A Study of Population-Environment Dynamics

A STUDY OF POPULATIONENVIRONMENT DYNAMICS Shuhei Aida

and

Fumio Hasegawa *

Un£vers£ty of Electro·Commun£catzons,Cho!u·shz", Tokyo 182, Japan * Sh£mz'zu Construct£on Co., Ltd. Chuo·ku, Tokyo 104,Japan

ABSTRACT

initiate d. Let the name the Population Environment Dynamics denote to this study and present the results of basic studies here . The Population- Environment Dynamics is divided into four phases shown in Feg . 1.

Systems eng ineering deals with a large comp l e x system, "problematique", which do not lie in any sing l e branch of sc i ence or t echnol ogy but involve an interdisciplinary f i eld. The PopulationEnvironment Dynamics combines a technology and polit ica l science to build a model of Japanese population system. The socia l prob l e ms occasioned by the rapid changes in s tructure of population and environment relations over the pas t seve ral years have catapuled the population issue into a prominent pos ition in all regiona l planning processes. with the new found realization of the importance of Population-Environment Dynamics in virtually every aspect of an industrialized socie ty came a recognition of an almost total lack of kl1O\" l edge concerning the complex interr elationsh i ps involved. The relation between population and env ironment forming feedback loop structure , the r efo r e , th e PopulationEnvironment Dynamics have been emp loyed to analyze a variety of popu lation related problems for environment.

BASIC LAWS In the fie ld of phys ics, the laws of motion, which has become fundamental for the whole modern sc i ence , was first introduced by I saac Newton. The Newtonian law s of motion consi s t of three laws and every dynamics phenomenon can be expl ained by these laws . The Popu l ation -Environment Dyn a mics can be exam in ed both as physical phenomena and as soc ial p henomena. With respect to the former, three laws identical to Newton ' s can be substituted and guided to constitute basic laws for every phenomenon.

The First Law -

'Rice - grain Theory"

This is so-called the principle of inertia l aw. Suppose there is a heaped - up rice in a bowl. Trying to add one mor e bowl - ful of rice t o the bowl will be clear l y impo ss ibl e. However, even if the bowl seemed absolutely full, a grain of rice is s ure to be added on account of its st i ck iness. In spite of the nearing limit, more and more grain can be added in this manner and such g r ains amount to be q uite an increase. Thi s is the rice-grain the ory. Similar phenomenon occurs in the population expansion .

INTRonUCTION The prob l e m of popula tion should no long er be dealt mere l y as a demographic study. In ecology , which r egard s mankind as a compo s ·· ing factor of the nature , population is thought to be regulated by environment. Thomas Malthus' essay may have been written with the present excessive population growth in perspective , alread y in th e nineteenth century. Today, the Club of Rome forewarns the predicaments , man should look on to. This is a ll because man i s so e ndowed with the extraordinary intel ligence and rationality. Around man, there exist not only the natural environment but also the social, economi c , cu ltur al, artistic and various other environments . 11an inspir es these synthetic environments and the environments inspire man accordingly. Such repetition had been the cause of progress in man. Therefore, based on the concept of c lose interrelationship between population and environment, a series of s tudi es were

The Second Law The acceleration of a bod y is direct l y proportional to the resultant e xterna l force acting on the body and inversely propor tional to the mass of the body. Let the mass of the body be m and acceleration ~, where F = mU(. If m and ut are applied to the population scale and the growth ra t e , meaning the death rate deducted from the birth ra t e , respectively; the popu l ation scale v ari es on F . The larger the present sca l e o r the larger the growth rate, the greater the popu l ation scale. If the death rate

509

S. Aida and F. Hase gm.,ra

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Physical ph ase

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third

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social psychology behavioral science

Social phase

economics sociology antholopology

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System simulation

1. Population-Environment Dynamics

exceed the birth rate , will be nagative as a mat t e r of course . I n short , the population acts on the prese nt populat i on scale as an operative for ce .

The Third Law Thi s law is sometimes called t he law of action and r eac ti on . The notion t hat the population affect the env ir o nme nt as the environment affect the pop ul a tion i s an impo rtant t heme s tud i ed in eco logy. The prese nc e o f equi librium between the popul ation and the envi r o nme nt i s so l e l y due t o t he homeosta ti s . As a count e rpart of the action, homeo sta ti c mechanism r eac t s t o The thr ee l aws stated k e e p stabi lit y. ab:lVe are extremel y importan t and essentia l in st ud ying the Population - Environment Dynamics.

BASIC CONCEPTS OF THE PROBLEM Th e resea r ch of the popu lation problem is based on the following three compon e nt s .

(1) Population size and growth rate (2) Age str ucture (3) The popU lation and relative spac ing of L1dividudls This resear c fl is developed mainl y on the third component . To clarify the problem of the third componen t, ' Brain stor ming' was held whose members consi s t of the you ng research workers such a s urban planners, economi s t s . socio l ogists, system eng ineers . and psycho logi st . Whil e there is a tendency that t 11e populat i on concentrates in the big cities, there is also a tend ency of going back to one ' s o wn home - countr y , b eing noted

as J,U -t urn phenomenon. Hereunde r are the logi ca l str uctur e and the results of this trend shown in Fig. 2. According to th e recent inves tiga tion cond u cted by the National Land Age n cy , the increasing population of Japan is est imated 1 5 , 000 , 000 by t he yea r of 1 985 . How can t his in creas ing quantity be distributed is a ser i ous p robl e m. Carr ying o n the research further, ' Brain storming ' cont inu ed and ob tained foll owing results.

1 ) Though there is a limit t o c ity facilities , the pop ulation is bound to increase to some exten t, O',-} '-l!:; to the first law ( rice - grain theory) of t he Popula tion-Environment Dynamics . 2) Attraction to city fa ci l i ti es wil l l e ad to stimulate the sprawl phenome " non. 3 ) Psychological l y, overpopu l ated society embod i es the danger of induc ing cr ime and of increas ing drug addicts out of alienation and isolation. 4) The social i ssu es s u ch as air po llution, c lamorousness , and b locking of day lights by buildings will be en l arged. 5) The persistent high price will put even more s train o n economy . 6) The function of ci ties will change from the energy-ori en t e d space to the spa ce th at produces, disposes and transmits information. Its result will emerge a s ' don ut- shaped ' phenome no n. Among the diversity of opinions presented,

511

Population- Environme nt Dynamics

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the above mentioned are d irect l y rela t ed t o thi s study . The ultimate cause of the p r ob l e m lies in the increase in popu lation . If it i s impossible to distribute t he increa sing populati on in cities , they must be dispersed in p rovin c i a l areas . To rea l ize it unde r the economic durability, indu s try mu st also b e dispersed.

DISPERSION OF INDUSTRY TO PROVINCIAL AREAS AND POPULA TI ON MIGRATION To make t he r e lat ionsh i p be t ween the di s persion of indus try t o prov in c i a l are a s and population migration c l ea r, the p r ob l em was focused on four basic items ,

structure

of

urban

ph e nomena

(1) The relation between industrial struc ture a nd popula tion In indus tr y l ocation theo r y , popula ti on has been considered in t erms of labou r population. Going through t he p r ocess of transition from the primary industry t o t he secondary industry, the intensive l abou r p attern sh i f t s to t he intens ive intellect pat t ern ,d e man d in g t he q uality of capab l e men ins t ead of th e quantity. The population structure is the g i ven condit i on t o t his probl e m, that is to s a y the age structu r e is invariab l e. Especially in Japan, the indus trial stru c tur e must be desiqned to be desirable cc:. r t:he ·Jen,.' r"lJl ,,-' -aged d':'f", il ~ a:1t. soc i e t y to w!tich ::;he i s in-

512

S. Aida and F. Hasegawa clined to be engaged in. This is because of the third law of the Population - Environment Dynamics.

conducted. In the district ca ll ed ' Setouch i' approximately 5/6 of the populati on of Chugoku and Shikoku districts i s concen trated, and developing as a n ew indust ri a l zone . The plan to disperse industry in Sh ikoku district associated with that of the popu la tion is being specu lated, however, th e ir relation has turned out to be a type of 'tr ade-off ' relation.

(2) The relation between soc ial phenomenon and population This problem is as diagramed in Fig 2. (3) The relation between natural en vironment and population

Ge n e rall y it is understood that the increase of industria l p roduct iv ity will affect the secondary ind ustry and the th irdly industry , widen the gross i ncome and annual revenue of the prefecture and t hereby enhance the living standard of its people. On the other hand, it may also mean the deterioration of envi ronmen t by air pol lution , water pollution and so forth. Besides the industrial organization ' s need to secure the new labour , Llnd , water and to provide a capital stock for in dust rial based society in order to ex ~ and the indu strial productivity , it wil l also be needing to obse r ve various e nviron ment regulations, r esu lti ng on the severity of the ex t e rn a l innovation sur r ound i ng the manufacturing industry . In this s tudy, five items, namely the number of ab l e emp l oyers , avai l able land measure , the available water s u pply, the provision of capital stock for th e r elevan t transportation soci e ty and the degree of permissible wate r pollution , are considered as impacts to control the in d us trial productivity.

Thi s problem i s s till under investigation. Within the condi tio n of limited food and energy , how shou l d man be supported is the prominent subject. Assuming food and energy as the C).t"c!rnal c orlditions , the siltlu la tion modE l as 1-_ 0 ho ..., l'opulati" " varies on its each level is now being developed . (4) Th e relation between urban environ ment and population Urban environment and population mig ration are closely related to social phenomena. This study i s centered on the question as to how the urban en vironment shou ld meet the g i ve n population struct ur e. This problem is also being Jeveloped. Among the four po in ts estab lished , the study on th e first po int is completed and i ts r es ult s are reported as follows . The interrelationship of these compon ents i s as stipulated in Fig. 3. Using this model , the project on popula tion in Shikoku district , wh ich is one of the major islands in Japan, adjacent to Chugoku dis tri ct , was

land

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CONCLUDING REMARKS An exampl e of the results is s ~own in Fig . 4. From t he char t, it is e vident that industrial productivity is controll e d by

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Population-Environment Dynamics

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the labour. Alt hough our age is gradua ll y turning toward the promotion of welfarepermeated society, it I-lill be quite difficu lt to pursue such state without an adequate degree of econom ic growth . Economy being sustained by the labour, the notion that there is limit to the quantitative economic growth, was obta in e d as our conclusion . REFERENCES (1) T. Mutoh, H. Sakai, e t aI , "An .tmalysis 110de l of the Developmentable Amount of Shipment of a Regional Manufacturing Industry" (Japan ese ) Japanese Series ,

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" System Dynamics", Ope rations Research Soc iety of Japan, 1977 (2) S . Aida, N. Honda and T. Furuta, "A Simulat ion Model of Regional Population for Japan", Proceedings of SCSC , 197 6 (3) S . Aida and N. Honda, "Environme ntal Index by Faces Method" , Proceedings of SCSC, 1975

(4) S. Aida and F. Hasegawa, " An Analysis of the Impact of Honshu-Shikoku Bridge" (Japanese), Joint Full Conference , Society of Instrument and Control Engineers, 197 6