Lecture Tim Dyson,iss,The Hague,The Netherlands,23 April 2009 part 3.mov — Transcript

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1. 0:00looking at in the stylized diagram now
2. 0:02I'm not able to get data for before 1840
3. 0:05I suspect that it exists and were we to
4. 0:08do that then we would find uh the birth
5. 0:10and the death rate being closer to each
6. 0:12other as we go further back in
7. 0:16time okay next one so the next slide has
8. 0:20four more examples of the
9. 0:24transition uh we've got two more
10. 0:27European examples uh England and Wales
11. 0:30uh in the uh over here um going a little
12. 0:35bit outside of Northwestern Europe we've
13. 0:37got Spain over here uh and then I have
14. 0:41very difficult to find these sorts of
15. 0:43data over long periods of time for
16. 0:46populations outside of Europe but we've
17. 0:49got two examples here um Taiwan the
18. 0:52transition I would say not quite
19. 0:54complete but more or less complete and
20. 0:57over here we have Egypt so these two
21. 1:01transitions sort of represent the
22. 1:04developing Transitions and these two are
23. 1:07obviously two more historical
24. 1:10examples now
25. 1:12importantly and for several reasons that
26. 1:15I'm not going to be able to talk about
27. 1:16now more recent transitions in
28. 1:19developing countries have involved much
29. 1:22faster rates of population growth than
30. 1:25applied in the historical transitions of
31. 1:28Europe so if we if we look at data for
32. 1:31the
33. 1:32Netherlands Spain and even England the
34. 1:35population growth rate rarely exceeded
35. 1:391.5% per year and then only
36. 1:42briefly in the case of France I think
37. 1:45I'm writing saying that the population
38. 1:47growth rate never approached 1% per year
39. 1:50I think the peak was about 0.7% per year
40. 1:54looking at things on a
41. 1:57uh annual basis
42. 2:01however more recent Transitions and you
43. 2:03can actually see this if you look at the
44. 2:06examples for Taiwan and Egypt although
45. 2:09uh other populations would show this
46. 2:12even more were the data to exist more
47. 2:14recent transitions have involved annual
48. 2:17growth rates of
49. 2:182.5% per year or more frequently lasting
50. 2:22over many
51. 2:23decades indeed in some World regions
52. 2:27particularly subsaharan Africa but not
53. 2:29just subsaharan Africa national
54. 2:32population growth rates of 3% per year
55. 2:35have been
56. 2:36common in this context United Nations uh
57. 2:40estimates suggest that the populations
58. 2:42of West Asia that's taking the total
59. 2:45population of West Asia together on the
60. 2:47one hand and also subsaharan Africa they
61. 2:51both grew at about 2.5% per year between
62. 2:541950 and the year 2010 so that's a
63. 2:5860-year period at 2.5 5% per year and
64. 3:02the population doubling time associated
65. 3:04with a growth rate of 2.5% is 28 years
66. 3:09so these are rapid rates of growth for
67. 3:11extended periods of
68. 3:13time next one good
69. 3:17on now this this plot here shows you if
70. 3:22you look at the main line the Top
71. 3:24Line the size of the world's population
72. 3:27uh essentially from the year zero up up
73. 3:29until uh the present
74. 3:33day and what I want to emphasize is that
75. 3:37when you look at this sort of graph as
76. 3:39you often do what you're looking at is
77. 3:42the outcome of the demographic
78. 3:43transition except here at the global
79. 3:45level at the World level so people often
80. 3:48look at this and they think oh the
81. 3:50population's gone up but you've got to
82. 3:51understand why the population's
83. 3:53increased that is the growth that is
84. 3:55consequent upon what I will refer to as
85. 3:58the global demographic uh trans
86. 4:01transition so it is the demographic
87. 4:04transition that explains the
88. 4:05unprecedented growth in the size of the
89. 4:08human population since about 1750 and
90. 4:11even on that crude graph you can see
91. 4:13that it picks up at about
92. 4:161750 at the global level at the World
93. 4:19level taking the human population as a
94. 4:21whole the transition will probably lead
95. 4:24to roughly a ninefold increase in the
96. 4:28size of the human population between
97. 4:301750 and the year 2050 although it will
98. 4:34probably come to an end a few decades
99. 4:36after 2050 so roughly a growth multiple
100. 4:40of nine for the human population as a
101. 4:43whole associated with the demographic
102. 4:46transition now I have to say this
103. 4:51here most of this
104. 4:53growth has happened in my
105. 4:55lifetime honor it's so very serious
106. 4:58point most of that growth has happened
107. 5:01in my
108. 5:02lifetime so when I was born and I'm not
109. 5:05that
110. 5:06old when I was born the total population
111. 5:10of the world was slightly less than 2.5
112. 5:13billion it's now 6.7 billion and of
113. 5:17course it's still increasing I say this
114. 5:20partly because I'm amazed at this
115. 5:23myself a short life a short life
116. 5:25hopefully a bit longer but a huge
117. 5:29demographic increase huge proportion of
118. 5:32that has occurred in my lifetime and if
119. 5:35that population growth is going to have
120. 5:39effects and it does have all sorts of
121. 5:40effects I expect those effects to be
122. 5:43lagged because lags are involved in the
123. 5:46whole of the story that I'm talking to
124. 5:47you about today even though I can't go
125. 5:49into those lags but there are lags
126. 5:52always
127. 5:54involved okay now it should be clear to
128. 5:57you already that the PO population
129. 6:00growth multiples resulting from the
130. 6:02transition vary greatly between
131. 6:05different parts of the world different
132. 6:08populations so for the world as a whole
133. 6:10it's going to be roughly
134. 6:12nine in Europe looking at the European
135. 6:15transitions which are now over
136. 6:17populations generally increase by
137. 6:19factors of say two or
138. 6:23three in China the population growth
139. 6:27multiple will probably be in the
140. 6:29vicinity of three or four comparing the
141. 6:33size of the population at the start of
142. 6:34the transition and the end of China's
143. 6:38transition and in India the population
144. 6:41growth multiple will probably something
145. 6:43be like five or
146. 6:45six in transitions elsewhere however
147. 6:48looking at the rest of the world growth
148. 6:51multiples will
149. 6:53vary between five well five and upwards
150. 6:57five five to 20
151. 7:00if you just take for example the United
152. 7:02Nations estimates um these suggest that
153. 7:05even if we only consider the period
154. 7:08between 1950 and 2050 the population of
155. 7:13East Africa will grow by a growth
156. 7:14multiple of 11 although the population
157. 7:17of East Africa was growing before 1950
158. 7:20and it will be growing Beyond 2050 for
159. 7:24sure now in my
160. 7:27view rapid demographic change is
161. 7:31problematic irrespective of its
162. 7:34direction irrespective of whether it's
163. 7:36up or down so first
164. 7:43slide a look at I've picked here Russia
165. 7:46and
166. 7:48Nigeria suggests some of the reasons
167. 7:51why and it also highlights the important
168. 7:54role of age structure the age structure
169. 7:57of the population
170. 7:59particularly in the context of
171. 8:01demographic momentum and demographic
172. 8:04momentum can work in both directions
173. 8:06whether a population is growing or
174. 8:07whether it's
175. 8:09declining now importantly the graphs
176. 8:13we're going to look at now don't plot
177. 8:16percentage age distributions they plot
178. 8:19absolute
179. 8:21numbers okay so the next
180. 8:24slide right that's what happened to the
181. 8:27population of Russia on the left hand
182. 8:29side and Nigeria on the right hand side
183. 8:33During the period between
184. 8:351950 and
185. 8:382000 these are un uh uh
186. 8:42figures in Broad
187. 8:44terms Russia was in the final stages of
188. 8:47the demographic transition between 1950
189. 8:50and
190. 8:512000 and its population increased from
191. 8:54about 103 million to about 147 million
192. 8:59over the