Human Extinction?
Extinction occurs when species are diminished because of environmental forces (natural disaster, overexploitation of resources) or because of evolutionary changes in their members (genetic inbreeding, poor reproduction).
Given the definition above, British paleontologist Henry Gee, thinks that we qualify for being on the road to extinction. As an evolutionary biologist and editor at Nature his opinion is worthy of consideration, unlike the human extinction “doomers”. This essay is my “debate” with myself about his ideas.
To begin, let’s accept the fact that most of have never thought of human extinction, and if you saw it on the internet, thought the people who thought like that as deranged as Flat Earthers or those who believer Elvis is still alive. When we do consider extinction we probably imagine the dinosaur extinction. Perhaps an image like this flashes in your mind:
Until yesterday, I too totally rejected the view that our current behaviours [climate change, species extinction, mental illness/addictions] and genetic problems [ie. small genetic variation, plummeting sperm quality], could lead to our extinction. Quite frankly I have found these “doomers” or “near term human extinction” believers to be ridiculous and deranged. Extinction is what happens to other species – we are “special”. We are so smart it could never happen to us. However, thinking more in the long term, as Henry Gee does, has opened me up a whole other perspective. I now look at our current over-exploitation of the world’s resources and our obvious decreasing social/physical/mental health as indicators that we, at a minimum at risk of, long term extinction. Take a read of Gee’s argument and then we will continue with this debate.
As a paleontologist, I take the long view. 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 DNA is extraordinarily the same. 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. Another reason for the downturn in population growth is economic. 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.
https://www.scientificamerican.com/article/humans-are-doomed-to-go-extinct/?fbclid=IwAR0mQJvQb6xTNxXIDwTgWDxgdVt0e0UwYyVRUe-YwvOcFjeWxIwcIlAm_q0 You may enjoy his latest book is A (Very) Short History of Life on Earth (St. Martin’s Press, 2021).
I decided to research Gee’s statement that humans have almost gone extinct several times in the past – in other words – we not really a biologically successful species, as these near extinction events tell us that were never “destined for greatness” and that our reduced gene pool makes our future dubious at best. Here are two such near extinction events.
Around 75,000 years ago, the Toba volcano in Indonesia erupted. According to scientists, this volcanic eruption was the largest in two million years. It is said that around 3,000 cubic kilometers of ash was released during the event which unleashed millions of light blocking particles in the atmosphere killing plants and trees. A study reveals that almost the entire human population became extinct as there was no rainfall and an acute shortage of food was created due to the catastrophe. It is speculated that the thick vapors from the volcanic ash caused a global ‘volcanic winter’ of ten years. The world-wide population of human beings skidded so sharply we were down to roughly a thousand reproductive adults. One study says we hit as low as 40.
New genetic findings suggest that early humans living about one million years ago were extremely close to extinction. The genetic evidence suggests that the effective population—an indicator of genetic diversity—of early human species back then, including Homo erectus, H. ergaster and archaic H. sapiens, was about 18,500 individuals (it is thought that modern humans evolved from H. erectus), says Lynn Jorde, a human geneticist at the University of Utah in Salt Lake City. That figure translates into a total population of 55,500 individuals, tops. One might assume that hominin numbers were expanding at that time as fossil evidence shows that members of our Homo genus were spreading across Africa, Asia and Europe, Jorde says. But the current study by Jorde and his colleagues suggests instead that the population and, thus its genetic diversity, faced a major setback about one million years ago.
Where I disagree with Gee is his unstated but clear deterministic worldview. He clearly does not see that free will and choice as relevant. He also does not consider that we could evolve into another, “more human” species. He only proposes that we are a dead end. I disagree that this is a foregone conclusion, at least not for a very long time. I will agree that it is a distinct possibility, which I did not before. I can now even agree that near term extinction is a possibility – if we are stupid enough. So, perhaps, Mother Nature is just testing us? Perhaps all our “crises” are simply Mother Nature putting us into the crucible and then into the fire to see if truly are worthy of the name “home sapiens”?
I leave you with this is a quote from a letter from blog of Matthieu Ricard, a Buddhist monk, who comments are not about extinction, but a factor that is a significant part of that possible human future: our unwillingness to use one of the major advantages of our “intelligence” – the ability to imagine the future and take action today to change it so as to avoid pain and suffering.
How can we not feel concern for the fate of our children, our grand-children and those who will follow suit ? They’ll say : « you knew and you did nothing. » This bargaining and procrastinating stance from the highest polluting countries is pathetic. Do you bargain with the doctor who only gives your child half the medicine needed to treat septicemia ? Do you bargain with the surgeon who only takes out half of the tumor threatening to take over your body ?
An advisor from the Saudi Ministry of Oil demanded sentences such as « the need for urgent and fast-tracked mitigating actions at all levels… » be removed from the report. A high-ranking official from the Australian government rejected the conclusion that shutting down coal-fired power plants is necessary, even though one of the objectives of the COP26 is to end coal use. India announced it was aiming for carbon neutrality in…2070. Meaning never, since many irreversible changes will have taken place in the interval. Coal is responsible for almost 40% of yearly CO² emissions, putting it center stage in the drive to meet the 1,5°C target. To reach this goal, global emissions must be slashed by 45% by 2030 and near zero at mid-century.
The draft report stated that « plant-based diets can reduce greenhouse gas emissions by up to 50% compared to the average high-emission western-style diet ». Brazil and Argentina, two of the world’s largest producers of cattle and animal-feed crops, firmly opposed including in the final report data that showed that a reduction in meat consumption is necessary to cut down greenhouse gas emissions. Isn’t it absurd that lobbyists from fossil fuel industries formed the largest delegation at the COP26 ? Our future is at stake – we either suffer a little now, or a lot more later – and right now it looks like we have chosen the path of greater future pain.
If we were truly homo sapiens, which we appear not to be when we look at our actions objectively, we would act decisively now. But we are not. So, sadly, perhaps all this talk of extinction is more than just theory. However, in spite of this, I not throwing in the towel. I will never give up. That human part of me, the unwillingness to accept death without a good fight, is alive and well – and I hope it for you too.
A final point. Considering unpleasant topics like this should never be seen as pessimistic – quite the opposite – IF done to make changes NOW to avoid these nasty futures. Consider this scenario planning, no more. In fact, only very recently in human history did people realize that Homo sapiens, and everything it finds meaningful, might permanently disappear. Only recently did people realize the physical universe could continue — aimlessly — without us. However, this was one of the most important discoveries humans have ever made. It is perhaps one of our crowning achievements. Why? Because we can only become truly responsible for ourselves when we fully realize what is at stake.
References
https://thereader.mitpress.mit.edu/how-humanity-discovered-its-possible-extinction-timeline/
https://www.scientificamerican.com/article/early-human-population-size-genetic-diversity/
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