1
00:00:06,988 --> 00:00:09,446
Today ,more than half of all people in the world

2
00:00:09,446 --> 00:00:11,366
live in an urban area.

3
00:00:11,366 --> 00:00:14,694
By mid-century, this will increase to 70%.

4
00:00:14,694 --> 00:00:16,782
But as recently as 100 years ago,

5
00:00:16,782 --> 00:00:19,491
only two out of ten people lived in a city,

6
00:00:19,491 --> 00:00:21,615
and before that, it was even less.

7
00:00:21,615 --> 00:00:22,700
How have we reached

8
00:00:22,700 --> 00:00:24,785
such a high degree of urbanization,

9
00:00:24,785 --> 00:00:27,180
and what does it mean for our future?

10
00:00:27,180 --> 00:00:29,250
In the earliest days of human history,

11
00:00:29,250 --> 00:00:31,000
humans were hunter-gatherers,

12
00:00:31,000 --> 00:00:32,709
often moving from place to place

13
00:00:32,709 --> 00:00:34,645
in search of food.

14
00:00:35,153 --> 00:00:36,744
But about 10,000 years ago,

15
00:00:36,744 --> 00:00:38,831
our ancestors began to learn the secrets

16
00:00:38,831 --> 00:00:40,204
of selective breeding

17
00:00:40,204 --> 00:00:42,612
and early agricultural techniques.

18
00:00:42,612 --> 00:00:43,881
For the first time,

19
00:00:43,881 --> 00:00:45,113
people could raise food

20
00:00:45,113 --> 00:00:46,555
rather than search for it,

21
00:00:46,555 --> 00:00:47,938
and this led to the development

22
00:00:47,938 --> 00:00:49,521
of semi-permanent villages

23
00:00:49,521 --> 00:00:51,775
for the first time in history.

24
00:00:51,775 --> 00:00:54,271
"Why only semi-permanent?" you might ask.

25
00:00:54,271 --> 00:00:57,036
Well, at first, the villages still had to relocate

26
00:00:57,036 --> 00:00:58,460
every few years

27
00:00:58,460 --> 00:01:00,441
as the soil became depleted.

28
00:01:00,441 --> 00:01:02,329
It was only with the advent of techniques

29
00:01:02,329 --> 00:01:04,502
like irrigation and soil tilling

30
00:01:04,502 --> 00:01:06,044
about 5,000 years ago

31
00:01:06,044 --> 00:01:07,664
that people could rely on a steady

32
00:01:07,664 --> 00:01:09,501
and long-term supply of food,

33
00:01:09,501 --> 00:01:11,913
making permanent settlements possible.

34
00:01:11,913 --> 00:01:13,434
And with the food surpluses

35
00:01:13,434 --> 00:01:15,056
that these techniques produced,

36
00:01:15,056 --> 00:01:17,595
it was no longer necessary for everyone to farm.

37
00:01:17,595 --> 00:01:18,992
This allowed the development

38
00:01:18,992 --> 00:01:20,680
of other specialized trades,

39
00:01:20,680 --> 00:01:22,906
and, by extension, cities.

40
00:01:23,567 --> 00:01:25,986
With cities now producing surplus food,

41
00:01:25,986 --> 00:01:26,974
as well as tools,

42
00:01:26,974 --> 00:01:27,438
crafts,

43
00:01:27,438 --> 00:01:28,572
and other goods,

44
00:01:28,572 --> 00:01:30,509
there was now the possibility of commerce

45
00:01:30,509 --> 00:01:33,405
and interaction over longer distances.

46
00:01:33,405 --> 00:01:34,742
And as trade flourished,

47
00:01:34,742 --> 00:01:37,549
so did technologies that facilitated it,

48
00:01:37,549 --> 00:01:39,467
like carts,

49
00:01:39,467 --> 00:01:40,901
ships,

50
00:01:40,901 --> 00:01:41,962
roads,

51
00:01:41,962 --> 00:01:43,154
and ports.

52
00:01:43,154 --> 00:01:45,320
Of course, these things required even more labor

53
00:01:45,320 --> 00:01:46,789
to build and maintain,

54
00:01:46,789 --> 00:01:47,987
so more people were drawn

55
00:01:47,987 --> 00:01:49,794
from the countryside to the cities

56
00:01:49,794 --> 00:01:51,247
as more jobs and opportunities

57
00:01:51,247 --> 00:01:52,960
became available.

58
00:01:52,960 --> 00:01:55,141
If you think modern cities are overcrowded,

59
00:01:55,141 --> 00:01:56,461
you may be surprised to learn

60
00:01:56,461 --> 00:01:59,906
that some cities in 2000 B.C. had population densities

61
00:01:59,906 --> 00:02:03,909
nearly twice as high as that of Shanghai or Calcutta.

62
00:02:03,909 --> 00:02:04,902
One reason for this

63
00:02:04,902 --> 00:02:07,524
was that transportation was not widely available,

64
00:02:07,524 --> 00:02:10,150
so everything had to be within walking distance,

65
00:02:10,150 --> 00:02:12,156
including the few sources of clean water

66
00:02:12,156 --> 00:02:13,774
that existed then.

67
00:02:13,774 --> 00:02:15,407
And the land area of the city

68
00:02:15,407 --> 00:02:17,648
was further restricted by the need for walls

69
00:02:17,648 --> 00:02:20,116
to defend against attacks.

70
00:02:20,116 --> 00:02:22,990
The Roman Empire was able to develop infrastructure

71
00:02:22,990 --> 00:02:25,043
to overcome these limitations,

72
00:02:25,043 --> 00:02:26,327
but other than that,

73
00:02:26,327 --> 00:02:27,628
modern cities as we know them,

74
00:02:27,628 --> 00:02:28,943
didn't really get their start

75
00:02:28,943 --> 00:02:30,940
until the Industrial Revolution,

76
00:02:30,940 --> 00:02:33,697
when new technology deployed on a mass scale

77
00:02:33,697 --> 00:02:36,386
allowed cities to expand and integrate further,

78
00:02:36,386 --> 00:02:37,672
establishing police,

79
00:02:37,672 --> 00:02:38,271
fire,

80
00:02:38,271 --> 00:02:39,782
and sanitation departments,

81
00:02:39,782 --> 00:02:41,342
as well as road networks,

82
00:02:41,342 --> 00:02:43,815
and later electricity distribution.

83
00:02:43,815 --> 00:02:46,572
So, what is the future of cities?

84
00:02:46,572 --> 00:02:49,475
Global population is currently more than 7 billion

85
00:02:49,475 --> 00:02:52,227
and is predicted to top out around 10 billion.

86
00:02:52,227 --> 00:02:53,730
Most of this growth will occur

87
00:02:53,730 --> 00:02:57,023
in the urban areas of the world's poorest countries.

88
00:02:57,023 --> 00:02:58,943
So, how will cities need to change

89
00:02:58,943 --> 00:03:01,134
to accommodate this growth?

90
00:03:01,134 --> 00:03:03,309
First, the world will need to seek ways

91
00:03:03,309 --> 00:03:04,754
to provide adequate food,

92
00:03:04,754 --> 00:03:05,714
sanitation,

93
00:03:05,714 --> 00:03:07,954
and education for all people.

94
00:03:07,954 --> 00:03:09,831
Second, growth will need to happen

95
00:03:09,831 --> 00:03:11,713
in a way that does not damage the land

96
00:03:11,713 --> 00:03:13,796
that provides us with the goods and services

97
00:03:13,796 --> 00:03:16,513
that support the human population.

98
00:03:17,159 --> 00:03:18,590
Food production might move

99
00:03:18,590 --> 00:03:20,713
to vertical farms and skyscrapers,

100
00:03:20,713 --> 00:03:21,795
rooftop gardens,

101
00:03:21,795 --> 00:03:24,272
or vacant lots in city centers,

102
00:03:24,272 --> 00:03:25,802
while power will increasingly come

103
00:03:25,802 --> 00:03:28,689
from multiple sources of renewable energy.

104
00:03:28,689 --> 00:03:30,728
Instead of single-family homes,

105
00:03:30,728 --> 00:03:33,338
more residences will be built vertically.

106
00:03:33,338 --> 00:03:35,299
We may see buildings that contain everything

107
00:03:35,299 --> 00:03:37,616
that people need for their daily life,

108
00:03:37,616 --> 00:03:39,579
as well as a smaller, self-sufficient cities

109
00:03:39,579 --> 00:03:42,701
focused on local and sustainable production.

110
00:03:42,701 --> 00:03:44,794
The future of cities is diverse,

111
00:03:44,794 --> 00:03:45,466
malleable,

112
00:03:45,466 --> 00:03:46,328
and creative,

113
00:03:46,328 --> 00:03:48,593
no longer built around a single industry,

114
00:03:48,593 --> 00:03:50,968
but reflecting an increasingly connected

115
00:03:50,968 --> 00:03:53,087
and global world.