Declining sperm counts: Nature's answer to overpopulation?

Epidemiologist Shanna Swan projects that on current trends sperm counts will reach zero by 2045. That shocking conclusion comes from a new book by Swan and her colleague Stacey Colino. Is this nature's way of bringing human population under control? (More on that later.)

In a 2017 study Swan and colleagues looked at "244 estimates of SC [sperm concentration] and TSC [total sperm count] from 185 studies of 42,935 men who provided semen samples in 1973–2011" in North America, Europe, Australia and New Zealand. Men elsewhere may fare better, but the causes of this trend suggest that it is worldwide.

Swan told The Guardian that she blames so-called "'everywhere chemicals', found in plastics, cosmetics and pesticides, that affect endocrines such as phthalates and bisphenol-A." She also pointed to unhealthy lifestyle choices including use of tobacco and marijuana and to rising obesity. Obesity itself has been linked to increasing human endocrine disruption from these same chemicals.

In fact, Swan's warning is not new even though her study makes it more urgent. The issue of endocrine disruption from toxic chemicals burst into public view in 1996 with the publication of Our Stolen Future which detailed the research on endocrine disrupting chemicals for a lay audience.

There have been some minor victories. Bisphenol-A has been largely removed from food containers voluntarily by food processors. But it is still found in many products and the U.S. Food and Drug Administration still claims it is "safe."

I asked at the beginning of this piece whether declining sperm counts is nature's way of limiting human population. The current trend would not just reduce population, but lead to extinction within a century. It is as if the 2006 film Children of Men has been remade with a slightly different plot line.

An analogy for our predicament might be yeast used in wine making. The yeast at first feast on the sugars in the wine, reproducing wildly. In the process, the yeast produce alcohol as a waste product. Eventually, the fermentation process stops as the yeast consume the available sugar and as the alcohol concentration rises and eventually kills the yeast.

We are very much like these yeast as we create toxic chemicals through our industrial processes and then disperse them in ways that allow them to enter the human body. The question we need to ask ourselves is whether we are no smarter than yeast. (This is a perennial question among those who understand population biology.)

Swan's answer might be that so far we are looking more like yeast than humans having free will. Humans are very fond of telling themselves stories about how they differ from other animals and even how humans are not really animals at all. The truth is that given all that humans have done to destroy other species, the animals may rejoice when the last human is gone from the planet.

Whether we give them that satisfaction depends entirely on a mix of politics, money and public pressure. All this is certainly a more complicated process than yeast in a wine bottle. But right now, it looks like the result may be the same.

If Swan is right, the only path to the survival of the human species other than a voluntary end to the production and use of these dangerous industrial chemicals would be the collapse of industrial civilization itself. Wouldn't it be ironic if that's what it takes to save the human race?

Kurt Cobb is a freelance writer and communications consultant who writes frequently about energy and environment. His work has appeared in The Christian Science Monitor, Resilience, Common Dreams, Naked Capitalism, Le Monde Diplomatique, Oilprice.com, OilVoice, TalkMarkets, Investing.com, Business Insider and many other places. He is the author of an oil-themed novel entitled Prelude and has a widely followed blog called Resource Insights. He is currently a fellow of the Arthur Morgan Institute for Community Solutions. He can be contacted at kurtcobb2001@yahoo.com.