Urban and ecosystem dynamics: past, present, future

Transcription

1 Uban and ecosystem dynamics: past, pesent, futue Douglas White Wokshop on aspects of Social and Socio-Envionmental Dynamics School of Human Evolution and Social Change and Cente fo Social Dynamics and Complexity

2 Thanks to Lauent Tambayong, UC Ivine Nataša Kejža, U Ljubljana Constantino Tsallis, Enesto Boges, Cento Basileio de Pesquisas Fısicas, Rio de Janeio Pete Tuchin, U Conn Céline Rozenblat, U Zuich Numeous ISCOM poject and membes, including Denise Pumain, Sande v.d. Leeuw, Luis Bettencout Commentatos Michael Batty, William Thompson, Geoge Modelski 2

3 Outline Measue fo city size deviations fom Zipfian constucted and fitted to thee Euasian wold egions. Does the shape paamete q of these distibutions oscillate histoically in longe peiods than expected at andom? Does fall in q away fom Zipfian coelate with othe measues of instability, e.g., intenecine wafae o sociopolitical violence? Do vaiations in shape paamete q epesent altenating peiods of stability and instability? Ae city distibutions histoically unstable, as agued by Michael Batty, Natue 2006, (citing White et al. 2005) Does shape paamete q fo China affect Euope q with a time lag (diffusion of innovation, Silk Route tade)? Do city size instabilities affect woldsystem centes? 3

4 Michael Batty (Natue, Dec 2006:592), using some of the same data as do we fo histoical cities (Chandle 987), states the case made hee: It is now clea that the evident maco-stability in such distibutions as uban ank-size hieachies at diffeent times can mask a volatile and often tubulent mico-dynamics, in which objects can change thei position o ank-ode apidly while thei aggegate distibution appeas quite stable. Futhe, Ou esults destoy any notion that ank-size scaling is univesal [they] show cities and civilizations ising and falling in size at many times and on many scales. Batty shows legions of cities in the top echelons of city ank being swept away as they ae eplaced by competitos, lagely fom othe egions. 4

5 City Size Distibutions fo Measuing Depatues fom Zipf constuct and measue the shapes of cumulative city size distibutions fo the n lagest cities fom st ank size S to the smallest of size S n as a total population distibution T fo all people in cities of size S o geate, whee =,n is city ank Cumulative citypopulation distibution T = R T = S i Rank size powe law M~S Mi α 5

6 City Size Distibutions fo Measuing Depatues fom Zipf This typical fom of the city-size distibution tends towad a powe-law in the tail, with a cossove C whee smalle city sizes tend moe towad an exponential distibution. Cumulative citypopulation distibution T = R T = S i Rank size powe law Mi α 6

7 City Size Distibutions fo Measuing Depatues fom Zipf This typical fom of the city-size distibution tends towad a powe-law in the tail, with a cossove C whee smalle city sizes tend moe towad an exponential distibution. This closely fits the q-exponential, Y q (S x) = Y0 (-(-q)x/κ) /(-q) Cumulative citypopulation distibution T = R T = S i Rank size powe law Mi α 7

8 City Size Distibutions fo Measuing Depatues fom Zipf The q-exponential, Y q (S x) = Y0 (-(-q)x/κ) /(-q) asymptotes towad a powe law in the tail when q>, and levels at smalle city sizes towad a finite uban population Y0 as govened by a cossove paamete κ (kappa). Cumulative citypopulation distibution T = R T = S i Rank size powe law Mi α 8

9 City Size Distibutions fo Measuing Depatues fom Zipf The q-exponential, Y q (S x) = Y0 (-(-q)x/κ) /(-q) asymptotes towad a powe law in the tail when q>, and levels at smalle city sizes towad a finite uban population Y0 as govened by a cossove paamete κ (kappa). Low q fittings fo yeas in cumulative numbe of people [0 3 ] e e e e e Lowe q steepe α in the tail Cumulative citypopulation distibution T = R T = S i Rank size powe law Mi α 9

10 City Size Distibutions fo Measuing Depatues fom Zipf The q-exponential, Y q (S x) = Y0 (-(-q)x/κ) /(-q) asymptotes towad a powe law in the tail when q>, and levels at smalle city sizes towad a finite uban population Y0 as govened by a cossove paamete κ (kappa). High q fittings fo yeas in cumulative numbe of people [0 3 ] e e e e e Highe q flatte α in the tail Cumulative citypopulation distibution T = R T = S i Rank size powe law Mi α 0

11 City Size Distibutions fo Measuing Depatues fom Zipf In shifting to a semilog athe than a log-log plot of T in which the Zipfian is expessed as a staight line, we see that many of the empiical distibutions in semilog ae elatively Zipfian but some bow concavely fom a staight line when α> bins Staightline in semilog fo Zipfian Cumulative citypopulation distibution T = R T = S i Rank size powe law Mi α

12 City Size Distibutions fo Measuing Depatues fom Zipf In shifting to a semilog athe than a log-log plot of T in which the Zipfian is expessed as a staight line, we see that many othe empiical distibutions in semilog bow concavely fom a staight line eithe when α> fo a ank-size powe-law, o when the q-exponential has a highe cossove bins Bowedline in semilog non- Zipfian Cumulative citypopulation distibution T = R T = S i Rank size powe law Mi α 2

13 City Size Distibutions fo Measuing Depatues fom Zipf Eithe way. Log-log o semilog, we cay out cuve fitting to the q-exponential, Y q (S x) = Y0 (-(-q)x/κ) /(-q) and do so with Chandle s lagest histoical cities, , fo China, Euope, Middle Asia in between, and the Mideast. China with Euope China Coefficient Uppe Confidence Limit Lowe Confidence Limit 2.5 Euope CCF Lag Numbe q is usually < 3, and >0 and China q leads Euope q by 50 yeas (diffusion time) 3

14 City Size Distibutions fo Measuing Depatues fom Zipf Middle Asia, caught between China and Euope as connected by the Silk Roads, has a diffeent pofile and inteaction Mideast India Afghanistan China with MidEastIndiaAfghan Euope4 with MidEastIndiaAfghan CCF Coefficient Uppe Confidence 0.9 Limit Lowe Confidence Limit CCF Coefficient Uppe Confidence Limit Lowe Confidence Limit q is usually < 3, and >0 and both China q and Euope q depess the Middle Asia q within 50 yeas (competition?) Lag Numbe Lag Numbe

15 China boosted by Middle Asia q 5

16 Euope not boosted by Middle Asia q 6

17 City Size Distibutions as Measued by q Depatues fom Zipf ae histoically unstable: Middle Asia Mideast India Afghanistan q is usually < 3, and >0 and both China q and Euope q depess the Middle Asia q within 50 yeas (competition?) 7

18 City Size Distibutions as Measued by q Depatues fom Zipf ae 3.0 histoically unstable: Euope Euope q is usually < 3, and >½ and China q leads Euope q by 50 yeas (diffusion time) 8

19 City Size Distibutions as Measued by q Depatues fom Zipf ae histoically unstable: China China q is usually < 3, and >0 and China q leads Euope q by 50 yeas (diffusion time) 9

20 City Size Distibutions as Measued by q Depatues fom Zipf ae coelated with instability: China SPIm with q CCF Coefficient Uppe Confidence Limit Lowe Confidence Limit Chinese SPIm=Sociopolitical Instability (moving aveage) as measued by Intenecine was (Lee 93), 25 yea peiods intepolated fo q 20

21 Conclusion Measue fo deviations fom Zipfian (q, kappa) constucted and fitted to thee Euasian wold egions. Shape paamete q of these distibutions oscillates histoically in longe peiods than expected at andom (detended kappa also). Fall in q away fom Zipfian exploed fo China, found to be stongly coelated with intenecine wafae, moe geneally SP Instability. Vaiations in shape paamete q epesent peiods of stability, instability city distibutions ae histoically unstable. Shape paamete q fo China affects Euope q with 50 yea lag (diffusion of innovation, Silk Route tade). China and Euope q affect Middle Asia q negatively (competition) city size instabilities affect wold-system centes. 2

22 Implications Connect these esults with those of Geoff West, Luis Bettencout and Jose Lobo (Chapte, ISCOM book), showing the enegetic inefficiency of lage cities. That, along with city system instabilities, has implications fo moe sevee consequences as uban population systems gow in size. Enegy inefficiencies that ae cumulative, gowing since the industial evolution sevee global waming with no end in sight. This includes a foot ise in oceans by 22 nd C., and flooding of huge numbe of coastal cities, displacing 0% o moe of wold population. Need to conside new design pinciples fo edesigning cities that ae enegetically efficient in self sustaining local and global systems. 22

23 Policy Reseach on Uban Redesign, Enegy, and Ecosystem With a foot ise in oceans by 22 nd C., and flooding of huge numbe of coastal cities, displacing 0% o moe of wold population and geate infastuctual efficiency enegy inefficiencye of lage cities (and convesely fo smalle cities), need to study edesign of new cities inland in the smalle ange that ae enegetically efficient in self-sustaining local and global systems. Existing cities inland in the lage ange that ae enegetically efficient and sustainable in global systems. 23

24 Cohesive Info.Redesign, Minimum Enegy, and Ecocoupling If the netwok hubs found in cities attact population, then membeship in cohesive netgoups pe capita might be lowe in cities because of centalization, oad design, and now, develope design of sububs. In the ea pio to develope design of segmentay sububs (tee-like intabub steets, apateid in sociopolitical effects), ecological psychology found geate poductive ole density and satisfaction in smalle settlements. This could become a enewed design pinciple. Similaly, in lage cities, cohesive designs could be tested against segmentay apateid pinciples and used in design pinciples fo enegetic and ecological efficiencies and sustainabilities. 24

25 Scaling Issues Good deal of time devoted to finding eliable and unbiased estimates of the q-exponential paametes. Excel solve can be used, solving a whole seies of distibutions at once. Spss /Analyze/Regession/Nonlinea can be used, one distibution at a time. We ae testing a candidate model fo unbiased MLE of the q-exponential. Cuent findings eplicated by diffeent fitting methods. Cucial poblems: Accuacy when thee ae elatively few cases Accuacy and unbiased estimation when the lowe-sized cities ae missing Consistency of esults when thee ae fewe o geate top anked cities. Examination of possible biases in histoical distibutions. 25

26 Replication and Consistency Data fo othe continents beside China will be un against indices of sociopolitical instability. Some such data ae available fom Pete Tuchin. Regional vaiability in q studied fo China in elation to Tuchin s histoical dynamic models. Questions of accuacy of total population data fo China, possibly othe egions. Tests of population peaks fo China show pedicted dynamic lags to changes in SPI indices. Consistency tests wok fo Y0 estimates < Total population, and give estimates of pecentage ubanization that fo China appea to impove on Chinese census estimates. The kappa cossove paamete plays a ole in the dynamics. The Yq distibution is diffeentiable. Use of the deivative allows diect mapping into size-specific pocesses of uban demogaphic change. 26

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