NOT FOR QUOTATION WITHOUT PERMISSION OF THE AUTHOR
MIGRATION AND URBAN CHANGE
Piotr Korcelli October 1981 WP-81-140
Working Papers are interim reports on work of the International Institute for Applied Systems Analysis and have received only limited review. Views or opinions expressed herein do not necessarily repre- sent those of the Institute or of its National Member Organizations.
INTERNATIONAL INSTITUTE FOR APPLIED SYSTEMS ANALYSIS
A-2361 Laxenburg, Austria
FOREWORD
D e c l i n i n g r a t e s of n a t i o n a l p o p u l a t i o n growth, c o n t i n u i n g d i f f e r e n t i a l l e v e l s o f r e g i o n a l economic a c t i v i t y , and s h i f t s
i n t h e m i g r a t i o n p a t t e r n s of people and j o b s a r e c h a r a c t e r i s t i c e m p i r i c a l a s p e c t s of many developed c o u n t r i e s . I n some r e g i o n s t h e y have combined t o b r i n g a b o u t r e l a t i v e (and i n some c a s e s a b s o l u t e ) p o p u l a t i o n d e c l i n e of h i g h l y u r b a n i z e d a r e a s ; i n o t h e r s t h e y have b r o u g h t a b o u t r a p i d m e t r o p o l i t a n growth.
The o b j e c t i v e of t h e Urban Change Task i n I I A S A ' s Human
S e t t l e m e n t s and S e r v i c e s Area i s t o b r i n g t o g e t h e r and s y n t h e s i z e a v a i l a b l e e m p i r i c a l and t h e o r e t i c a l i n f o r m a t i o n on t h e p r i n c i p a l d e t e r m i n a n t s and consequences of such urban growth and d e c l i n e .
S p a t i a l p o p u l a t i o n p a t t e r n s and t r e n d s of 3 5 h i g h l y u r b a n i z e d r e g i o n s i n 1 2 member c o u n t r i e s o f I I A S A a r e s e t o u t i n t h i s p a p e r , u s i n g d a t a c o l l e c t e d f o r t h e M i g r a t i o n and S e t t l e m e n t Comparative Study. The f i n d i n g s a r e d i s c u s s e d w i t h i n t h e c o n t e x t of f i v e h y p o t h e s e s t h a t d e a l w i t h e x p e c t e d urban change under c o n d i t i o n s of low n a t u r a l i n c r e a s e and h i g h l e v e l s of u r b a n i z a t i o n , and t h e l i m i t a t i o n s of such a comparative s t u d y a r e i d e n t i f i e d .
A l i s t of r e c e n t p u b l i c a t i o n s i n t h e Urban Change S e r i e s a p p e a r s a t t h e end of t h i s p a p e r .
Andrei Rogers Chairman
Human S e t t l e m e n t s and S e r v i c e s Area
ABSTRACT
This paper examines the population development of large urban regions. It discusses several hypotheses pertaining to patterns of settlement change in highly urbanized countries.
Such hypotheses refer to interrelations between population
growth and urban size, the role of migration and natural increase as components of urban population change, the overall spatial mobility, the hierarchical migration, and the age distribution of migrants moving between, out of, and into large urban areas.
Empirical material used in the analysis is derived from IIASA's
Comparative Study on Migration and Settlement.
CONTENTS
INTRODUCTION 1
I . URBAN CHANGE: INTERPRETATIONS AND POLICY RESPONSES 3
11. REGIONAL AGGREGATION UNITS 9
111. F I V E HYPOTHESES CONCERNING PATTERNS OF URBAN CHANGE 2 5
CONCLUSION 6 5
REFERENCES 6 7
M I G R A T I O N AND URBAN CHANGE
INTRODUCTION
C o n c e n t r a t i o n w i t h i n t h e u r b a n h i e r a r c h y was a d o m i n a n t theme i n t h e l i t e r a t u r e o n s e t t l e m e n t c h a n g e d u r i n g t h e 1950s a n d 1 9 6 0 s . S p a t i a l c o n c e n t r a t i o n was e x p r e s s e d i n t e r m s o f t h e
i n c r e a s i n g s i z e - - b o t h a b s o l u t e and r e l a t i v e - - o f t h e l a r g e s t c i t i e s , t h e i r p h y s i c a l e x p a n s i o n ( d e v e l o p m e n t o f u r b a n agglom- e r a t i o n s o r m e t r o p o l i t a n a r e a s ) , and t h e g r a d u a l e l i m i n a t i o n o f l o w e r - l e v e l u n i t s w i t h i n t h e c e n t r a l - p l a c e s y s t e m s . P r e d i c t i o n s b a s e d o n t h e s e t r e n d s showed t h e b u l k o f t h e p o p u l a t i o n o f
t h e p r e s e n t - d a y u r b a n i z e d c o u n t r i e s t o b e c l u s t e r e d i n a few m e g a l o p o l i s e s a n d t h e a c t u a l d i s a p p e a r a n c e o f s m a l l - and medium- s i z e d towns by t h e e n d o f t h e c e n t u r y .
Around 1970 s e v e r a l a u t h o r s , n o t a b l y B e r r y ( 1 9 7 0 ) , and
Friedman a n d M i l l e r ( 1 9 6 5 ) , began t o c l a i m t h a t t h e s u b u r b a n i z a - t i o n o f p o p u l a t i o n and economic a c t i v i t y , o b s e r v e d i n many h i g h l y u r b a n i z e d c o u n t r i e s d u r i n g t h e p r e v i o u s d e c a d e s , c o u l d u l t i m a t e l y l e a d t o d i s p e r s a l a t a n i n t e r r e g i o n a l s c a l e . O t h e r s , however, w e r e s t i l l p r e d i c t i n g a c o n t i n u i n g c o n c e n t r a t i o n o f p o p u l a t i o n and employment i n t h e l a r g e s t m e t r o p o l i t a n a r e a s and a c o n t i n u i n g r e l a t i v e economic d e c l i n e o f most r u r a l and small-town a r e a s .
The l a t t e r n o t i o n s were d e e p l y r o o t e d i n t h e e x i s t i n g t h e o r y o f s e t t l e m e n t development; hence t h e e v i d e n c e o f c o n t r a c t i o n o f t h e p o p u l a t i o n of a number o f l a r g e m e t r o p o l i t a n a r e a s d u r i n g t h e e a r l y 1970s was somewhat e m p h a t i c a l l y l a b e l e d a s " a c l e a n b r e a k w i t h t h e p a s t " ( V i n i n g and S t r a u s s 1 9 7 7 ) .
On t h e o t h e r hand, t h e s u b s e q u e n t , more s y s t e m a t i c a n a l y s e s o f economic and demographic t r e n d s a s w e l l a s o f h i s t o r i c a l p a t - t e r n s o f u r b a n growth have l e d a number o f r e s e a r c h e r s t o t h e c o n c l u s i o n t h a t i n t e r r e g i o n a l p o p u l a t i o n d e c o n c e n t r a t i o n
r e p r e s e n t s a "normalt1 phenomenon, i n f a c t a s t a g e i n t h e u r b a n t r a n s i t i o n - - a s e c u l a r development c y c l e o f u r b a n i z e d a r e a s
( K l a a s s e n and P e a l i n c k 1979; Leven 1 9 7 8 a ) . S t i l l , i t h a s been g e n e r a l l y acknowledged t h a t t h e o r i e s o f u r b a n growth and s t r u c t u r e a r e y e t t o i n c o r p o r a t e t h e s e o b s e r v e d developments i n t h e i r
r e s p e c t i v e frameworks (see Hansen 1 9 7 6 ) .
I n a d e q u a c i e s of t h e a v a i l a b l e t h e o r y have a l s o been r e f l e c t e d i n t h e f i e l d o f u r b a n p o l i c i e s , which t r a d i t i o n a l l y , and a l m o s t u n i v e r s a l l y , a d o p t e d t h e g o a l s o f r e s t r i c t i n g t h e e x p a n s i o n o f l a r g e u r b a n a g g l o m e r a t i o n s w h i l e promoting t h e growth c e n t e r s w i t h i n e c o n o m i c a l l y l e s s a c t i v e and s p a r s e l y p o p u l a t e d r e g i o n s . Hence, a s H a l l and M e t c a l f (1978) p o i n t e d o u t , i n t h e c a s e of h i g h l y u r b a n i z e d c o u n t r i e s some of t h e s e p o l i c i e s w e r e a d d r e s s i n g t h e p a s t , r a t h e r t h a n p r e s e n t - d a y i s s u e s . A r e f o r m u l a t i o n o f p r e v a i l i n g u r b a n p o l i c i e s h a s t h e r e f o r e become a n i m p o r t a n t i s s u e i n a number o f c o u n t r i e s . A s mentioned e a r l i e r , however, t h i s t a s k h a s been f a c e d w i t h l i m i t a t i o n s o f u r b a n development t h e o r y , a s w e l l a s p i e c e m e a l e m p i r i c a l e v i d e n c e c o n c e r n i n g s e t t l e m e n t t r a n s f o r m a t i o n s d u r i n g t h e r e c e n t p a s t .
A g a i n s t t h i s background, S e c t i o n I o f t h i s p a p e r summarizes t h e r e c e n t d i s c u s s i o n c o n c e r n i n g e x p l a n a t o r y f a c t o r s and c o r r e - l a t e s of u r b a n c h a n g e , i n c l u d i n g p o l i c y a s p e c t s . The r e m a i n i n g s e c t i o n s a r e b a s e d on r e s u l t s o f t h e Comparative S t u d y on Migra- t i o n and S e t t l e m e n t c a r r i e d o u t a t IIASA between 1975-78. S p a t i a l p o p u l a t i o n p a t t e r n s and t r e n d s f o r 3 5 u r b a n i z e d r e g i o n s i n 12
European c o u n t r i e s and J a p a n a r e compared w i t h s e l e c t e d h y p o t h e s e s p e r t a i n i n g t o p a t t e r n s o f u r b a n change t h a t c o u l d b e e x p e c t e d
under c o n d i t i o n s o f slow o v e r a l l p o p u l a t i o n growth and h i g h l e v e l s o f u r b a n i z a t i o n . Some o f t h e l i m i t a t i o n s o f s u c h a c r o s s - s e c t i o n a l a p p r o a c h a r e n o t e d i n c o n c l u d i n g r e m a r k s .
I . URBAN CHANGE: INTERPRETATIONS AND POLICY RESPONSES
With t h e n o t a b l e e x c e p t i o n o f Mumford's (1961) c o n c e p t o f a c i t y l i f e - c y c l e a s w e l l a s o f t h e u r b a n t r a n s i t i o n c o n c e p t
( K l a a s s e n and P a e l i n c k 1979; van den Berg and K l a a s s e n 1 9 7 8 ) , t h e o r i e s of u r b a n development have t r a d i t i o n a l l y f o c u s e d on u r b a n economic and p o p u l a t i o n growth and on t h e t r a n s f o r m a t i o n o f s p a c e w i t h i n u r b a n i z e d a r e a s (see Hansen 1976, f o r a c r i t i c a l a p p r a i s a l ) . T h i s i s l a r g e l y why t h e phenomenon o f l a r g e - c i t y c o n t r a c t i o n , which a p p e a r e d i n t h e 1 9 7 0 s , h a s been a c c e p t e d w i t h some r e l u c t a n c e and s u r p r i s e .
I n t h e f i e l d o f u r b a n economics, t h e emphasis on s i z e a s a p o s i t i v e and s t r o n g c o r r e l a t e o f growth was c o n t a i n e d i n t h e e a r l y n o t i o n o f " u r b a n r a t c h e t " i n t r o d u c e d by F l o r e n c e and d e v e l o p e d by Thompson ( 1 9 6 5 ) . Once a c i t y r e a c h e s a l a r g e
p o p u l a t i o n s i z e ( u s u a l l y d e f i n e d a s 250,000-300,000 i n h a b i t a n t s ) , i t s f u r t h e r c o n t i n u i n g e x p a n s i o n was c l a i m e d t o b e a s s u r e d
b e c a u s e o f i t s a g g l o m e r a t i o n economies and d i v e r s i f i e d i n d u s t r i a l b a s e . Market t e s t s were showing i n c r e a s i n g economic e f f i c i e n c y g r a d i e n t s w i t h i n c r e a s i n g u r b a n s i z e , even beyond t h e popula- t i o n t h r e s h o l d s o f t h e l a r g e s t e x i s t i n g u r b a n c e n t e r s (Alonso 1971; Mera 1 9 7 3 ) . C o n c e p t s o f s p a t i a l d i f f u s i o n a t t a c h t o c i t i e s l o c a t e d a t upper l e v e l s o f t h e u r b a n h i e r a r c h y t h e r o l e o f o r i g i n s o f g r o w t h - i n d u c i n g i n n o v a t i o n s ( ~ a s u s n 1 9 7 3 ) . Adop- t i o n o f s u c h an a s s u m p t i o n , c o r r o b o r a t e d by t h e e m p i r i c a l e v i - d e n c e a v a i l a b l e i n t h e 1960s ( s e e R i c h a r d s o n 1973) l e d t o t h e f o r m u l a t i o n o f s e t t l e m e n t s y s t e m models i n which l a r g e c i t i e s e n j o y e d s u s t a i n e d growth b a s e d on t h e i r a d v a n t a g e s a s nodes f o r p r o d u c t i o n and o r g a n i z a t i o n a l l i n k a g e s and h e n c e , d e c i s i o n - making c e n t e r s ( P r e d 1 9 7 5 ) . On t h e o t h e r hand, u r b a n growth models were l e s s s u c c e s s f u l i n i n c o r p o r a t i n g l o c a t i o n a l f a c t o r s
t h a t r e p r e s e n t n e g a t i v e e x t e r n a l i t i e s ( f o r some new d e p a r t u r e s , s e e T h i s s e and P a p a g e o r g i o u 1 9 8 1 ) .
I n g e n e r a l , t h e f o r m a l t h e o r y o f urban growth h a s f a l l e n s h o r t o f p r o v i d i n g f u l l i n s i g h t s i n t o t h e t y p e of urban change e x p e r i e n c e d i n many u r b a n i z e d c o u n t r i e s d u r i n g t h e 1 9 7 0 s , o r i n t o t h e phenomenon l a b e l e d by R i c h a r d s o n (1979) a s s p a t i a l p o l a r i z a t i o n r e v e r s a l . Faced w i t h s u c h d i s c r e p a n c i e s , t h e p l a n n e r s and e m p i r i c a l l y o r i e n t e d r e s e a r c h e r s have a t t e m p t e d t o d e v e l o p b r o a d e r i n t e r p r e t i v e frameworks i n which o b s e r v e d u r b a n t r e n d s a r e a t t r i b u t e d t o s e t s o f exogenous f a c t o r s . A s shown i n T a b l e 1 , t h e r e i s a c e r t a i n c o n s e n s u s among t h e
v a r i o u s a u t h o r s i n t h e s e l e c t i o n o f b a s i c d e t e r m i n a n t s o f r e c e n t s e t t l e m e n t d e c o n c e n t r a t i o n t r e n d s . The t a b l e , which summarizes r a t h e r t h a n l i s t s i n f u l l t h e d e t e r m i n a n t s o f u r b a n c h a n g e ,
f o l l o w s t h e c o n v e n t i o n a l d i s a g g r e g a t i o n o f f i v e c a t e g o r i e s : economic, demographic, s o c i a l , r e s o u r c e - e n v i r o n m e n t a l , and p o l i c y - r e l a t e d d e t e r m i n a n t s .
W i t h i n t h e g r o u p o f economic f a c t o r s t h e e v o l v i n g r o l e o f s c a l e and a g g l o m e r a t i o n economies comes t o t h e f o r e g r o u n d . A s Leven (1978a) n o t e d , when s c a l e i s a p p r o a c h e d from t h e p o i n t o f view o f consumption r a t h e r t h a n p r o d u c t i o n , t h e s e t t l e m e n t
d e c o n c e n t r a t i o n may b e more e a s i l y i n t e r p r e t e d w i t h i n t h e frame- work o f economic l o c a t i o n t h e o r y . Even w i t h t h e r e f e r e n c e t o
s c a l e economies i n p r o d u c t i o n , however, modern o r g a n i z a t i o n a l s t r u c t u r e s f a v o r s m a l l e r o v e r l a r g e r u n i t s and h e n c e , p h y s i c a l d e c o n c e n t r a t i o n o f economic a c t i v i t i e s ( I l l e r i s 1 9 8 0 ) . The r e d u c t i o n i n t h e b u l k - t o - v a l u e r a t i o s f o r most commodities h a s had s i m i l a r e f f e c t s (Leven 1 9 7 8 b ) . T e c h n o l o g i c a l improvements, i n p a r t i c u l a r t h e advanced i n f o r m a t i o n - t r a n s m i s s i o n s y s t e m s , may have a l s o r e n d e r e d t h e s p a t i a l c l u s t e r i n g o f p r o d u c t i o n
e s t a b l i s h m e n t s and t h e need f o r f a c e - t o - f a c e c o n t a c t s l e s s
c r u c i a l . Macrae (1978) a r g u e s t h a t t h e need f o r o u t s i d e c o n t a c t s h a s been r e d u c e d by t h e i n t e r n a l i z a t i o n o f t e c h n i c a l s k i l l s
w i t h i n l a r g e c o r p o r a t i o n s , t h e t r e n d t h a t makes more e s t a b l i s h - ments f o o t l o o s e and c o r p o r a t i o n s h i g h l y m o b i l e . R i c h a r d s o n
(1978) g o e s a s t e p f u r t h e r by s u g g e s t i n g t h a t i f i n f o r m a t i o n l i n k a g e s a r e becoming r e l a t i v e l y more i m p o r t a n t t h a n p h y s i c a l
