodiversity and conservation. Dr. McDonald has also taught landscape ecology at Harvard’s Graduate School of Design, helping architects and planners incorporate ecological principles into their projects. He earned his Ph.D. in Ecology from Duke University.



Comments: Population Bomb or Population Crash: A Tale of Two Worlds

  •  Comment from Escape Hunter

    Major changes are taking place, indeed…
    Some regions are rapidly depopulating (some of the most shocking trends in Eastern Europe – worse than Western Europe and Japan), other parts of the World are registering more and more inhabitants (Bangladesh is about the size of Bulgaria, but its population is about half the size of the USA’s population!).

    New metropolises will emerge in 10 years time. Places like Lagos, Mumbai, Chennai, Chongqing, Dhaka… But from the ecological point of view, they are time bombs. Chinese cities are some of the worst examples.

    Sadly, legendary cities are decaying: Detroit, Brussels, Paris are turning into slums.
    What’s interesting is that many of the 3rd World’s cities are evolving technically and economically surprisingly well, while some Western cities are losing industrial potential and are turning into slums.

    The West will have to struggle prevent other cities going the “Detroit way”. Which is also an ecological disaster scenario – besides the socio-economic effects.

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