曼昆经济学 Application International Trade.docx

曼昆经济学 Application International Trade.docx

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曼昆经济学ApplicationInternationalTrade

APPLICATION:

INTERNATIONALTRADE

INTHISCHAPTERYOUWILL...

Considerwhat

determineswhetheracountryimports

orexportsagood

Examinewhowinsandwholosesfrominternationaltrade

Learnthatthegainstowinnersfrom

internationaltradeexceedthelossestolosers

Ifyoucheckthelabelsontheclothesyouarenowwearing,youwillprobablyfindthatsomeofyourclothesweremadeinanothercountry.AcenturyagothetextilesandclothingindustrywasamajorpartoftheU.S.economy,butthatisnolongerthecase.Facedwithforeigncompetitorsthatcouldproducequalitygoodsatlowcost,manyU.S.firmsfounditincreasinglydifficulttoproduceandselltextilesandclothingataprofit.Asaresult,theylaidofftheirworkersandshutdowntheirfac-tories.Today,muchofthetextilesandclothingthatAmericansconsumeareim-portedfromabroad.

Thestoryofthetextilesindustryraisesimportantquestionsforeconomicpol-icy:

Howdoesinternationaltradeaffecteconomicwell-being?

Whogainsandwholosesfromfreetradeamongcountries,andhowdothegainscomparetothelosses?

Analyzethewelfareeffectsoftariffs

andimportquotas

Examinethe

argumentspeopleusetoadvocate

traderestrictions

179

Chapter3introducedthestudyofinternationaltradebyapplyingtheprinci-pleofcomparativeadvantage.Accordingtothisprinciple,allcountriescanbene-fitfromtradingwithoneanotherbecausetradeallowseachcountrytospecializeindoingwhatitdoesbest.ButtheanalysisinChapter3wasincomplete.Itdidnotexplainhowtheinternationalmarketplaceachievesthesegainsfromtradeorhowthegainsaredistributedamongvariouseconomicactors.

Wenowreturntothestudyofinternationaltradeandtakeupthesequestions.Overthepastseveralchapters,wehavedevelopedmanytoolsforanalyzinghowmarketswork:

supply,demand,equilibrium,consumersurplus,producersurplus,andsoon.Withthesetoolswecanlearnmoreabouttheeffectsofinternationaltradeoneconomicwell-being.

THEDETERMINANTSOFTRADE

Considerthemarketforsteel.Thesteelmarketiswellsuitedtoexaminingthegainsandlossesfrominternationaltrade:

Steelismadeinmanycountriesaroundtheworld,andthereismuchworldtradeinsteel.Moreover,thesteelmarketisoneinwhichpolicymakersoftenconsider（andsometimesimplement）traderestric-tionsinordertoprotectdomesticsteelproducersfromforeigncompetitors.Weex-amineherethesteelmarketintheimaginarycountryofIsoland.

THEEQUILIBRIUMWITHOUTTRADE

Asourstorybegins,theIsolandiansteelmarketisisolatedfromtherestoftheworld.Bygovernmentdecree,nooneinIsolandisallowedtoimportorexportsteel,andthepenaltyforviolatingthedecreeissolargethatnoonedarestry.

Becausethereisnointernationaltrade,themarketforsteelinIsolandconsistssolelyofIsolandianbuyersandsellers.AsFigure9-1shows,thedomesticpricead-juststobalancethequantitysuppliedbydomesticsellersandthequantityde-mandedbydomesticbuyers.Thefigureshowstheconsumerandproducersurplusintheequilibriumwithouttrade.Thesumofconsumerandproducersurplusmeasuresthetotalbenefitsthatbuyersandsellersreceivefromthesteelmarket.

Nowsupposethat,inanelectionupset,Isolandelectsanewpresident.Thepresidentcampaignedonaplatformof“change”andpromisedthevotersboldnewideas.HerfirstactistoassembleateamofeconomiststoevaluateIsolandiantradepolicy.Sheasksthemtoreportbackonthreequestions:

◆IfthegovernmentallowedIsolandianstoimportandexportsteel,whatwouldhappentothepriceofsteelandthequantityofsteelsoldinthedomesticsteelmarket?

◆Whowouldgainfromfreetradeinsteelandwhowouldlose,andwouldthegainsexceedthelosses?

◆Shouldatariff（ataxonsteelimports）oranimportquota（alimitonsteelimports）bepartofthenewtradepolicy?

PriceofSteel

Equilibriumprice

0

Consumersurplus

Producersurplus

Equilibriumquantity

Domesticsupply

Domesticdemand

QuantityofSteel

Figure9-1

THEEQUILIBRIUMWITHOUTINTERNATIONALTRADE.Whenaneconomycannottradeinworldmarkets,thepriceadjuststobalancedomesticsupplyanddemand.ThisfigureshowsconsumerandproducersurplusinanequilibriumwithoutinternationaltradeforthesteelmarketintheimaginarycountryofIsoland.

Afterreviewingsupplyanddemandintheirfavoritetextbook（thisone,ofcourse）,theIsolandianeconomicsteambeginsitsanalysis.

THEWORLDPRICEANDCOMPARATIVEADVANTAGE

ThefirstissueoureconomiststakeupiswhetherIsolandislikelytobecomeasteelimporterorasteelexporter.Inotherwords,iffreetradewereallowed,wouldIsolandiansendupbuyingorsellingsteelinworldmarkets?

Toanswerthisquestion,theeconomistscomparethecurrentIsolandianpriceofsteeltothepriceofsteelinothercountries.Wecallthepriceprevailinginworldmarketstheworldprice.Iftheworldpriceofsteelishigherthanthedomesticprice,thenIsolandwouldbecomeanexporterofsteeloncetradeispermitted.Isolandiansteelproducerswouldbeeagertoreceivethehigherpricesavailableabroadandwouldstartsellingtheirsteeltobuyersinothercountries.Conversely,iftheworldpriceofsteelislowerthanthedomesticprice,thenIsolandwouldbe-comeanimporterofsteel.Becauseforeignsellersofferabetterprice,Isolandiansteelconsumerswouldquicklystartbuyingsteelfromothercountries.

Inessence,comparingtheworldpriceandthedomesticpricebeforetradein-dicateswhetherIsolandhasacomparativeadvantageinproducingsteel.Thedo-mesticpricereflectstheopportunitycostofsteel:

IttellsushowmuchanIsolandianmustgiveuptogetoneunitofsteel.Ifthedomesticpriceislow,thecostofproducingsteelinIsolandislow,suggestingthatIsolandhasacomparativeadvantageinproducingsteelrelativetotherestoftheworld.Ifthedomesticpriceishigh,thenthecostofproducingsteelinIsolandishigh,suggestingthatforeigncountrieshaveacomparativeadvantageinproducingsteel.

worldprice

thepriceofagoodthatprevailsintheworldmarketforthatgood

AswesawinChapter3,tradeamongnationsisultimatelybasedoncompar-ativeadvantage.Thatis,tradeisbeneficialbecauseitallowseachnationtospe-cializeindoingwhatitdoesbest.Bycomparingtheworldpriceandthedomesticpricebeforetrade,wecandeterminewhetherIsolandisbetterorworseatpro-ducingsteelthantherestoftheworld.

QUICKQUIZ:

ThecountryAutarkadoesnotallowinternationaltrade.InAutarka,youcanbuyawoolsuitfor3ouncesofgold.Meanwhile,inneighboringcountries,youcanbuythesamesuitfor2ouncesofgold.IfAutarkaweretoallowfreetrade,woulditimportorexportsuits?

THEWINNERSANDLOSERSFROMTRADE

Toanalyzethewelfareeffectsoffreetrade,theIsolandianeconomistsbeginwiththeassumptionthatIsolandisasmalleconomycomparedtotherestoftheworldsothatitsactionshavenegligibleeffectonworldmarkets.Thesmall-economyas-sumptionhasaspecificimplicationforanalyzingthesteelmarket:

IfIsolandisasmalleconomy,thenthechangeinIsoland’stradepolicywillnotaffecttheworldpriceofsteel.TheIsolandiansaresaidtobepricetakersintheworldeconomy.Thatis,theytaketheworldpriceofsteelasgiven.Theycansellsteelatthispriceandbeexportersorbuysteelatthispriceandbeimporters.

Thesmall-economyassumptionisnotnecessarytoanalyzethegainsandlossesfrominternationaltrade.ButtheIsolandianeconomistsknowfromexperi-encethatthisassumptiongreatlysimplifiestheanalysis.Theyalsoknowthatthebasiclessonsdonotchangeinthemorecomplicatedcaseofalargeeconomy.

THEGAINSANDLOSSESOFANEXPORTINGCOUNTRY

Figure9-2showstheIsolandiansteelmarketwhenthedomesticequilibriumpricebeforetradeisbelowtheworldprice.Oncefreetradeisallowed,thedomesticpricerisestoequaltheworldprice.Nosellerofsteelwouldacceptlessthantheworldprice,andnobuyerwouldpaymorethantheworldprice.

Withthedomesticpricenowequaltotheworldprice,thedomesticquantitysupplieddiffersfromthedomesticquantitydemanded.ThesupplycurveshowsthequantityofsteelsuppliedbyIsolandiansellers.ThedemandcurveshowsthequantityofsteeldemandedbyIsolandianbuyers.Becausethedomesticquantitysuppliedisgreaterthanthedomesticquantitydemanded,Isolandsellssteeltoothercountries.Thus,Isolandbecomesasteelexporter.

Althoughdomesticquantitysuppliedanddomesticquantitydemandeddiffer,thesteelmarketisstillinequilibriumbecausethereisnowanotherparticipantinthemarket:

therestoftheworld.Onecanviewthehorizontallineattheworldpriceasrepresentingthedemandforsteelfromtherestoftheworld.ThisdemandcurveisperfectlyelasticbecauseIsoland,asasmalleconomy,cansellasmuchsteelasitwantsattheworldprice.

PriceofSteel

Priceaftertrade

Pricebeforetrade

Domesticsupply

Worldprice

Figure9-2

INTERNATIONALTRADEINANEXPORTINGCOUNTRY.Oncetradeisallowed,thedomesticpricerisestoequaltheworldprice.Thesupplycurveshowsthequantityofsteelproduceddomestically,andthedemandcurveshowsthequantityconsumeddomestically.ExportsfromIsolandequalthedifferencebetweenthedomesticquan