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Crowded Planet
A conversation with Alan Weisman
See: http://www.orionmagazine.org/index.php/articles/article/7694

Andrew D. Blechman: Population is perhaps the monumental topic of our time, and yet the title of your book ends in a question mark. Why is that?

Alan Weisman: I’m a journalist, not an activist. I don’t make statements, but I try to find the answers to big, burning questions. This is the big one to me, because it addresses whether we’ll be able to continue as a species, given all the things that we have been doing to our home.

Andrew: The human population stayed relatively stable, or grew at a manageable rate, for tens of thousands of years but exploded in the past century. What happened? How did we humans come to dominate the planet so quickly?

Alan: The explosion began during the Industrial Revolution. Jobs were suddenly in cities rather than on farms. People were living in tight quarters, and that became an incentive for doctors to begin dealing with diseases that were starting to spread much more easily. Beginning with the nineteenth century, medical advances, such as the smallpox vaccination, were either eradicating diseases or controlling the pests that spread diseases. Suddenly, people were living longer, fewer infants were dying.

Andrew: Before that, we were basically at a replacement rate?

Alan: Pretty much. Women would have seven or eight kids, and if they were lucky, two survived. Two is replacement rate. If a male and female have two kids, then they have essentially replaced themselves. Population remained stable because as many people were dying as were being born.

The other thing was that suddenly we learned how to produce far more food than nature could ever do on its own. Nature’s ability to produce plant life has always been limited by the amount of nitrogen that bacteria could pull out of the air and provide as food for plants. In the twentieth century, we discovered how to pull nitrogen out of the air artificially.

Andrew: You’re speaking of the Haber-Bosch process.

Alan: Yes. As a result, we suddenly came up with artificial fertilizer that could produce much more plant life on this planet than had ever existed before. We were at about 2 billion in 1930 when we started using artificial nitrogen extensively. Today we’re at 7 billion. Between 40 and 50 percent of us would not be alive without artificial nitrogen fertilizer. It nearly doubled the food supply.

Andrew: They say that, in some ways, too much abundance isn’t actually good for a population, that it can actually stress it because it leads to overpopulation. For example, if you overfeed city pigeons, they have more babies and the population starts maxing out, whereas if you don’t overfeed them, the population keeps itself in check.

Alan: That’s the paradox of food production-it can ultimately undermine the viability of a population. At a certain point, it expands beyond its resource base, and then it crashes.

To read the full length interview, please click here: http://www.orionmagazine.org/index.php/articles/article/7694


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