As I was reading Henry Gee’s “Humans Are Doomed to Go Extinct,” I was reminded of an iconic scene from one of the many “Star Trek” movies. In “Star Trek II: The Wrath of Khan,” the ship’s captain, James Kirk, rushes to the engine room to discover that his friend Spock is staggering around in a compartment now filled with lethal radiation. Kirk’s instinct is to rush in and try to save Spock. But, Kirk is held back by his colleagues in order to prevent the deadly radiation from flooding the entire engineering area.

“He’ll die,” Kirk says. “He’s dead already,” one of his colleagues responds, meaning that Spock has already received a fatal dose of radiation. Kirk is too late to save Spock. But it turns out that many fictional characters survive because of Spock’s sacrifice.

It does not seem to Henry Gee, however, that any similar heroic sacrifices by one individual or a few will save humankind. The human race is collectively like Spock; it may be walking around, but it is dead already as a species—and the final demise is coming soon by evolutionary standards.

Gee, a paleontologist, evolutionary biologist and editor at Nature, writes: “There comes a time in the progress of any species, even ones that seem to be thriving, when extinction will be inevitable, no matter what they might do to avert it.”

The reasons humans are in trouble are clear:

  1. Very little genetic variation. Humans are remarkably uniform genetically, a trait which makes any species vulnerable to extinction when circumstances change. Gee remarks: “There is more genetic variation in a few troupes of wild chimpanzees than in the entire human population.”
  2. Declining sperm quality. This may be due to pollution or to stress related to high-density living or both. But it spells rapidly declining fertility. When the number of births goes below the number of deaths, we will be on a terminal slide.
  3. Habitat destruction. The perpetual economic growth paradigm which humans have adopted is leading them to appropriate and destroy huge swathes of the planet. Not only are we destroying and degrading habitat for millions of other species, we humans also suffer from the destruction and degradation since it is our habitat, too.

When you’ve reached the peak of an endeavor, all that is left is the decline. Gee clearly believes humans have reached the apex of their advance—humans are, after all, spread throughout the planet. He expects extinction to arrive “soon.” If it is the paleontologist in him speaking, this could mean in, say, the next 50,000 years. But that is not the tenor of the piece. It is clear the Gee is talking about a collapse much sooner when he ends with this: “[I]f we are going to write about human extinction, we’d better start writing now.”

I have long believed that the main driver of human decline would be repeated pandemics. The pandemics themselves would not be the underlying cause. Rather, the declining health of humans would make us much more vulnerable to pandemics. We have seen this in the case of COVID-19 which has disproportionately sickened and killed those with underlying conditions such as diabetes, heart disease and cancer.

But these diseases are largely the product of a poor diet—derived from industrial agriculture and processed in ways that destroy nutrients and add empty calories—and exposure to a soup of dangerous man-made chemicals which circulate in our air, soil, water and food. Poor health has been achieved in rich countries in a time of plenty by essentially overfeeding and poisoning all of us and by addicting so many of us to a sedentary existence focused on mobile phones, computer screens and televisions. And, those in poor countries often get all of the poisons without much of the abundance. If they are poor enough, their malnutrition stems from simply not having enough food.

In addition, we’ve created a system for spreading pandemic viruses around the world that looks like something a virus would dream up if it could build an ideal habitat. Short of shutting down shipping, air travel, and long-distance motor vehicle travel, the system will continue to function as a superhighway for viruses.

The rejoinder to all of this is that it is not inevitable. Unlike plants and animals, humans have free will and can detect the peril they face and make adjustments. On current form humans are not actually exercising their free will in a way that will stop their own extinction. In fact, we are more like detritivores who feast on dead organic matter (fossil fuels), and when fossil fuels go away, we may, too—just like the iconic detritivore algae we call pond scum. The scum proliferates covering much of the pond after spring rains wash dead matter into the water. By summer the scum is almost gone after it consumes practically all the detritus that had been washed into the water.

Are we smarter collectively than pond scum? So far the answer is no. Whether the four horsemen of the apocalypse turn out to be low genetic variation, declining sperm quality, habitat loss, and pandemic disease won’t be known until it is too late. And, one observant paleontologist believes that it already is.

Image: “Destruction from The Course of Empire” (1836).  Thomas Cole via Wikimedia Commons.