NARRATOR:
The last Ice Age
ended a little
over 10,000 years ago.
At that point,
human communities in
different parts of the world
began using a range
of new technologies
to increase the
energy and resources
they could extract
from their environments.
We call these new technologies
agriculture,
and its development is
our seventh threshold.
What ingredients
led to this threshold?
Well, first, thanks
to collective learning,
humans had accumulated
vast knowledge
about their environments
over many generations.
Second, by the end
of the last Ice Age,
humans had also settled
all parts of the world.
And some began to live
in denser communities.
Populations increased
and some regions
such as Mesopotamia
began to have
about as many people
as foraging techniques
could support.
Now, more people meant
you had to try to get
more food from a given area.
So some groups started using
simple forms of irrigation,
or they planted wheat,
or they herded goats
and cattle for their meat.
These experiments were the
beginning of agriculture.
Global climates also got warmer
and more stable
than ever before.
These conditions
made it possible to plant
and tend crops
with some confidence
that they would yield
abundant harvests.
Within a few generations, some
plants and even some animals
became domesticated,
or more dependent on humans.
And as animals became tastier
or more nutritious
or more docile,
they became more
attractive to farmers.
Farming took off and began
to spread around the world.
Agriculture was really
a way to increase the
amount of the sun's energy
that was used
by our own species.
So humans began
changing the plants,
the animals and the
landscapes around them
so that they could
use more and more
of the products
of photosynthesis.
This energy bonanza led
to the creation of villages,
of cities and of huge
agrarian civilizations.
Eventually, an even
bigger energy bonanza
would steer human history
towards threshold number eight,
the modern revolution.
