year, and it will stay at a rapid speed in the next years. UN-Habitat says energy issue takes

Transcription

1 A SIMULATION RESEARCH ON CHINESE URBANIZATION AND ENERGY COMSUMPTION [M Hong, Admnstraton School, ZheJang Unverst, Hangzhou, P.R.C, , [Zhou We, Automaton Department, Xamen Unverst, Xamen, P.R.C, , ] Abstract: Fast growth of the energ consumpton s ascrbed to jont acton of urbanzaton and ndustralzaton. The urbanzaton s caused b populaton mgratng from rural to urban areas, whch s promoted b the ncome gap between them. We compute the mgraton sze based on rural and urban ncome gap and space dscrepanc of the dstrbuton of populaton and economc actvtes, and further calculate the number of new resdents n ctes. What s more, tang Chnese ndustral structure and energ consumpton n each ndustr nto account, we eplore how energ consumpton unt GDP reduce because of technolog advancement, analse the relevance model of populaton growth and energ demand and predct the future energ demand n each ndustr accordng to populaton data. At the same tme,gven ecologcal envronment developng sustanabl, we dscuss the strateg of energ structure readjustment. Kewords: urbanzaton; ndustralzaton; energ demand;sstem smulaton 1.Introducton Chna s undergong urbanzaton and ndustralzaton on an unprecedented scale. Chnese urbanzaton rate ncreases from 17.9% n 1978 to 44.94% n 007, and grows 0.93 percent per ear, and t wll sta at a rapd speed n the net 0-30 ears. UN-Habtat sas energ ssue taes frst place n the four challenges Chnese urbanzaton facesthe are energ ssue, dsposal of sold waste,montorng sstem and nformaton ntercommuncaton for urban development. The gap between Chnese energ suppl and demand s wdenng wth the progress of urbanzaton and ndustralzaton. Chna becomes a net-mporter of petroleum from It has mported mllon tons olncludng crude ol, product ol, lquefed petroleum gas and others n 008, up 9.5% over the same perod of last ear. Foregn ol taes 50% of domestc ol consumpton n 007,and ol mportng relance reaches up to 5% n 008.Common nternatonal practces show that, f ol mportng relance of a countr reaches or eceeds 50%, t s n earl-warnng perod. Moreover coal and electrc power shortage from 004 to 006 and ol shortage as a result of hgh Ths paper s supported b 1Chnese Mnstr of Educaton human socal scence major project Constructon of Capablt on Copng wth Threat of Non-Tradtonal SecurtNo.08JZD001-D Natonal Populaton and Faml Plannng Commsson Natonal Twelveth Fve-Year Plan Foundaton Quanttatve Analss on Restrcton of Populaton, Resource and Envronment. 3Zhejang Scence Foundaton Innovaton of Management on Water, Land Resources,Capact of Populaton and Regonal Populaton, Resource and Envronment n ZhejangNo.J

2 ol prce n 007 and the frst half ear of 008 sound a warnng to Chnese economc development and socal stablt agan and agan. Chnese fast urbanzaton and ndustralzaton are lad under restrant b energ suppl. The effects the have on energ suppl are tremendous, such as t needs more ct houses, road, all nds of transportaton, water, electrc power and others that populaton develops at top speed to ct and town aggregaton, whch wll ncrease sharpl demand for energ. Almost ever econom goes through a perod of heav and chemcal ndustres durng the modernzaton progress. Some ndustres of ths stage, steel, buldng materal,petrochemcal, metallurg,heav machner, ralwa and car, for eample, develop wth abnormal speed, whch are drven b surgng demand because of urbanzaton. The are hgh-level ntensve on captal and energ, and lead to the fast rse n energ and mabe the nsuffcent energ suppl. Overall, studng the relatonshp between urbanzaton and energ demand quantfcaton all has the mportant realstc sgnfcance and s absolutel necessar n Chna at present..lterature revew Jones,D.W.1991ponts out there are serous of phenomena accompanng the urbanzaton, transformaton from tradtonal agrculture to mechanzed farmng,dvson of labor n dversfed was,space epanson of human and commodtes,change of urban nfrastructure and lfe stle, etc. [1]. Hrou1997analses data of man countres from 1980 to 1993 and fnds there s a postve correlaton between the urbanzaton rate and the logarthm of energ consumpton per capta: energ consumpton structure wll change correspondngl wth the ncrease of popular ncome and total energ demand [].Sathae and Meers1985 refers that along wth the development of urbanzaton, developng countres substtute petroleum for coal more and more frequentl [3]. Dzoubns and Chpman 1999 consder that urbanzaton tend to cause a hgher level of energ consumpton n developng countres. There are two thngs gong n urbanzaton progress: frst thng s transformaton from tradtonal organc fuel to commercal fuel, the net thng s that energ consumpton rato of household electrc applance s gong up [4].As to effect of urbanzaton and energ consumpton on envronment, researches conducted b Parh and others have shown that urbanzaton level and energ consumpton are related to carbon dode emssons. And energ consumpton drectl or ndrectl durng merchandse producton,

3 transportng, fnal energ consumpton and energ converson can lead to global warmng [5]. F. Urban, R.M.J. Benders and H.C. Moll fnd developng countres 'energ consumpton characterstcs are greatl dfferent from the developed countres b comparng twelve energ-econom-envronment models and the estng energ model s put forward based on developed countres condtons, not sutng developng countres. The agrcultural populaton s strongl attached to boenerg and electrc don t full popularze n developng countres [6]. As the largest populaton countr n the world and the thrd-largest econom, Chna s energ consumpton maes up about 16% of the world total and s closel lned wth urbanzaton progress. Geng Haqng 004 carr out the correlaton analss between Chna s energ consumpton of coal,petroleum and natural gas and urbanzaton rato ever ear and fnd ther correlaton coeffcent are all above 0.9 [7]. Gates and Yn stud the relaton between Chnese urbanzaton and energ used b ctzen and commerce. And t shows that urbanzaton needs more electrc wth ts development b analzng urban-rural structure of energ consumpton of electrc home applance, what s more, energ consumpton structure s swtchng from coal and organc fuel to more shares of clean energ tpes such as electrct,natural gas and petroleum [8]. F. Gerard Adams and Yochanan Shachmurove thn Chna wll nevtabl mport more ol coal and gas, but can cut down the mport to a certan etent f dggng up energ-savng potental b rasng energ usng effcenc especall generatng electrct [9]. Le Shen and others 005 consder that Chna s energ effcenc s lower and wll not reach ts urbanzaton goal f the present energ and mnerals consumpton level go on [10]. The estng related researches have eld a rch harvest n terms of urbanzaton energ demand econom and envronment. The have ths characterstc n common: all tae urbanzaton as a macro nde for nstance urbanzaton and analze ts relatonshp wth energ econom and envronment drectl. In fact, the concept of urbanzaton has rch connotaton, consstng of multple factors such as room mbalance of economc actvt and populaton dstrbuton populaton mgraton and the ncome gap between urban areas and rural areas and so on, whch are closel related to energ consumpton. Therefore, ths paper studes urbanzaton progress from ts composton factors respectvel, and emulates the sstem of urbanzaton and energ econom and envronment.

4 3. Smulaton Model Desgn Urbanzaton and ndustralzaton together mpel the energ demand to ncrease. Urbanzaton manl embodes n ncreased urban populaton proporton and ndustralzaton manl embodes n the growth of secondar ndustr and tertar ndustr proporton n natonal econom. Ths paper eplores urbanzaton progress from populaton mgraton from rural areas to urban areas, and then smulates and predcts the energ demand n the future accordng to characterstcs of each ndustr. 3.1 Urbanzaton and Mgraton Model Keftz Nathan, a well-nown demographer, put forward a populaton mgraton model as follows: dpr t r m Pr t dt dp u t mpr t + upu t dt 1 In whch P r t and P u t are the populaton at tme t of the rural and urban areas respectvel, r and u are the natural ncrease rates of the rural and urban areas respectvel, m s net outmgraton rate from rural regons. The soluton of ths model s: r Pr t Pr 0 e mpr 0 Pu t r m u m t r m t ut e e + P 0 e u ut Defne functon Φ t, the urbanzaton rate, thus Pu t Φ t 3 P t + P t r u Keftz model has mportant sgnfcance n theor. It descrbes general law of populaton mgraton from rural to urban areas.but the assumpton of constant rate of natural ncrease and outmgraton rate s ver harsh.so the applcaton of ths model s lmted. In fact natural ncrease and outmgraton rate are not constants and the are nfluenced b socal econom Now we wll establsh sstems dnamcs model to analse parameters nfluence each other. r u and m var wth tme, so the can be denoted b r t u t and m t n sstems dnamcs model. The change rate of rural populaton s drectl proportonal to rural populaton base,whle the change rate of urban populaton s nfluenced b urban populaton base and mgraton populaton. Most of mgraton s caused b socoeconomc factor. So the ncome gap between urban and rural

5 areas must be consdered. Also, the more surplus rural labour,the more the mgrate nto urban areas. Wth the urbanzaton gong on, populaton n rural areas decreases and the proporton of the urban populaton ncreases.when urban populaton proporton reaches certan degree,the speed of urbanzaton wll slow down. So mgraton sze can be seen as drectl proportonal to rural populaton and nversel proportonal to urban populaton. On the bass of the orgnal form, the gravt model can be modfed as r u u r ru PW PW D K M 4 where ru M s mgraton sze from rural to urban areas, K s constant coeffcent, r W and u W are ncome n the rural and urban areas respectvel n Chna, r P and u P are rural populaton and urban populaton, D s spacal dstance between populaton gravt center and economc gravt center of Chna. Gravt center s a pont at whch torque s least n phscs. On a two-dmensonal Cartesan coordnate sstem, gravt center can be determned wth follow equaton: n n n n m m Y m m X In regonal economc research,suppose a regon s composed b n secondar regon, then gravt center of certan attrbute of ths regon can be calculated wth follow equaton: / / M Y M Y M X M X 6 where X and Y are longtude and lattude of gravt center of certan attrbute of a regon respectvel, X and Y are longtude and lattude of gravt center of certan attrbute of a secondar regon respectvel.and n ths paper, X and Y are defned wth geographcal coordnates of captal ctes of provnces n Chna. Regard GDP as economc attrbute when we mae certan economc gravt center.also regard populaton at the end of the ear as populaton dstrbuton attrbute when we mae certan populaton gravt center.

6 After obtan gravt center of economc and populaton,we can calculate the dstance between them wth follow equaton: center, [ C P + C P ] 1/ D N 7 s s where D s spacal dstance between populaton gravt center and economc gravt Ps and P are longtude and lattude of populaton gravt center; C s and C are longtude and lattude of economc gravt center. Transform geographcal coordnates unt:degree nto the value correspondng to plane dstance, denotes wth N. Here N equals Km per degree [11]. Calculate wth populaton and gross domestc product of ever provnces n Chna accordng to Statstcs Yearboo of Chna The result of calculaton s as table 1. Formula4 can be changed to: K M rupw u r 8 PW D r u where W r W u P r P u can be found n Statstcs Yearboo of Chna, and D can be found n Table 1.Then,calculate M ru n method as followng: We can get rural and urban populaton natural ncrease rates respectvel b consderng brthrate and mortalt.suppose P ut s urban populaton at tme t, r s natural ncrease rate ths ear,so P ut 1 + r s urban populaton at tme t + 1 f there s no mgraton from rural areas. Consderng the est of mgraton, net mmgraton of the urban regon s P P r u t + 1 ut 1+.In the same wa,consder outmgraton of the rural regon can get net outmgraton.then, compute the average of net mmgraton of the urban regon and net outmgraton of the rural regon. So,we obtan the mgraton data of the ear The value of K s calculated as table. Table1 Calculate Coeffcent K n the Model. urban rural mgraton Urban rural Dstance Year populaton populaton populaton Income Income 10 4 person Km uan uan /Km K

7 Data from Statstcs Yearboo of Chna The last column n table s coeffcent K of ever ear. K fluctuates between and 1.99, frequenc between 1.81 and 1.88 s most,so K can be regard as constant. Ths result ndcates that the modfed gravt model s consstent wth the fact. Compute the average of K of the ear ,t s person/km. So the modfed gravt model s PW D M 83 j j j 1. 9 PW j r t and u t can be forecasted n demographc mult-factor theor,whle m t can be computed accordng to mgraton sze ever ear. Spacal dstance D between populaton gravt center and economc gravt center n the future wll be deduced b etrapolaton. Fg.1 urbanzaton and mgraton model 3. Urbanzaton-Energ-Econom Model The data are mported nto the urbanzaton-energ-econom smulaton model, whch cover urban and rural populaton, mgraton populaton and percentage of urbanzaton ever ear computed n the urbanzaton smulaton model. Energ consumptons are dvded nto dfferent categores b ndustr accordng to classfcaton standards n Balance of Comprehensve Energ of Chna Statstcal Yearboo and the are as follows: Agrculture,Industr,Constructon,Transport and Storage Servces, Wholesale and Retal Trade, Resdental Consumpton,other. Ths nd of

8 classfcaton s based on energ consumpton characterstcs of each ndustr: for eample, energ consumpton of ndustr s hghl correlated wth GDP per capta,urban populaton sze, urbanzaton rate,the ncome of urban and rural resdents; energ consumpton of agrculture s postvel assocated wth ncome of rural resdents, negatvel wth rural populaton sze, whch s because agrculture need more energ substtuton for labors decrease; Energ consumpton of constructon s manl affected b mgraton sze,the number of urban populaton, percentage of urbanzaton and ncome of urban resdents, and t s apparentl because ncreased urban populaton and ncome requre more houses and nfrastructure facltes. Ke nfluencng factors are selected b factor analss method from transportaton, transport and storage servces wholesale and retal, resdental consumpton. Fg. urbanzaton-energ-econom model Econom development level manl embodes n GDP per capta varable, GDP per capta n the future can be predcted n accordance wth the plan brought up b Chna: GDP per capta n 00 wll quadruple the 000 volume. Chnese GDP per capta n 000 s 7858 Yuan RMB, so the goal s to reach up to 3143 Yuan RMB n 00. In order to realze t, average annual growth must eep 7.%, but n fact, t s mpossbl ncreasng b the same percentage n the followng 0 ears. Data of GDP per capta from 1995 to 006 are ftted b dfferent methods and the best ftted regresson model s the logstc equaton. It s: u 1 + t 1 β 0 β 1 10 In whch t s the forecast ear, s the GDP per capta predcted, u s the upper lmt

9 value, β 0, β1 are model parameters. Parameters values are got b fttng based on tme seres data. Internatonal eperence we have ganed show that growth rate wll decrease graduall after the base of GDP per capta s enlarged. Chna s econom wll grow slower than now n Suppose GDP per capta n 040 double that for 00average growth rate s 3.5%, and then GDP per capta ever ear s ftted nto the logstc regresson equaton. The ncome of urban and rural resdents can be computed b the smlar method. Energ utlzaton effcenc s one of the e ndees affectng energ consumpton demand. Chna s energ consumpton per capta s.7 tmes the world s average level, 4.6 tmes hgh-ncome countres n 005.Lower utlzaton effcenc leads to over consumpton of energ, and wastes produced worsen the eco-envronment. Outlne of the Eleventh Fve-ear Plan on Natonal Economc and Socal Development of the PRC sets a goal to slash ts energ consumpton per unt of domestc gross product b 0 percent between 006 and 010. Furthermore, n the Comprehensve Tas Scheme on Energ Savng and Emssons Curbng of the state councl, t s set forth that energ consumpton for ever ten thousand Yuan worth of the gross domestc product GDP wll decrease from 1. tons of the standard coal n 005 to less than 1 ton n 010, decreasng about 0%. It can be foreseen that energ consumpton per unt of domestc gross product wll contnue to fall after 010 whch has been shown b estng tme seres data. Power functon model can effectvel depct ths law of the curve slopng down, suppose t 1 n 1999,the equaton s: t, R, F Results Run the smulaton of sstem dnamcs wth Vensm software.the output s followng :

10 Fg.3 result of urbanzaton smulaton Accordng to the hstorcal data, Chnese urbanzaton rate ncreases from 17.9% n 1978 to 44.94% n 007 and grows 0.93% ever ear. Rural populaton reaches ts pea number of 859 mllon, and then graduall decreases.populaton n urban areas ncreases contnuousl. It can be found from table 3 that the populaton wll eep ncreasng n urban areas but decreasng n rural areas. Urban populaton eceeds rural populaton n 013. The urbanzaton rate n Chna wll be reach 61.5% n 040 f the trend goes on. As the rural populaton decreases, the sze of mgraton wll fall down, from more than ten mllon n 010 to merel four mllon n 040;the speed of the urbanzaton decreases from 0.8% per ear down to 0.3% per ear. Fg.4 energ demand of ndustr,transportaton and resdental consumpton Fg.5 energ demand of farmng,constructon, wholesale and retal trade, other consumpton Smulaton results of energ demand of dfferent ndustr are shown n fgure 4 and fgure 5. Energ consumpton of ndustr maes greatest contrbuton to the fnal energ consumpton, but because of transformaton of heav chemcal ndustr and technolog advancement, energ consumpton per unt wll go down graduall and then the growth rate of ndustr energ

11 consumpton wll mtgate. As a result of rural labor gong to the urban areas, the agrculture needs more machner whch causes rapd ncrease n energ. Ths conforms to general law of mutual replacement between captal and labor n economcs. Urbanzaton wll gve mpetus to the massve urban nfrastructure and houses constructon, and so a number of steel cement and other materals are needed. To tae 007 for an eample, Chna s GDP accounts for just 6% of the world total, but steel consumpton more than 30% and cement about 55%. What s more, demand for hgh energ consumpton ndustres s nelastc n Chnese urbanzaton progress. Increased urban populaton and resdent s ncome accelerate the popularzaton of durable goods, such as electrcal household applances and faml cars and others and also lead to rapd ncrease n energ demand. Energ demand of the wholesale, retal and caterng ndustr and others also eep rsng because of t, but the ncrease degree s relatvel low. Fg.6 energ total demand n Chna The average growth rate of Chnese econom stas above 10% and demand for energ ncreases rapdl n recent ears. The amount of ts energ consumpton s 13.9 bllon tons standard coals n 000, 6.6 bllon tons standard coals n 007, ncreasng 10.1% ever ear. In spte of that, concerned b space and tme mbalance of energ output and consumpton and energ sstem, there stll est geographcal and seasonal electrc power shortage coal shortage and ol shortage, nfluencng econom development and lfe of resdents. So energ plan and constructon must go faster than econom development. Accordng to the present energ-savng plan and econom development goal, Chnese energ demand wll reach up to 5.4 bllon tons standard coals n 040Fg.6. Followng ths pattern, Chnese energ consumpton for

12 ten thousand Yuan worth of the gross domestc product ma be decreased to tons standard coals n 040, equvalent to half of the 006, whch s n accordance wth the law of decrease n energ consumpton per unt after calculatons. In realt, f energ utlzaton effcenc can not be mproved greatl, the total amount of energ consumpton wll be hundreds of bllons tons standard coals and energ can not be suppled enough to support the modernzaton progress, whch s dffcult to mage. Energ utlzaton effcenc of hgh-ncome countres n 1990 s tons standard coals. B contrast, Chna s must be stll mproved even tang apprecaton of RMB nto account. 4. Dscusson 4.1 Polc nfluence Ths model analses the urbanzaton on the bass of mathematcal demograph and development economcs theores,whle polc effect s not taen nto account. In fact, mgraton from rural to urban areas s obvousl nfluenced b the polc factor n Chna. The progress of the urbanzaton s greatl accelerated snce Chna relaed lmtatons on farmers tang up permanent or temporar jobs n ctes n the md-1980s. For the moment the household regstraton sstem stll ests and there are wde gulfs between the ctes and countres n terms of nfrastructural facltes educatonal opportuntes and socal securt whch wll last a long tme n the future. It needs to be further dscussed what changes would happen to the populaton mgraton f Chna s gong to lberalze the polces on mgraton from the rural to the urban area and mprove the benefts of rural mgrants worers and the publc servces for the rural people. 4. The lmtaton of ct envronmental capact Chnese ctes have been confrontng wth the acute shortage of water and land, and energ consumpton contnues to grow rapdl. What s more, the problems such as traffc congeston water and ar polluton and garbage dsposal are tormentng persstentl most of ctes n Chna. It s beleved that the ncreased populaton per ear n Bejng can form a medum-szed ct. The ncreasng ct sze s brngng heav pressure on ecologcal envronment. Although the urbanzaton s an neorable law governng socal and economc development, Chna, as the frst n terms of the world s most populaton natons, has been facng more complcated ecologcal problems than other countres. In vew pont of sustanable development, the ctes can accommodate lmted amount of mgraton. Consderng ts natural envronment economc development and publc servce, the ct can determnes ts sze of populaton. 4.3 Energ structure Coal accounts for 69.5% n Chnese energ consumpton n 007, petroleum 19.7% and gas

13 3.5%, and hdropower,nuclear power and wnd power sum up to 7.3% [1]. If there has no been change on ths structure, demand for coal wll double n the future and envronment capact can not support ths stuaton. Lots of bproducts Generated b burnng of coal, such as carbon dode sulfur dode ntrogen odes and smoe dust and so on, can deepen greenhouse effect and pollute the atmospherc envronment.chnese prmar energ consumpton accounts for 15.% of the world total, but carbon dode emssons 18.8% n 005. Accordng to relatve calculaton, the amount of Chna s carbon dode could be eceeds Amerca s, beng the world most emssons countr, and emssons of carbon dode per person also come to the world average level, and wll go on growng faster [13]. Therefore, Chnese energ consumpton structure must be adjusted consderabl, the proporton of the coal should be reduced and the rato of hdropower,nuclear power and wnd power wll be ncreased. Gven ts effect on the ecologcal envronment, Chnese hdropower resources eplotaton has formed a certan scale, but ts constructon should be approprate. Wnd power and solar energ utlzaton are developng ver qucl, but the percentage of power capact n the natonal total s farl low. So n the long run, enhancng the proporton of nuclear power s thought of as practcal. The results on the role of nuclear power n carbon abatement suggest that massve carbon abatement depends manl on the development of nuclear power, and f nstalled capact of nuclear power tomorrow can reach 500 GW, the carbon dode wll be decrease 30% [14]. In 007 the state councl ssued Development Plan for Medum and Long Term Nuclear Power Development It s ponted out n ths plan, n 00 the proporton of nuclear power nstalled capact n the natonal total wll ncrease from less than % to 4%, and annual energ producton of nuclear power comes to bllon lowatt-hours. But there s a stll bg gap compared wth developed countres. European power capact accounts for 44.3% n the world total, of North Amerca s 34.7% and Asa-pacfc s 19.9%. In terms of countres respectvel, power capact of Amerca French and Japan amounts to more than a half of total productonup to 57%. Overall, Chnese nuclear power has a broad developng space. As a clean and hgh effectve energ, nuclear power development s one of the most mportant decsons for Chna whch helps to ncrease energ suppl optmze energ structure and deal wth clmate change and nuclear power epanson should be e focus for energ strateg.

14 References: [1] Jones, D. W How urbanzaton affects energ use n developng countres. Energ Polc 19, [] Hrou IMAI. the Effect of Uthanzaton on Energ Consumpton.the Journal of Populaton Problems.1997, 53:43-49 [3]Sathae J.and Meers S.Energ Use n Ctes of the Developng countres. Annual Revew Energ : [4] Oleg Dzoubns and Ralph Chpman.Trends n Consumpton and Producton:Household Energ Consumpton. DESA Dscusson Paper [5]Jot Parh and Vbhoot Shula.Urbanzaton energ use and greenhouse effeets n economc development:results from across natonal stud of developng countres.global Envronmental Change.1995, 5: [6]F. Urban, R.M.J. Benders, H.C. Moll.Modellng energ sstems for developng countres,energ Polc [7] Geng Haqng,Analse of nteract between energ bass and urbanzaton n Chna, Insttute of Geograph of Academa Snca 004, [8]Davd F.Gates and Jason Z.Yn.Urbanzaton and Energ n Chna:Issues and Implcatons.In:Amn Chen, Gordon Lu and Kevn Zhang edtor. Urbanzaton and Soeal Welfare n Chna. Burlngton VT:Ashgate Publshng. 004: [9]F. Gerard Adams 和 Yochanan Shachmurove. Modelng and forecastng energ consumpton n Chna:Implcatons for Chnese energ demand and mports n 00,Energ Economcs : [10]LeShen,Shengu Cheng,Aaron James Gunson. Urbanzaton,Sustanablt and the Utlzaton of Energ and Mneral Resources n Chna.Ctes.005,4:87-30 [11] Lao Xaone,Analss on the Evolvement Trac of Populaton Gravt Center, Emploment Gravt Center and Economc Gravt Center, Populaton Journal, 007,3:3-8. [1] Natonal Bureau of Statstcs. Statstcs Yearboo of Chna007. [13] He Janun,Cha Qmn.Revews on Global Long-term Target of GHG Emsson Mtgaton,Journal of Tsnghua UnverstPhlosoph and Socal Scences, 008,4:15-5. [14] Chen Wenng,Gao Pengfe,He Janun. Impacts of future carbon emsson reductons on the Chnese GDP growth,journal of Tsnghua Unverst Scence and Technolog, 004,446: