Collapse Through Infertility

At this rate, infertility may wipe us out before climate change can.

Photo by Nastassia Ustyan on Unsplash

According to a recent study, the mean sperm count of the global male population declined by 51.6% between 1973 and 2018.

According to the data, global sperm count has been declining at a rate of about 1.16% per year since 1972 but has accelerated to an average decline of 2.64% per year since 2000. When you add these numbers up, they show that the average sperm count globally has decreased by over 50% over the past 50 years.

Low sperm count does tend to mean there is a lower chance of sperm fertilizing an egg. In the end, it is just a numbers game. The less sperm, the lower the odds of conception. Low sperm count does not mean a couple can’t get pregnant, it may just take more time to get pregnant for the average couple. However, if you extrapolate that delay in conception to a global population and expect sperm counts to continue to decline at an accelerating rate, then the odds of conception continue to flag, meaning far fewer children in future generations. 

Don’t worry it happens to every guy.

This is potentially an enormous global health problem. Male fertility is of course directly tied to birthrates. If this trend continues and sperm counts continue their precipitous fall, at some point the population of many countries will fall off a cliff, exacerbating the already serious problem of aging populations in most of the world.

If Earth suffers a population collapse instead of a more orderly glide path down to a few billion fewer people - which is projected by the end of the century – that would be a huge problem for humanity. Having fewer people means we have fewer people to work, to care for an aging population, and to have more children. Smaller and smaller generations with a consistently decreasing sperm count may not be a death spiral for humanity, but it is a “far fewer people on the planet” spiral, that will reinforce itself until something causes people to want bigger families, or the environment that is causing lower sperm counts changes.

The impacts on the global economy of an ever-decreasing population will be profound. Ever since the Industrial Revolution, humanity could usually be counted on to produce an ever-increasing cadre of workers and consumers. That math has changed, and we will have to discover a new economics and a new economic system to adjust to a decreasing global population. 

Some might think an ever-decreasing population is a good thing. After all, every person on Earth has a carbon footprint, so the less people we have, the less emissions we have, right? That may be true, although a managed transition to a lower population is preferable to collapse. Population collapses are likely to bring more chaos and unrest. A more gradual decline – such as what is happening in most developed countries, will still present challenges, but not as extreme as a collapse.

The modern world is not sperm friendly.

So, what is causing this pronounced drop in male sperm count and therefore male fertility? Researchers and still working on that, but it seems clear that there are multiple environmental factors at work. A recent review of studies on chemicals, pesticides, and sperm count shows that the plummet in sperm count can be linked to pesticides.

The period of decreasing sperm counts also coincides with the increased use of plastics around the world. The chemical PBA in many plastics has been shown to lower sperm count.

Other environmental factors, like increased obesity, a more sedentary lifestyle, and increased stress may all play a role as well.  Scientists will continue to study this, but the circumstantial evidence certainly seems to point to environmental factors.

Could it be the climate that is causing this? Maybe, maybe not. It would be even more scary if it wasn’t because studies show that increased temperatures can negatively impact sperm count. So as the world gets hotter, levels of infertility may get even worse.

A study from 2021 titled: Male fertility thermal limits predict vulnerability to climate warming, shows that sperm count is adversely impacted by consistently increased temperatures. The study was concentrated on fruit flies, not mammals, but the results are not encouraging, in that they saw a distinctive drop in fertility as temperatures rose, controlling for all other environmental factors.  

The film Children of Men may become a documentary.

Last week I wrote about the carbon footprint of each human being on Earth and noted that the solution is changing the way we live, so as not to overstress Earth’s systems.

I mentioned that the United Nations predicted the population of Earth would be about 10.9 billion by the end of the century. I then noted that the report by The Lancet predicted that the global population would peak at about 9.7 billion by 2064 and decline to about 8.8 billion by the end of the century. I then argued that that number would be lower, both because the Lancet likely underestimated deaths from climate change, but also because people would choose to have fewer children due to the constantly deteriorating state of the world due to climate change and other environmental stressors.

I left out one important thing. Even if people want to have children, they will be increasingly unable to do so.

The sperm counts of men around the world will likely continue their precipitous fall, as none of the suspected environmental or lifestyle changes are likely to change anytime soon without quick and impactful policy action. If sperm counts continue to decline by over 1% per year, natural disasters increase in frequency and impact, increases in famine lower the global population and despair from climate change causes people who can have children to not have them, we could see a precipitous drop in the global population.

I haven’t even factored in future bad decisions by our leaders that could lead to mass famine in the future, or other events that result in a massive loss of life. Both India and China have over 1.4 billion citizens. Famine brought on by extreme heat or extreme weather, wars, or poor political choices could result in tens of millions or hundreds of millions of deaths. The cultural revolution in China was believed to have cost about 2 million lives. That was fifty years ago when China’s population was much smaller. China imports most of the food and energy needed to run the country and feed those 1.4 billion people. If war, a global famine, or poor internal governance threatened those systems, the results could be catastrophic. Add in climate change and other environmental challenges and the potential for death on the scale we have never seen becomes more possible. Few countries are fully independent, and most import food and fuel to some degree. China is just the biggest example.

In a world of strained resources and increased food shortages due to climate change, we are likely to see famines (yes plural) become global in the coming years and grow in their impacts as the years pass by and the world bakes.

I wouldn’t be surprised if the number we hit by 2010 is somewhere around 5 billion or less. I won’t be around. But tell my kids that I was right if I was. That is – if they are still around.

There is a silver lining. The patriarchy.

In most societies in the world, for better or for worse, men run things. According to a recent World Economic Forum report, LinkedIn data indicates that the share of women in senior leadership positions is at 32.2% in 2023 nearly 10 percentage points lower than women’s overall 2023 workforce representation of 41.9%. The proportion of women globally who are heads of state is about 11 percent.

As we continue to get more definitive answers as to what environmental causes are behind plummeting sperm counts, you can expect more action in the form of environmental legislation to address those problems.

So, if you want to solve climate change or other environmental problems, convince the leaders where you live (they’ll probably be men) that their sperm depends on it.

They might listen to you then.