Possible Titles
Eight Billion and One
The Effect of Human Life on the Planet in the Last 10,000 Years
Are Humans an Invasive Species
Climate Problem Caused by Too Many Humans
Summary: In a period of 10,000 years humans have grown from a probable worldwide population of 5 million to a now staggering 8 billion. All other Homo species (Homo Erectus, Homo Heidelbergensis, Homo Neanderthal) had only small populations which did not effect the population of other animals. The disappearance by 10,000 years ago of 86% of the megafauna species (animals over 50 kg) in Australia, 73% of the megafauna species in North America, and 79% in South America appears to coincide with the emergence of modern man from Africa. A sampling of the population of species remaining finds huge populations of five animals only. Modern man at 8 billion, and its favorite meals - cows, pigs, sheep, and water buffalo. Farming has led to this change in populations, which has likely led to the largest biomass of animal life in earth's history, with consequences to climate (which are widely debated).
The Prime Directive
In the TV series Star Trek Star Fleet had something called the Prime Directive, and that was not to interfere with a growing culture. This is referring to "intelligent" beings, so this would not apply to mammoths, mastodons, giant ground sloths, and so on, because they are not "intelligent" though elephants appear to recognize themselves in a mirror, which is taken to be a signature of intelligence. Humans since they appeared 200,000 years ago, have always observed their own wants, which I would call the Prime Meat Directive.
Climate requires a serious re-think, but where to start?
Climate at this moment in time appears to be a human population issue. It is not being caused by our distance from the sun, or from too much volcanic action. We're talking about habitat destruction, species extinction, rainforest deforestation, bleaching of corals, carbon dioxide heating up the planet - these are things caused by humans, and there's chatter about a sixth extinction that we ourselves are causing. And most of the people are nonchalant about it. Some day that may happen.
I guess beavers can cause a little deforestation, and elephants can take out lots of acacia trees which they love to eat, and certain insects can devastate whole populations of trees, but no animals create the forest devastation like humans for their own habitat. Actually, that would be an argument for the lumber industry. Send in the lumbermen to take down dry forests that will go to fire. That would be sensible thing to do, rather than see the lumber converted by fire to carbon dioxide.
Here's example of climate change caused by forces beyond human control. Every 20,000 years the Sahara becomes a green place, and then in another 20,000 years it becomes a desert again. That is caused by a change in the tilt of earth with respect to the sun, which moves the monsoons up to North Africa, and then down to the Congo. This is not what we are talking about. Those things are unavoidable.
How did we get here? Is modern man an invasive species?
It appears that the Homo species saw a dramatic DNA change about 200,000 years ago. Even Neanderthal, which may have had even a larger brain, did not seem to have the capabilities of modern man, so it appears something changed. Neanderthal used the same tools for hundreds of thousands of years. Modern man used those tools for a while, but they appear to have been more innovative. He will look for other ways of doing things. Much more sophisticated tools.
If we are living through a sixth extinction, and if it is being caused by humans, then this event began almost as soon as modern humans started exiting Africa 90,000 to 60,000 years ago because by 50,000 to 45,000 years ago 86% of the megafauna (animals over 50 kg) species disappeared from Australia. Poof, gone. Just like that.
So, if it were left to me, and I were to set a date for the Anthropocene era, I would use a date of 45,000 BCE for the beginning of its era because that is a date that can be set that appears to be a date where the effect of homo sapiens, the wipe out of large animals in Australia, can pretty much be a associated with them. There is no climate event or other predator that can be associated with it. I know a good lawyer would argue there isn't enough prima facie evidence, but it looks pretty damning. And I'm not sending anyone to prison, I'm setting up an intellectual date.
Consider this: from 13,000 to 8,000 years ago, 73% of the megafauna species in North America disappeared, and around this same time 79% of the megafauna species disappeared in South America. The Americas were a surprising cornucopia of animal life. One animal lost was the short-faced bear, perhaps the largest land mammal predator ever, something like half-again as large as our current largest bears, Kodiak or polar bears, perhaps twice as large. Other species wiped out in North America are still around (on other continents), such as the camel (which originated in North America, but went south to become the llama, and west to Asia), and the horse (it had to be re-introduced from Europe). Other amazing animals include the giant sloth, the mammoth, mastodon, smilodon (sabretooth tiger), two species of cheetah, the American lion (larger than the African lion), and the giant beaver. By between 13,000 and 8,000 years ago they all disappeared. Poof, gone, again! I came across these numbers originally in Peter Ward's book, The End of Evolution, but they are not a secret. It is pretty well known that for very large animals, it was essentially a 100% wipe out - mammoth, mastodon, great sloth.
Perhaps there is an optimal size for a predator. Man, wolf, dire wolf, hyena - they're 50 kg to 80 kg range. And these are all pack animals. Perhaps a single large animal is no match for a pack.
Meanwhile, in Europe mammalian species also started to disappear. Mammoth, mastodon, the Irish elk with its giant antlers, and many others, again 13,000 to 8,000 years ago. But among the species that disappeared one of the first to go was one of our own, our distant cousin, Neanderthal, approximately 40,000 years ago.
I imagine these early humans were like Ridley Scott's Alien. Maybe with limited language, maybe not. But very clever. They know all the animal tricks out there. They know that animals will go to a pool of water for a drink, and that's a good place to hunt a meal. They're preternaturally clever. We know from footprints in the White Sands of New Mexico that humans trailed the tracks of a Great Sloth 23,000 years ago. Maybe they know which animals leave which tracks. Maybe they don't have the Alien's extra teeth and tail, but they can fashion deadly stone tools and can use fire. [The actual animals which did the killing in North and South America were the paleo Indians, who are directly related to the present American Indians, who came over the Bering Straits land bridge. And who were decimated by European humans.]
If all of these species disappeared at the hand of modern man, it only took a handful. 10,000 years ago it is estimated that perhaps there were only 5 million humans or so on the planet. If you ever wondered what would happen when modern man no longer had to fear that some predator could kill them, you have your answer. In the short time of 10,000 years, with some good weather, and the advance of farming, we are now at 8 billion. Just what you might expect. Spectacular grow
But there are problems with this wipeout scenario:
It feels like there were too few humans to take out all of these many animals. That might be partially solved in North and South America by the presence of packs of dire wolves. But this does not solve Australia. Though it is thought that packs of humans (I say again, troops, or communities, of humans) burned a lot of vegetation in desert areas of Australia to corral some of these lumbering species, and this vegetation was so fragile, that it was never replaced or will be replaced. Thus began habitat loss.
And then there is the problem that has to be solved with respect to the dire wolf itself: why did it disappear? It has been suggested they were so successful they ran out of prey. That feels hard to believe.
Climate in the form of ice ages has been suggested as a cause for species loss, but the problem with that is so many of these animals made it through ice ages before, why should this past ice age be so special as to eliminate so many species?
But there are explanations. Nano-diamonds have been discovered, and it has been suggested that a Tunguska type asteroid exploded near a huge natural dam in Canada at the end of the ice age, unleashing a tidal wave of water, killing untold numbers of animals. The problem with this explanation is how does that explain the disappearance of megafauna in South America, and the much earlier wipe out in Australia?
It has been suggested a wave of fresh water came down to the Great Lakes and traveled east to the St. Lawrence instead of down the Mississippi. And that blast of fresh water overwhelmed the heavy salt water that goes down to the deep water conveyor, and that conveyor stopped, and weather changed dramatically, and that did a lot of the killing.
Work in biology has shown that large species are not often predated on, which calls into question why a large species like the mammoth and the mastodon disappeared at all. And especially, why would the short-faced bear, perhaps the largest mammal predator ever, disappear? Who would take it on?
These and other problems need to be solved, but at the end of it, it cannot be denied that with its clever stone tools, lighter spears, atlatls, the possible invention of bows and arrows, the use of fire, at the end of it sits the clever human, he'll mop up. But moreover, anything he feels is a challenge, he is prepared to take it on. And this is the essence of the Overkill Hypothesis of Paul Martin.
All of this should be sufficient proof of man's success as an invasive species. His success is astonishing, devastating. No other animal, so far as we know, has ever been this successful. He is a hunter without compare.
Meanwhile, back in Africa where man is not an invasive species...
The other part of the proof that man is an invasive species is okay, he invaded, but what happened where he developed, what happened in his native land? Humans evolved in Africa, but surprise, back there we still have a cornucopia of animals - hippopotamus, rhinoceros, lion, leopard, hyena, giraffe, camel, ostrich, elephant. Apparently, these animals understood to stay away from the bipedal ape. But on the other continents, they were completely unaware that this small, bipedal, apparently harmless animal, is really a killer.
Of course, even in Africa things have changed with the advent of farming. Wild Africa is disappearing. Farmers will not put up with pests, even if they are elephant-sized. So, all of these species are in trouble. Perhaps sample populations can be maintained in zoos. And at the very least you can save the DNA. You don't have to worry because they don't have cultures. There is no such thing as elephant culture, or is there?
Humans appear to have given absolutely no consideration to any other species (except possibly dogs who accompanied them on hunting expeditions) until now when we are suddenly worried about whether other species will disappear. And we also wonder a little bit about how the whole ecosystem works. We're a little worried about runaway green house gases, but probably not enough. We are so little concerned with other species, that it should be no big surprise that Stephen Hawking warned against alerting extra terrestrial species of our existence. If an invasive species treated us with anything like the disregard we have treated whole continents, we will be goners.
It does not appear, even now, that man understands his role in the ecosystem, because he does not appear to understand the ecosystem. Seemingly intelligent people like Elon Musk are still talking about increasing the population. But just in case, Musk wants to have a colony on Mars. He does not appear to have a clue about ecosystems. Even 5 million is a lot of humans. Because that small population of 5 million may have destroyed roughly 75% of large species on three continents.
But predators do have an important role, and not always sinister, and I believe that includes humans. We begin to understand a little about the ecosystem through the work of Robert T. Paine, who wrote about the concept of keystone species beginning in 1969. Keystone species are species that have an inordinate effect in a particular ecosystem. Some of the keystone species are organizers, like the beaver, grazers like the Wildebeest, pollinators like bees (now experiencing bee collapse syndrome). Predators have a role, too. African spotted dogs are a keystone species. Without a predator like this, the ruminants multiply like crazy with antelope and deer and kudu are everywhere devastating grasslands and forests. Without the starfish, mussel populations go out of control, and kelp forests disappear. Without wolves, elk will eat everything in sight, and you can see exactly what it didn't eat - everything above its head. New trees can't grow, they are eaten early on.
It seems that our economy, which is totally based on the growth of the human population, may need to be revamped completely. The question becomes something like: how much of the rain forest and the coral will need to be destroyed before humans come to understand their place in the ecosystem?
Perhaps it will take an act of imagination. If we imagine all other animals as slave populations, we may develop more compassion for them. That maybe consciousness is not a binary proposition, but a spectrum thing. Maybe other species do not have our capacity for introspection, but they are certainly conscious to the extent that they are aware of their limbs, their surroundings and feel pain.
Higher monetary values need to be placed somehow on population decline. And the thing is, you can tap unlimited amounts of energy with fusion, but how does that help solve our problems with human carbon-based ecology? Then you have deep thinkers like the investment adviser, Jeremy Grantham, who is wont to explain that there is an absolute limit to life - the amount of phosphate. Phosphate is critical to A-T-P which is the molecule that provides the cellular energy which powers the whole apparatus of life. There are large but not infinite deposits in Morocco.
But maybe we don't have to worry about the carbon-based world as we transition intelligence to our AI creations, which are not so much based on the carbon world, so far, but on silicon (which sits below carbon on the chemical chart).
You sense humans are the problem the instant you hear the words - habitat destruction. Other animals are capable of habitat destruction. Elephants can take to acacia trees to the extent of making them disappear. But they don't compare to a real estate developer and a plot of land. Giant parks like Yellowstone or Gorongosa, large as they are, are apparently not large enough for animals like elephants and giraffes and rhinoceros. Yellowstone needs to be linked to other parks to create a long park extending into Canada to give the Grizzly bear sufficient territory.
I have no idea of what might be the proper balance on the planet. It will always be in flux. We are only just learning about the importance of keystone species. The facts seem to suggest that even a few million people with stone tools are devastating enough. So, while modern man is a keystone species, it has moved right past that into a controlling species. Has this human species obtained enough wisdom so that even a hundred million, or a billion, can live in tune with the rest of the planet? How much of the land can safely be organized into farms?
Humans and Their Favorite Meals
Consider what the chart below might look like if humans had not advanced beyond Homo Erectus, an animal which did not have an outsized population. It is easy to see that humans have created large populations of animals which are favorite meal selections. We see large populations for cows, sheep, and pigs. (Not included are 33 billion chickens, which are not mammals.) What would the population of horses and donkeys and mules be if horses had not been used by humans for travel and donkeys used for farm work? Not to mention the 1.5 billion pets (dogs - 900 million, cats - 600 million). And what if you are not a favorite meal? Man hunted whales nearly to extinction for its oil for lighting, and buffalo (30 million before Europeans, now 400 thousand) were sometimes killed just to keep them off train tracks, and dolphins (and fish) have adversely been effected by the devastating human bottom trawling fishing techniques.
Without humans in the picture, there would be more elephants and whales and wolves. Think of 1800 when the human population was only 1 billion. In America, there was a vast wild west, mostly occupied by Indians and buffalo. The balance of species would be different all up and down this chart. And as economists would say, there would be multiplier effects: how would larger wolf populations affect deer and elk? It is hard to imagine a species not effected by human hunting, farming and fishing. Perhaps zoological archaeologists may be able to give us the numbers of species a million years ago when no Homo species was a threat. Perhaps they can be aided by climate archaeologists (think ice cores), who can tell us what the atmosphere looked like. We don't know. I sense that the population of modern humans is way out of whack with what the planet can cope with. But humans have done remarkable things - we've been able to plug a leak in the ozone, though it may take a lot more to stop the temperature of the planet to keep from increasing untenable levels, removing carbon dioxide. I sense that we have only begun to see how the climate change may affect things. During the Permian, the burning of coal in the Siberian traps increased the temperature by 5 degrees, but that was enough to warm up the oceans, and that freed up methane frozen at the bottom of oceans and in the permafrost added another 5 degrees, and this didn't take as long. 10 degrees was enough to eliminate 95% of life (of all kinds).
We have to remember that the planet is ever changing. To start out, it was a burning cinder. About 717 million years ago the planet was entirely encased in ice, and that continued for 5 million years. This I dredge up to remind us that the planet is always in flux, it is not static like Mars, for example. So far, anyway. So, I am not clear what our parameters should be.
If a super-predator with language was not multiplying like bacteria, there would be no discussion of biodiversity or habitat destruction. There would be no language to discuss it with, for one thing, and there would be no huge human population and its very large entourage to cause those things.
There is something odd about the chart below of mammal populations. Usually, predator populations are some smaller subset of the prey population, yet human population is almost twice the rest of all these other animal populations.
Humans have achieved great feats of intellectual prowess. Newton and gravity. Maxwell and electricity. Einstein and gravity again. Quantum Mechanics. Darwin's insights. Bach's music. Shakespeare's insights and language. Countless remarkable achievements. I am in awe of them. But it seems we are still learning our place in the scheme of things. We know now, for example, that the Sun does not orbit the Earth, a human-centric view of things. And maybe that is a good model for what I am talking about - man's place in the ecosystem. The Earth is a much smaller body moving around a much, much larger body, the Sun. It may not be possible to figure out exactly what man's role should be, but I think he can do a lot better than he is doing now.
Human birth may still be a miracle, because getting that huge head through the birth canal is very difficult, and enormously painful, but these days you can hardly claim that it is a rare thing. Not with 8 billion births. Not when human population is something like twice all of the other mammals on the chart.
What is the worst we are looking at in the way of climate consequences? I suspect it is something more like Venus than Mars, which has a runaway green house gas problem. Our planet is concerned with greenhouse gases, but this concern is tempered by politics. Some things are hard to prove in a system as large as the earth, and impossible to prove to a politician with a following
All I did was do Google searches on animals I thought would be over 50 kg., so I may have missed a few.
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Mammal Populations |
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Megafauna (50
kg+) |
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Humans 2022 CE |
8,000,000,000 |
Favorite favorite |
|
|
Cows |
1,500,000,000 |
Favorite food |
|
|
Sheep |
1,000,000,000 |
Favorite food |
|
|
Goats |
1,000,000,000 |
Favorite food |
|
|
Pigs |
677,000,000 |
Favorite food |
|
|
Water Buffalo |
208,000,000 |
Favorite food |
|
|
Horses |
60,000,000 |
Useful for transport |
|
|
Kangaroos |
48,000,000 |
||
|
Donkeys |
40,000,000 |
Useful for farming |
|
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Deer |
30,000,000 |
||
|
Antelope |
28,900,000 |
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Mules |
10,000,000 |
Useful for farming |
|
|
Dolphins |
8,000,000 |
||
|
Kudu |
5,790,000 |
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Caribou |
5,000,000 |
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Humans 8000 BCE |
5,000,000 |
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Monkeys |
1,500,000 |
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Whales |
1,500,000 |
Oil useful for lighting |
|
|
Wildebeest |
1,500,000 |
||
|
Bears |
1,221,000 |
||
|
Elk |
1,000,000 |
||
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Moose |
830,000 |
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Zebras |
750,000 |
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Elephants |
450,000 |
Ivory |
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Bison |
440,000 |
Favorite food |
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Leopards |
250,000 |
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Chimpanzees |
218,000 |
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Wolves |
225,000 |
Pest |
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Hippopotamus |
122,500 |
Favorite sport kill |
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Gorillas |
101,500 |
||
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Giraffe |
69,000 |
||
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Orangutans |
57,500 |
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Hyenas |
37,000 |
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Rhinoceros |
27,000 |
Ivory |
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Lions |
20,000 |
Favorite sport kill |
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Cheetahs |
6,750 |
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Tigers |
4,500 |
Favorite sport kill |
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4,636,019,750 |
Total Non-human Mammals |
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12,385,000,000 |
Top 6, including humans |
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12,636,019,750 |
Total Mammal Megafauna 50 kg/110 lbs |
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251,019,750 |
Leftover after the Top 6 |
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