Add all of us up, all 7 billion human beings on earth, and clumped together we weigh roughly 750 billion pounds. That, says Harvard biologist E.O. Wilson, is more than 100 times the biomass of any large animal that’s ever walked the Earth. And we’re still multiplying. Most demographers say we will hit 9 billion before we peak, and what happens then?
Well, we’ve waxed. So we can wane. Let’s just hope we wane gently. Because once in our history, 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. Forty? Come on, that can’t be right. Well, the technical term is 40 “breeding pairs” (children not included). More likely there was a drastic dip and then 5,000 to 10,000 bedraggled Homo sapiens struggled together in pitiful little clumps hunting and gathering for thousands of years until, in the late Stone Age, we humans began to recover. But for a time there, says science writer Sam Kean, “We damn near went extinct.”
I’d never heard of this almost-blinking-out. That’s because I’d never heard of Toba, the “supervolcano.” It’s not a myth. While details may vary, Toba happened.
Toba, The Supervolcano
Once upon a time, says Sam, around 70,000 B.C., a volcano called Toba, on Sumatra, in Indonesia went off, blowing roughly 650 miles of vaporized rock into the air. It is the largest volcanic eruption we know of, dwarfing everything else…
That eruption dropped roughly six centimeters of ash – the layer can still be seen on land – over all of South Asia, the Indian Ocean, the Arabian and South China Sea. According to the Volcanic Explosivity Index, the Toba eruption scored an “8”, which translates to “mega-colossal” – that’s two orders of magnitude greater than the largest volcanic eruption in historic times at Mount Tambora in Indonesia, which caused the 1816 “Year Without a Summer” in the northern hemisphere.
With so much ash, dust and vapor in the air, Sam Kean says it’s a safe guess that Toba “dimmed the sun for six years, disrupted seasonal rains, choked off streams and scattered whole cubic miles of hot ash (imagine wading through a giant ashtray) across acres and acres of plants.” Berries, fruits, trees, African game became scarce; early humans, living in East Africa just across the Indian Ocean from Mount Toba, probably starved, or at least, he says, “It’s not hard to imagine the population plummeting.”
Then – and this is more a conjectural, based on arguable evidence – an already cool Earth got colder. The world was having an ice age 70,000 years ago, and all that dust hanging in the atmosphere may have bounced warming sunshine back into space. Sam Kean writes “There’s in fact evidence that the average temperature dropped 20-plus degrees in some spots,” after which the great grassy plains of Africa may have shrunk way back, keeping the small bands of humans small and hungry for hundreds, if not thousands of more years.
So we almost vanished. But now we’re back.
It didn’t happen right away. It took almost 200,000 years to reach our first billion (that was in 1804), but now we’re on a fantastic growth spurt, to 3 billion by 1960, another billion almost every 13 years since then, till by October, 2011, we zipped past the 7 billion marker, says writer David Quammen, “like it was a “Welcome to Kansas” sign on the highway.”
In his new book Spillover, Quamman writes: We’re unique in the history of mammals. We’re unique in this history of vertebrates. The fossil record shows that no other species of large-bodied beast – above the size of an ant, say or an Antarctic krill – has ever achieved anything like such abundance as the abundance of humans on Earth right now.
But our looming weight makes us vulnerable, vulnerable to viruses that were once isolated deep in forests and mountains, but are now bumping into humans, vulnerable to climate change, vulnerable to armies fighting over scarce resources. The lesson of Toba the Supervolcano is that there is nothing inevitable about our domination of the world. With a little bad luck, we can go too.
We once almost did. Terry W. Colvin Ladphrao (Bangkok), Thailand Pran Buri (Hua Hin), Thailand http://terrycolvin.freewebsites.com/
I hadn’t heard of this specifically, but I think I read about theories of a population bottleneck sometime around then, which perhaps explains the remarkable lack of genetic diversity in the human species. (It’s perhaps the evolutionary version of the CMB). John Crisp.
Toba extinction (I thought was still in the realm of possibilities) has been indicated as a crucial step in the sapiens evolution. We are almost sure the sapiens population (from genetical studies in modern populations) dropped to a number of thousands at that time, probably because of the Toba eruption and/or for climate changes.
What is really strange is that about 20.000 years later the sapiens started for the firt time
to paint on the walls of caves. What happened 50.000 years ago, after the almost extinction of the sapiens?
Why the sapiens, with a larger population, didn’t try to paint on caves before this age?
I can’t believe it has been just cultural evolution. We met another homo species 50.000 years ago, coming from Africa, in the Middle East and we know almost for sure we carry some its genes in our genoma. Is it possible in this “cross” we had a mutation in a small population that changed in some subtle way our brains? Maybe we developed the secondary languages cortex areas that today we use to learn non native languages after the age of 3? G. Vitillaro.
On the other hand our species does represent some way the universe has to observe and understand itself. I don’t know if Neanderthals would have evolved or risen to that occasion I don’t know if there is some underlying metaphysical necessity for intelligent life similar to ourselves. If not then it all seems like a waste. However, in a few million years the Earth will be back to normal operation and return to health after we have gone the way of extinction.
A lot of this comes down to shit happens. There is not too much point getting overly emotional about the wax job we are doing on the planet. First off it does not do anything to change the situation and it only makes life suck more. LC
EO Wilson makes the same observation I make to people in conversations; at no time in the natural history of this planet has there been a species our size and dietary requirements that numbered 7 billion at one time. Our impact on the planet increases several dozen times over when one considers the resources we take. The human species is heading for a bottleneck. The Toba volcano appears to have forced our species through a bottleneck 70,000 years ago, and 150,000 years ago our species appears to have emerged from some bottleneck in the evolution of some hominid population. The current energy intensive socio-economic structure we live in will exhaust its stores of thermodynamic free energy and the entropy impact we have had on the planet will collapse our population to a very small percentage of its current number. The greater the damage we do to the planet the smaller the human remnant population will be that passes through the future bottleneck. LC
We humans are biological misfits. In most social animal groups alpha members have the greatest access to sex and passing on of genes. The dominant members of human societies acquire material wealth, but as a rule they have few progeny, and in some cases they end up with their heads under guillotines and raised up on spikes. The aristocratic families of Europe in the 19th century simply fizzled out as much as they lost power. In addition dominant social human groups tend to inbreed, which leads to founder effects. Analysis of Egyptian mummies illustrates a preponderance of congenital defects, and this exists with members of each dynasty examined. A body examined in Leicester England is possibly the body of Richard III the last Plantagenet king of England. The body bears congenital problems attributed to that king. The rich and powerful tend to strangle their biological future or their ability to play on the evolutionary game table.
I know an Hispanic woman whose great grandfather sired 10 children and is the direct descendent of over 150 people in an extended family. If we do the halving of genes with each generation this person amplified his genes by a factor of 18. Compare that to the uber-rich who often either have no children or if they do only have one or two, where this can persist with their own progeny. Darwin does not smile fondly upon the the rich and powerful. The Bible might have something right when it says the meek shall inherit the Earth. If you amplify your genes by a large factor several generations into the future you load the dice in your favor that your genes will make it through the bottleneck. LC
That is a possibility. Of course it depends upon what we mean by bottleneck. The implosion humanity might face towards the middle or end of this century could reduce our population from a projected peak of 9 billion down to less than a billion. If you have 10 children now you stand a reasonable chance your genes will make it through that. If your children all have large families your chances are very good. If the implosion of humanity stops at that point then certain cultural elements will probably survive, maybe even some of our great works will remain in some record. It is difficult to know what conditions will be like on this planet after then. A collapse of the global biome or planetary biosphere will likely mean the human population will continue to decline for some time afterwards. A real bottleneck means humanity is reduced to maybe several million, or maybe a few pockets of populations numbering in the thousands. In that case cultural elements will be erased, which includes religions like Catholicism with its huge numbers and Mormonism, and the probability that any of our genes pass through that sort of bottleneck are vanishingly small. Even the most fecund person today might only improve their chances by multiplying a tiny probability by 10 or so. LC
‘Wealth in the modern world resulted from a combination of individual efforts. In spite of the great importance in our national life of the…ingenuity of unusual individuals, the people in the mass have inevitably helped to make larger fortunes possible.’ Franklin D. Roosevelt.
I guess that the descendants of the Koch brothers might possibly make it through that bottleneck, just because they might be the last to lose the resources that the rest of the rabble have. Bill Jefferys
I imagine Tsar Nicholas thought so, up to 1917. Ugly. Indeed. kerry
When we collapse this planet’s life support system the parasites can be made into dinner. Without an environmental life support system there will be in the end nothing left to eat except each other. So with our superior military we can conquer other nations and use the people as livestock to be converted into hum-burgers. Domestically we can clean things up as well, the homeless, the welfare queen and so forth will be made into Soylent Green. Of course once a population or species starts cannibalizing itself a collapse is certain and extinction possible. It just might be that the future’s wealthiest man in the world might be the last man to eat a square meal — of hum-burgers. LC