1
00:00:00,000 --> 00:00:11,099
Today, more than half of all people in the world live in an urban area.

2
00:00:11,099 --> 00:00:15,099
By mid-century, this will increase to 70%.

3
00:00:15,099 --> 00:00:17,100
But as recently as 100 years ago,

4
00:00:17,100 --> 00:00:19,100
only 2 out of 10 people lived in a city,

5
00:00:19,100 --> 00:00:22,100
and before that it was even less.

6
00:00:22,100 --> 00:00:25,100
How have we reached such a high degree of urbanization,

7
00:00:25,100 --> 00:00:27,100
and what does it mean for our future?

8
00:00:27,100 --> 00:00:29,100
In the earliest days of human history,

9
00:00:29,100 --> 00:00:31,100
humans were hunter-gatherers,

10
00:00:31,399 --> 00:00:33,820
often moving from place to place in search of food.

11
00:00:34,920 --> 00:00:36,859
But about 10,000 years ago,

12
00:00:37,020 --> 00:00:40,079
our ancestors began to learn the secrets of selective breeding

13
00:00:40,079 --> 00:00:42,119
and early agricultural techniques.

14
00:00:42,939 --> 00:00:46,640
For the first time, people could raise food rather than search for it,

15
00:00:46,640 --> 00:00:49,600
and this led to the development of semi-permanent villages

16
00:00:49,600 --> 00:00:51,200
for the first time in history.

17
00:00:52,320 --> 00:00:54,200
Why only semi-permanent, you might ask?

18
00:00:54,600 --> 00:00:58,000
Well, at first the villages still had to relocate every few years

19
00:00:58,000 --> 00:00:59,460
as the soil became depleted.

20
00:01:00,259 --> 00:01:04,439
It was only with the advent of techniques like irrigation and soil tilling

21
00:01:04,439 --> 00:01:09,420
about 5,000 years ago that people could rely on a steady and long-term supply of food,

22
00:01:09,799 --> 00:01:11,480
making permanent settlements possible.

23
00:01:12,260 --> 00:01:14,900
And with the food surpluses that these techniques produced,

24
00:01:15,200 --> 00:01:17,599
it was no longer necessary for everyone to farm.

25
00:01:18,099 --> 00:01:20,680
This allowed the development of other specialized trades,

26
00:01:20,879 --> 00:01:22,260
and by extension, cities.

27
00:01:23,299 --> 00:01:28,359
With cities now producing surplus food as well as tools, crafts, and other goods,

28
00:01:28,359 --> 00:01:32,799
there was now the possibility of commerce and interaction over longer distances.

29
00:01:33,799 --> 00:01:37,260
And as trade flourished, so did technologies that facilitated it,

30
00:01:37,799 --> 00:01:42,620
like carts, ships, roads, and ports.

31
00:01:43,239 --> 00:01:46,680
Of course, these things required even more labor to build and maintain,

32
00:01:47,000 --> 00:01:49,819
so more people were drawn from the countryside to the cities

33
00:01:49,819 --> 00:01:52,480
as more jobs and opportunities became available.

34
00:01:52,900 --> 00:01:55,120
If you think modern cities are overcrowded,

35
00:01:55,420 --> 00:01:58,540
you may be surprised to learn that some cities in 2000 BC

36
00:01:58,540 --> 00:02:03,079
had population densities nearly twice as high as that of Shanghai or Calcutta.

37
00:02:04,040 --> 00:02:07,379
One reason for this was that transportation was not widely available,

38
00:02:07,900 --> 00:02:10,120
so everything had to be within walking distance,

39
00:02:10,539 --> 00:02:13,379
including the few sources of clean water that existed then.

40
00:02:13,699 --> 00:02:16,539
And the land area of the city was further restricted

41
00:02:16,539 --> 00:02:19,180
by the need for walls to defend against attacks.

42
00:02:20,020 --> 00:02:24,699
The Roman Empire was able to develop infrastructure to overcome these limitations.

43
00:02:25,120 --> 00:02:27,759
But other than that, modern cities as we know them

44
00:02:27,759 --> 00:02:30,620
didn't really get their start until the Industrial Revolution,

45
00:02:31,120 --> 00:02:33,699
when new technology deployed on a mass scale

46
00:02:33,699 --> 00:02:36,419
allowed cities to expand and integrate further,

47
00:02:36,860 --> 00:02:39,819
establishing police, fire, and sanitation departments,

48
00:02:39,819 --> 00:02:43,139
as well as road networks and later electricity distribution.

49
00:02:44,360 --> 00:02:46,080
So what is the future of cities?

50
00:02:46,800 --> 00:02:49,439
Global population is currently more than 7 billion

51
00:02:49,439 --> 00:02:51,900
and is predicted to top out around 10 billion.

52
00:02:52,680 --> 00:02:56,680
Most of this growth will occur in the urban areas of the world's poorest countries.

53
00:02:57,400 --> 00:03:00,539
So, how will cities need to change to accommodate this growth?

54
00:03:01,280 --> 00:03:07,560
First, the world will need to seek ways to provide adequate food, sanitation, and education for all people.

55
00:03:08,099 --> 00:03:15,800
Second, growth will need to happen in a way that does not damage the land that provides us with the goods and services that support the human population.

56
00:03:15,800 --> 00:03:23,900
Food production might move to vertical farms and skyscrapers, rooftop gardens, or vacant lots in city centers,

57
00:03:24,319 --> 00:03:28,240
while power will increasingly come from multiple sources of renewable energy.

58
00:03:29,219 --> 00:03:32,800
Instead of single-family homes, more residences will be built vertically.

59
00:03:33,539 --> 00:03:37,319
We may see buildings that contain everything that people need for their daily life,

60
00:03:37,319 --> 00:03:42,099
as well as smaller, self-sufficient cities focused on local and sustainable production.

61
00:03:42,900 --> 00:03:46,099
The future of cities is diverse, malleable, and creative,

62
00:03:46,620 --> 00:03:48,620
no longer built around a single industry,

63
00:03:49,020 --> 00:03:52,180
but reflecting an increasingly connected and global world.