经济学原理-Chapter-10ppt课件.ppt

Externalities 10 CHAPTER10EXTERNALITIES Inthischapter lookfortheanswerstothesequestions Whatisanexternality Whydoexternalitiesmakemarketoutcomesinefficient Howcanpeoplesometimessolvetheproblemofexternalitiesontheirown Whydosuchprivatesolutionsnotalwayswork Whatpublicpoliciesaimtosolvetheproblemofexternalities CHAPTER10EXTERNALITIES Introduction RecalloneoftheTenPrinciplesfromChap 1 Marketsareusuallyagoodwaytoorganizeeconomicactivity LessonfromChapter7 Intheabsenceofmarketfailures thecompetitivemarketoutcomeisefficient maximizestotalsurplus CHAPTER10EXTERNALITIES Introduction Onetypeofmarketfailure externalities Externality theuncompensatedimpactofoneperson sactionsonthewell beingofabystanderNegativeexternality theeffectonbystandersisadversePositiveexternality theeffectonbystandersisbeneficial CHAPTER10EXTERNALITIES Introduction Self interestedbuyersandsellersneglecttheexternaleffectsoftheiractions sothemarketoutcomeisnotefficient AnotherprinciplefromChapter1 Governmentscansometimesimprovemarketoutcomes CHAPTER10EXTERNALITIES Pollution ANegativeExternality Exampleofnegativeexternality Airpollutionfromafactory Thefirmdoesnotbearthefullcostofitsproduction andsowillproducemorethanthesociallyefficientquantity Howgovtmayimprovethemarketoutcome Imposeataxonthefirmequaltotheexternalcostofthepollutionitgenerates CHAPTER10EXTERNALITIES OtherExamplesofNegativeExternalities theneighbor sbarkingdoglate nightstereoblastingfromthedormroomnexttoyoursnoisepollutionfromconstructionprojectstalkingoncellphonewhiledrivingmakestheroadslesssafeforothershealthrisktoothersfromsecond handsmoke CHAPTER10EXTERNALITIES PositiveExternalitiesfromEducation Amoreeducatedpopulationbenefitssociety lowercrimerates educatedpeoplehavemoreopportunities arelesslikelytorobandstealbettergovernment educatedpeoplemakebetter informedvotersPeopledonotconsidertheseexternalbenefitswhendecidinghowmucheducationto purchase Result marketeq mquantityofeducationtoolowHowgovtmayimprovethemarketoutcome subsidizecostofeducation CHAPTER10EXTERNALITIES OtherExamplesofPositiveExternalities Beingvaccinatedagainstcontagiousdiseasesprotectsnotonlyyou butpeoplewhovisitthesaladbarorproducesectionafteryou R Dcreatesknowledgeotherscanuse Renovatingyourhouseincreasesneighboringpropertyvalues Thankyoufornotcontaminatingthefruitsupply CHAPTER10EXTERNALITIES RecapofWelfareEconomics Demandcurveshowsprivatevalue thevaluetobuyers thepricestheyarewillingtopay Supplycurveshowsprivatecost thecostsdirectlyincurredbysellers Themarketeq mmaximizesconsumer producersurplus CHAPTER10EXTERNALITIES AnalysisofaNegativeExternality Supply privatecost Externalcost valueofthenegativeimpactonbystanders 1pergallon valueofharmfromsmog greenhousegases Socialcost private externalcost CHAPTER10EXTERNALITIES AnalysisofaNegativeExternality D S Socialcost Thesociallyoptimalquantityis20gallons AtanyQ 20 valueofadditionalgasexceedssocialcost AtanyQ 20 socialcostofthelastgallonisgreaterthanitsvalue 25 CHAPTER10EXTERNALITIES AnalysisofaNegativeExternality D S Socialcost Marketeq m Q 25 isgreaterthansocialoptimum Q 20 25 Onesolution taxsellers 1 gallon wouldshiftsupplycurveup 1 CHAPTER10EXTERNALITIES InternalizingtheExternality Internalizingtheexternality alteringincentivessothatpeopletakeaccountoftheexternaleffectsoftheiractionsInourexample the 1 gallontaxonsellersmakessellers costs socialcosts Whenmarketparticipantsmustpaysocialcosts marketeq m socialoptimum Imposingthetaxonbuyerswouldachievethesameoutcome marketQwouldequaloptimalQ CHAPTER10EXTERNALITIES PositiveExternalities Inthepresenceofapositiveexternality thesocialvalueofagoodincludesprivatevalue thedirectvaluetobuyersexternalbenefit thevalueofthepositiveimpactonbystandersThesociallyoptimalQmaximizeswelfare AtanylowerQ thesocialvalueofadditionalunitsexceedstheircost AtanyhigherQ thecostofthelastunitexceedsitssocialvalue ACTIVELEARNING1 Analysisofapositiveexternality 15 Themarketforflushots D S Externalbenefit 10 shotDrawthesocialvaluecurve FindthesociallyoptimalQ Whatpolicywouldinternalizethisexternality ACTIVELEARNING1 Answers SociallyoptimalQ 25shotsTointernalizetheexternality usesubsidy 10 shot 16 Themarketforflushots D S Socialvalue privatevalue externalbenefit CHAPTER10EXTERNALITIES IfnegativeexternalitymarketquantitylargerthansociallydesirableIfpositiveexternalitymarketquantitysmallerthansociallydesirableToremedytheproblem internalizetheexternality taxgoodswithnegativeexternalitiessubsidizegoodswithpositiveexternalities EffectsofExternalities Summary CHAPTER10EXTERNALITIES PrivateSolutionstoExternalities Typesofprivatesolutions moralcodesandsocialsanctions e g the GoldenRule charities e g theSierraClubcontractsbetweenmarketparticipantsandtheaffectedbystandersE g abeekeeperandappleorchardmanagereachagreetoboostproduction aseachproducer sactivityconfersanexternalbenefitontheother CHAPTER10EXTERNALITIES PrivateSolutionstoExternalities TheCoasetheorem Ifprivatepartiescancostlesslybargainovertheallocationofresources theycansolvetheexternalitiesproblemontheirown CHAPTER10EXTERNALITIES TheCoaseTheorem AnExample DickownsadognamedSpot Negativeexternality Spot sbarkingdisturbsJane Dick sneighbor ThesociallyefficientoutcomemaximizesDick s Jane swell being IfDickvalueshavingSpotmorethanJanevaluespeace quiet thedogshouldstay Coasetheorem Theprivatemarketwillreachtheefficientoutcomeonitsown SeeSpotbark CHAPTER10EXTERNALITIES TheCoaseTheorem AnExample CASE1 DickhastherighttokeepSpot BenefittoDickofhavingSpot 500CosttoJaneofSpot sbarking 800Sociallyefficientoutcome Spotgoesbye bye Privateoutcome JanepaysDick 600togetridofSpot bothJaneandDickarebetteroff Privateoutcome efficientoutcome CHAPTER10EXTERNALITIES TheCoaseTheorem AnExample CASE2 DickhastherighttokeepSpot BenefittoDickofhavingSpot 1000CosttoJaneofSpot sbarking 800Sociallyefficientoutcome SeeSpotstay Privateoutcome Janenotwillingtopaymorethan 800 Dicknotwillingtoacceptlessthan 1000 soSpotstays Privateoutcome efficientoutcome CHAPTER10EXTERNALITIES TheCoaseTheorem AnExample CASE3 Janehasthelegalrighttopeace quiet BenefittoDickofhavingSpot 800CosttoJaneofSpot sbarking 500Sociallyefficientoutcome DickkeepsSpot Privateoutcome DickpaysJane 600toputupwithSpot sbarking Privateoutcome efficientoutcome Theprivatemarketachievestheefficientoutcomeregardlessoftheinitialdistributionofrights ACTIVELEARNING2 Brainstorming Collectively the1000residentsofGreenValleyvalueswimminginBlueLakeat 100 000 Anearbyfactorypollutesthelakewater andwouldhavetopay 50 000fornon pollutingequipment A DescribeaCoase likeprivatesolution B Canyouthinkofanyreasonswhythissolutionmightnotworkintherealworld 24 CHAPTER10EXTERNALITIES WhyPrivateSolutionsDoNotAlwaysWork 1 Transactioncosts Thecostspartiesincurintheprocessofagreeingtoandfollowingthroughonabargain Thesecostsmaymakeitimpossibletoreachamutuallybeneficialagreement 2 Stubbornness Evenifabeneficialagreementispossible eachpartymayholdoutforabetterdeal 3 Coordinationproblems If ofpartiesisverylarge coordinatingthemmaybecostly difficult orimpossible 1 Transactionscosts Supposelawyerscharge 60 000torepresentthetwopartiesanddrawupacontractthatisenforceableinacourt Thenitwillbeimpossibleforbothpartiestocometoamutuallybeneficialagreement andthefactorywillcontinuepollutingthelake 2 Stubbornness Supposethetownoffers 55 000tothefactory Thefactorywouldbebetterofftakingthisofferthannothingatall butthefactorymaycounterwitha 95 000price Bothpartiesholdoutinhopesthattheotherwillcede butneitherdoes Thefactorykeepspolluting andtheresidentsofGreenValleycontinuetobedeniedthejoyofswimminginthelake 3 Coordinationproblems Gettingall1000residentstoagreetoaspecificofferwillbedifficult Moreover eachresidenthasanincentivetofree rideoffhisneighbors CHAPTER10EXTERNALITIES PublicPoliciesTowardExternalities TwoapproachesCommand and controlpoliciesregulatebehaviordirectly Examples limitsonquantityofpollutionemittedrequirementsthatfirmsadoptaparticulartechnologytoreduceemissionsMarket basedpoliciesprovideincentivessothatprivatedecision makerswillchoosetosolvetheproblemontheirown CHAPTER10EXTERNALITIES Market BasedPolicy 1 CorrectiveTaxes Subsidies Correctivetax ataxdesignedtoinduceprivatedecision makerstotakeaccountofthesocialcoststhatarisefromanegativeexternalityAlsocalledPigouviantaxesafterArthurPigou 1877 1959 Theidealcorrectivetax externalcostForactivitieswithpositiveexternalities idealcorrectivesubsidy externalbenefit CHAPTER10EXTERNALITIES Market BasedPolicy 1 CorrectiveTaxes Subsidies Example Acme USElectricruncoal burningpowerplants Eachemits40tonsofsulfurdioxidepermonth SO2causesacidrain otherhealthissues Policygoal reducingSO2emissions25 Policyoptionsregulation requireeachplanttocutemissionsby25 correctivetax MakeeachplantpayataxoneachtonofSO2emissions Settaxatlevelthatachievesgoal CHAPTER10EXTERNALITIES Market BasedPolicy 1 CorrectiveTaxes Subsidies SupposecostofreducingemissionsislowerforAcmethanforUSElectric Sociallyefficientoutcome AcmereducesemissionsmorethanUSElectric Thecorrectivetaxisapriceontherighttopollute Likeotherprices thetaxallocatesthis good tothefirmswhovalueitmosthighly USElectric CHAPTER10EXTERNALITIES Market BasedPolicy 1 CorrectiveTaxes Subsidies Underregulation firmshavenoincentivetoreduceemissionsbeyondthe25 target Ataxonemissionsgivesfirmsincentivetocontinuereducingemissionsaslongasthecostofdoingsoislessthanthetax Ifacleanertechnologybecomesavailable thetaxgivesfirmsanincentivetoadoptit CHAPTER10EXTERNALITIES Market BasedPolicy 1 CorrectiveTaxes Subsidies Othertaxesdistortincentivesandmoveeconomyawayfromthesocialoptimum Butcorrectivetaxesenhanceefficiencybyaligningprivatewithsocialincentives CHAPTER10EXTERNALITIES ExampleofaCorrectiveTax TheGasTax Thegastaxtargetsthreenegativeexternalities congestionthemoreyoudrive themoreyoucontributetocongestionaccidentslargervehiclescausemoredamageinanaccidentpollutionburningfossilfuelsproducesgreenhousegases ACTIVELEARNING3 Discussionquestion Policygoal ReducinggasolineconsumptionTwoapproaches A Enactregulationsrequiringautomakerstoproducemorefuel efficientvehiclesB Significantlyraisethegastax 34 Discussthemeritsofeachapproach Whichdoyouthinkwouldachievethegoalatlowercost Whodoyouthinkwouldsupportoropposeeachapproach 1 Ifconsumersdemandgas guzzlingSUVsinsteadoffuel efficientcompactsedans thenforcingautomakerstoproducemoreofthelatterwillnotbethebestwaytoachievethegoal 2 Raisingthegastaxwouldshiftconsumerdemandtowardmorefuel efficientvehicles andself interestedautomakerswouldrespondbyproducingmorefuel efficientvehicles 3 TheU S cannotimposemileagerestrictionsonforeignautomakers Itcan however restrictimportsofforeignvehiclesdeemedinefficient ButthiswouldriskWTOsanctionsorretaliatorytraderestrictionsongoodsproducedintheU S 4 PeoplewhodrivemorethanaveragearelikelytopreferAtoB Itmightnotbecost effectiveforaverageJoestoorganize wecouldlikelyexpectthetruckingindustrytolobbymembersofCongresstosupportoptionAandopposeoptionB 5 ManyenvironmentalistswouldlikelysupportB butwouldlikelyopposetheendofregulationsonautomakers CHAPTER10EXTERNALITIES Market BasedPolicy 2 TradablePollutionPermits Recall Acme USElectriceachemit40tonsSO2 totalof80tons Goal reduceemissions25 to60tons month Supposecostofreducingemissionsis 100 tonforAcme 200 tonforUSElectric Ifregulationrequireseachfirmtoreduce10tons costtoAcme 10tons x 100 ton 1 000costtoUSE 10tons x 200 ton 2 000totalcostofachievinggoal 3 000 CHAPTER10EXTERNALITIES Market BasedPolicy 2 TradablePollutionPermits Alternative issue60permits eachallowsitsbeareronetonofSO2emissions sototalemissions 60tons give30permitstoeachfirmestablishmarketfortradingpermitsEachfirmcanchooseamongtheseoptions emit30tonsofSO2 usingallitspermitsemit30tons CHAPTER10EXTERNALITIES Market BasedPolicy 2 TradablePollutionPermits Supposemarketpriceofpermit 150Onepossibleequilibrium Acmespends 2 000tocutemissionsby20tonshas10unusedpermits sellsthemfor 1 500netcosttoAcme 500USElectricemissionsremainat40tonsbuys10permitsfromAcmefor 1 500netcosttoUSE 1 500Totalcostofachievinggoal 2 000 CHAPTER10EXTERNALITIES Market BasedPolicy 2 TradablePollutionPermits Asystemoftradablepollutionpermitsachievesgoalatlowercostthanregulation Firmswithlowcostofreducingpollutionsellwhateverpermitstheycan Firmswithhighcostofreducingpollutionbuypermits Result Pollutionreductionisconcentratedamongthosefirmswithlowestcosts CHAPTER10EXTERNALITIES TradablePollutionPermitsintheRealWorld SO2permitstradedintheU S since1995 NitrogenoxidepermitstradedinthenortheasternU S since1999 CarbonemissionspermitstradedinEuropesinceJanuary1 2005 CHAPTER10EXTERNALITIES CorrectiveTaxesvs TradablePollutionPermits Likemostdemandcurves firms demandfortheabilitytopolluteisadownward slopingfunctionofthe price ofpolluting Acorrectivetaxraisesthispriceandthusreducesthequantityofpollutionfirmsdemand Atradablepermitssystemrestrictsthesupplyofpollutionrights hasthesameeffectasthetax Whenpolicymakersdonotknowthepositionofthis