The End of the Road?

In the early history of humanity there were a couple of instances where our species came close to disappearing.  Yet we hung on and tens of thousands of years later we reached  a staggering one billion in number. That's usually pegged at around 1814.

Lo and behold, in barely two more centuries we've grown to 8 billion. We've accompanied growth in raw numbers with considerable increases in longevity and per capita consumption. We define profligacy.

There are several ways to put this. Easy come, easy go. What goes up must come down. All good things must end. You get the idea. It looks like we've burned out planet Earth.

There are those among us who study this sort of thing, especially paleontologists. One of these is Henry Gee, paleontologist, evolutionary biologist and editor at the journal Nature. He says we're on the way out, the express train to extinction, sooner rather than later.

Mammal species tend to come and go rather rapidly, appearing, flourishing and disappearing in a million years or so. The fossil record indicates that Homo sapiens has been around for 315,000 years or so, but for most of that time, the species was rare—so rare, in fact, that it came close to extinction, perhaps more than once. Thus were sown the seeds of humanity’s doom: the current population has grown, very rapidly, from something much smaller. The result is that, as a species, H. sapiens is extraordinarily samey. There is more genetic variation in a few troupes of wild chimpanzees than in the entire human population. Lack of genetic variation is never good for species survival.

What is more, over the past few decades, the quality of human sperm has declined massively, possibly leading to lower birth rates, for reasons nobody is really sure about. Pollution—a by-product of human degradation of the environment—is one possible factor. Another might be stress, which, I suggest, could be triggered by living in close proximity to other people for a long period. For most of human evolution, people rode light on the land, living in scattered bands. The habit of living in cities, practically on top of one another (literally so, in an apartment block) is a very recent habit.

The Worm Turns

Politicians strive for relentless economic growth, but this is not sustainable in a world where resources are finite. H. sapiens already sequesters between 25 and 40 percent of net primary productivity—that is, the organic matter that plants create out of air, water and sunshine. As well as being bad news for the millions of other species on our planet that rely on this matter, such sequestration might be having deleterious effects on human economic prospects. People nowadays have to work harder and longer to maintain the standards of living enjoyed by their parents, if such standards are even obtainable. Indeed, there is growing evidence that economic productivity has stalled or even declined globally in the past 20 years. One result could be that people are putting off having children, perhaps so long that their own fertility starts to decline.

The most insidious threat to humankind is something called “extinction debt.” 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 cause of extinction is usually a delayed reaction to habitat loss. The species most at risk are those that dominate particular habitat patches at the expense of others, who tend to migrate elsewhere, and are therefore spread more thinly. Humans occupy more or less the whole planet, and with our sequestration of a large wedge of the productivity of this planetwide habitat patch, we are dominant within it. H. sapiens might therefore already be a dead species walking.

The signs are already there for those willing to see them. When the habitat becomes degraded such that there are fewer resources to go around; when fertility starts to decline; when the birth rate sinks below the death rate; and when genetic resources are limited—the only way is down. The question is “How fast?”

I suspect that the human population is set not just for shrinkage but collapse—and soon.  If we are going to write about human extinction, we’d better start writing now.

At least our leaders have the good graces not to bother us with these pesky details. After all, who wants to debate the declining quality of human sperm?  Not me, brother.

I wish Henry Gee's dystopian view was an outlier. It's not.

We are now firmly in the grip of Overshoot. It looks like this:

We have exceeded Earth's ecological carrying capacity. There are way too many humans living way too long and consuming vastly more resources than Earth can provide.

Some years ago, while we were still short of 8 billion, I discussed  the problem with a researcher at the Global Footprint Network (NGO).  She said we crossed into Overshoot in the early 70s when humanity reached 3.5 billion. In our biosphere's current degradaded state she estimated Earth can now sustainably provide for 2 billion, max. Do the math. We're at 8 billion. Does that sound like the formula for collapse?

Comment Response -

Lungta - if you take a timeline of 315,000 years, the changes we have wrought in the last two centuries are almost unbelievably fast. It is a metastasis and we seem to imagine that going from a two pack a day habit to three packs a day will solve our problems.

Lorne - those whom the gods would destroy they first make mad.

Gordie - define "killing people." I sense that you mean we must not blow them up but extinction by other causes is okay, not our problem. That's taking the notion of collateral damage to a grotesque extreme.