Hi, I'm John Green, welcome to Crash Course Big History. Today, we're gonna be talking
about the spread of human foragers across the world and the start of the agrarian era.
Mr. Green, Mr. Green! Didn't we study all that agrarian stuff in World History, because
I'm a very busy person, I don't wanna do it again.
Yeah, a couple things, Me From the Past, first off, playing Zelda alone in your basement
does not constitute being busy. Also, in Crash Course World History, we zoomed through a
lot of this stuff, because we wanted to get to, like, the real history-ish parts of history,
you know, the parts with the funny hats and the Mongols. [Mongoltage]
But if it weren't for agriculture and the surpluses that came with it, we never would
have had funny hats. That's why we study Big History.
[Theme Music]
So as mentioned last week, humans anatomically similar to us have been around for about 200
or 250 thousand years. Like, here's a picture of one of the oldest known fossil remains
of our species from Ethiopia, dated to approximately 195,000 years ago. For the vast, vast majority
of our existence, homo sapiens were hunter-gatherers, like farming, civilization, modernity, all
of that happened in the last 10-15,000 years. And you'll remember that the eruption of Mount
Toba about 74,000 years ago reduced the human population to a few thousand, and that scrappy
group of survivors held on, and for the next 60,000 years, human populations migrated over
the world, separating into their own little petri dishes. And that was interesting, because
the human experiment could proceed in isolation in several different zones in the world: the
Afro-Eurasian, the Americas, Australasia, and the Pacific. And this was really useful,
because it allowed each of those world zones to develop their own distinct brand of football,
which makes for such a beautiful game today, apparently there was no football back then.
Really? What did they do all day?
Apparently they were hunting and gathering.
Okay, so by 11,000 years ago, the human population had recovered from the Mount Toba disaster
and grown to about 6 to 8 million people. Now, because foraging requires humans to constantly
move on to new ecosystems to find food while the old ones regrow and replenish themselves,
6 to 8 million is about the largest population of foragers that the entire surface of the earth could support.
Now you may remember in the very first episode of Crash Course World History we talked about
the mystery of why humans developed agriculture even though foraging is easier. One theory
involves so-called Gardens of Eden, where the warming climate of the earth created some
lush ecosystems with enough food for foragers to quit migrating and settle down for several generations.
The Natufians of what later became the Fertile Crescent in the middle east hunted
gazelles and fished and harvested wild grains, but they weren't really farmers. But then
after a few generations of vigorous population growth, food started to grow scarce in these
Gardens of Eden. Given their new relatively sedentary lifestyle, those humans may have forgotten
how to forage effectively. Also, surrounding areas may have been already overpopulated
with other foragers. So humans had to choose between starving to death and getting more
out of the land that they were currently on -- a choice that historically we make by trying not to die.
These humans already had a deep knowledge of plants and animals, and if you've got
organisms nearby that might be useful to domesticate like wheat or goats or wild pigs - bingo, agriculture!
Now of course there are also many other theories about why agriculture emerged around the world
but regardless, agriculture represents a massive shift in human activity. Hunter-gatherers
adapted themselves to the resources provided by the environment, right? But agriculturalists
increasingly adapted the environment to suit their needs. Forcing the environment to adapt to humans
became an increasingly big deal until, you know, like today when it is arguably the biggest deal of all.
Now, all that being said, the advent of agriculture didn't, like, immediately lead to wars and
cities and kings and funny hats. In fact another 5000 years would pass before the first states
emerged. So for the first half of the agrarian era, humans lived in a world of villages with
transient herders and foragers in the gaps between.
Giving up foraging and settling down did have some downsides in the form of backbreaking
labor and diseases moving easily among denser and more numerous populations, but farming
allowed humans to support a much larger number of people within a much smaller land area
than foraging. This was very good for collective learning, which relies on both the number
of potential innovators and the close connectivity between them. The world population had grown
from roughly 6 million people at the beginning of agriculture to 50 million by the emergence
of states 5000 years ago - roughly 5000 times the size of the population that survived the
Mount Toba disaster 70,000 years prior.
And because early farmers didn't really understand or have the technology to solve the problem
of pooping near the drinking water, another upside was that we invented alcohol which
was safer to drink instead. So the next time you see a person looking fancy with a glass
of champagne, just remember, it's a tradition that started from there being too much poop
in the water, and ever since has fueled millions of bad decisions.
States did eventually appear but not all states emerged at once, any more than all agriculture
emerged at once. Agriculture first emerged in the Fertile Crescent in Egypt around 11,000
years ago and then in east Asia and Papua New Guinea around 9,000 years ago. Agriculture
emerged in west Africa and the Americas around 5,000 years ago, though estimates definitely
vary for the Americas. Accordingly, the first states to arise were in the middle east where
agriculture first emerged, followed shortly by the Chinese and Indus Valley Civilizations.
Papua New Guinea may have invented agriculture around the same time but they never developed
enough agricultural surplus to support states. So yeah, in every world zone the invention
of agriculture was a precursor for the rise of states.
The key to having a state is agrarian surplus. If you produce enough food, you can have a
class of people who don't need to farm. They can then fulfill other duties in this increasingly
numerous and complex society whether they be leaders or judges who settle disputes,
bureaucrats who deal with administration, and infrastructure doctors who heal the sick,
priests who make sacrifices to vengeful gods or soldiers who provide security or at least
extract a portion of the agricultural surplus for the leadership through some kind of taxation.
And with more people filling new jobs and generating new ideas about them, this is also
good news for collective learning. Diversification of labor is also the first step of early states
toward hierarchies and classes - aristocrats and popular and despotic kings and pharaohs
and sultans, shahs and emperors. It also meant the first divisions into unequal, unfair,
and undemocratic hierarchies dividing man from man, man from woman, and the high from the low.
All of this brings us back to the Hobbes verses Rousseau debate. Hobbes viewed life without
state control as nasty, brutish, and short, while Rousseau viewed humanity as largely
egalitarian before claims to land and wealth and property corrupted them. Now certainly
the idea of an Age of Innocence or a Golden Age has been popular with many philosophers
and political idealists throughout history. I mean, if humanity had once been perfect
and was simply corrupted by societal structures or political systems, then it would take only
a few tweaks or reforms to get us back to perfection. Unfortunately, it now seems clear
that a lot of humanity's evils are created simply by the bad wiring of our evolutionary
biology, and the solution to that problem is somewhat complicated. It's very difficult
for me to imagine a world in which humans will say, "You know what? If the Earth can
only support 6-8 million foragers, then there should only be 6-8 million of us." So where
you stand on this Hobbes v. Rousseau question affects your view of the entire 250,000 years
of human history, and also your view about much of human morality, character, and potential.
Another Big History take on agriculture is this: Consider the sun. We are made up of
the leftovers of its formation and the debris of stars that came before it, but its role
in our history doesn't stop there. Fusion reactions happen in the sun's core. This generates
energy, which is released into space and takes approximately eight minutes to get to us.
Here on Earth, plants capture that energy and store it via photosynthesis. Agriculture
lets one species, us, harness more of that energy, we either eat it or we use it to feed
animals that we eat, or we use it to feed animals like horses and oxen that pull carts and carry burdens,
providing 500-750 watts of power, about 10 times more than what a human being could do.
So essentially, agriculture is the act of harnessing more energy from the sun, way more
than we could as foragers. All of this leads to an interesting perspective: human history
has frequently been viewed as too chaotic or complex to allow us to find an underlying
trend, a bottom line or overarching theme. And this to some people makes conventional
history differ greatly from the natural sciences. However, given what we know of energy and
complexity, consider the following: If we want to prevent our bodily complexity, as
well as the complexity that we have created, from descending into chaos, we must keep harvesting
matter and energy flows on a regular basis. This is the bottom line of human history.
I will therefore argue that during most, if not all, of human history, the quest for sufficient
matter and energy to survive and reproduce has been the overriding theme.
That doesn't mean that the bottom line is all there is to human history. You've got
political history and the history of warfare and gender history, class history, art history,
environmental history, oral traditions, creation myths, and much, much more, but none of those
would matter if we were all dead. If you don't eat, if you don't drink, you die. Much of
the collective learning, invention, shifts in social structure, have been geared toward
coping with the problem of energy flows as the population continued to expand by leaps
and bounds, from a tiny 10,000 people 74,000 years ago to over 7 billion people today.
So the beautiful thing about being able to remember and accumulate the ideas of your
ancestors is that some of their ideas are great for agriculture, also other things,
but mostly food. Whether it's new forms of irrigation invented in ancient Mesopotamia
or the four-crop rotation that gradually proliferated across Europe in the 17th and 18th centuries,
these innovations increased the number of potential innovators who could exist in a
social order without starving.
And there were also great innovative leaps in connectivity. For instance, the invention
of writing in ancient states about 5,000 years ago. Like, starting from a bureaucratic form
of accounting, mostly to count livestock, to an art, largely enjoyed by the elite, writing
gradually communicated more abstract and complex ideas. And those ideas became available to
more and more people as more people could read, until eventually writing became so popular
that these days, everyone writes books, even some of your Crash Course Big History hosts.
We also liked writing because it made it less likely that things we'd learned would be forgotten,
like when people started to write down what they knew, that knowledge became set in stone.
Sometimes literally! And then with the invention of printing in China and later Korea and the
printing press in Europe, more writing could be produced and circulated more quickly, and
often more cheaply than books copied out by hand. All of this turned into a beneficial
feedback cycle, potential innovators raise the carrying capacity of the population, more
people go on to produce more ideas, which raises the carrying capacity of the population,
which in turn produces more potential innovators. And we can do it all without anything bad
happening to the environment. What's that? Oh. Oh my.
So, throughout the agrarian period, collective learning continued to raise the carrying capacity
of the world. Populations grew from 6 million 10,000 years ago to 50 million by the dawn
of states to 120 million by 1000 BCE in the midst of classical civilizations. By the end
of the agrarian era, in the beginning of the industrial revolution, 954 million people lived on the Earth.
But while collective learning gradually raised the carrying capacity in the agrarian era,
it did not keep pace with population growth, and this is a significant problem with humanity.
Just like any other animals in nature, we breed until we strain the resources of our
environment, so we are prone toward unsustainable levels of overpopulation. So every two or
three centuries, humans would hit the carrying capacity and then the population would recoil,
resulting in famine, disease, periods of in-fighting and population decline, in every agrarian
civilization, from civil wars between Caesar and Pompey, the English War of the Roses,
to the revolt of the Janissaries in the Ottoman Empire, and similar events all across the
world, the cycles of prosperity, strain, crisis, and civil in-fighting repeated themselves.
And I do worry a little bit that when we talk about traditional history, we don't do it
enough in the context of carrying capacity. We are, after all, organisms, and we behave
a lot like other animals on this planet. We want there to be more of us, and we want more
resources for that more of us to enjoy.
So that broad, Big History take on the agrarian era takes us to the Age of Exploration. Explorers,
including Christopher Columbus, but also many others, united the previously isolated world
zones of Afro-Eurasia, the Americas, Australasia, and the Pacific. Eventually, this combination
of world zones into one unified global network, although not that unified, would produce an
even more astounding rise in complexity: the Modern Revolution -- we'll talk about that next time.