Science energy ethics and civilization vaclav smil The laser is a perfect example of doing - PDF document

Science,energy,ethics,andcivilizationvaclavsmilThelaserisaperfectexampleofdoingmorewithless–andofdoingitmorepreciselyandmoreaffordablyyetwithreducedundesirableimpacts.Assuch,itbelongstothatremarkableclassofinventionsthathavetransformedourcivilizationincountlessunforeseenways.Atthesametime,allofthesescienticinnovationshavealsoreinforcedandacceleratedthefundamentalhistorictrendtowardhigherpercapitauseofenergy.Thisquestcanbeseenasperhapsthemostimperativedynamicofhumanity.Inthischapter,Itakeacloserlookatthistrendofincreasedenergyuseandconsideritsproblematicsocial,economic,andenvironmentalconsequences.Inconclusion,Ioutlinetheneedtoenditbeforeitcompromisesthehabitabilityofthebiosphere.35.1Humanenergyuse:anevolutionarytrendwithauniqueoutcomeIn1922AlfredLotka(1880–1949)formulatedhislawofmaximizedenergyows:Ineveryinstanceconsidered,naturalselectionwillsooperateastoincreasethetotalmassoftheorganicsystem,toincreasetherateofcirculationofmatterthroughthesystem,andtoincreasethetotalenergyuxthroughthesystemsolongasthereispresentandunutilizedresidueofmatterandavailableenergy(Lotka,1922,p.148).Thegreatestpossibleuxofusefulenergy,themaximumpoweroutput(ratherthanthehigh-estconversionefciency)thusgovernsthegrowth,reproduction,maintenance,andradiationofspeciesandcomplexicationofecosystems.Thephysicalexpressionofthistendencyis,forexample,thesuccessionalprogressionofvegetationcommunitiestowardclimaxecosystemsthatmaximizetheirbiomasswithinthegivenenvironmentalconstraints–althoughmanyenvironmentaldisturbancesmaypreventanecosystemfromreachingthatidealgoal.IntheeasternUnitedStates,anunusuallypowerfulhurricanemayuprootmostofthetreesbeforeanold-growthforestcanmaximizeitsbiomass.Humansocietiesare,fundamentally,complexsubsystemsofthebiosphereandhencetheirevolutionalsotendstomaximizetheirbiomass,theirrateofcirculationofmatter,andhencethetotalenergyuxthroughthesystem(Smil,2007). VisionsofDiscovery:NewLightonPhysics,Cosmology,andConsciousness,ed.R.Y.Chiao,M.L.Cohen,A.J.Leggett,W.D.Phillips,andC.L.Harper,Jr.PublishedbyCambridgeUniversityPress.©CambridgeUniversityPress2010. Science,energy,ethics,andcivilization Fig.35.2.Typicalpercapitaenergyconsumptionratesduringthepast12,000years.solarradiation(owingwaterandwind)orthatharnesseditintheformofbiomassandmetabolicconversionsthattookjustafewmonths(cropsharvestedforfoodandfuel),afewyears(draftanimals,humanmuscles,shrubs,youngtrees),orafewdecades(maturetrees)togrowbeforebecomingusable.Incontrast,fossilfuelswereformedthroughslowbutprofoundchangesofaccumulatedbiomassunderpressure;exceptforyoungpeat,theyrangeinagefrom10to10years.Ausefulanalogyistoseetraditionalsocietiesasrelyingoninstantaneousorminimallydelayedandconstantlyreplenishedsolarincome.Bycontrast,themoderncivilizationiswithdrawingaccumulatedsolarcapitalatratesthatwillexhaustitinatinyfractionofthetimeneededtocreateit.Traditionalsocietieswerethus,atleastintheory,energeticallysustainableonaciv-ilizationaltimescaleof10years,thoughinpracticemanyofthemcausedexcessivedeforestationandsoilerosionandovertaxedtheirlabor.Incontrast,moderncivilizationrestsonindubitablyunsustainableharnessingofauniquesolarinheritancethatcannotbereplenishedonthecivilizationaltimescale.Thisdependencehasgivenusaccesstoenergyresourcesthat,unlikesolarradiation,arebothhighlyconcentratedandeasytostoreandthatcanbeusedatsteadilyhigheraveragerates.Relianceonfossilfuelshasremovedthelimitthattheinherentlylowphotosyntheticefciencyandlow-levelconversionsofanimate,water,andwindenergiesimposedonhumanenergyconsumption.Asaresult,thetotalenergyuxthroughcivilizationhasrisensteadilytounprecedentedlevels(Fig.35.2).Preagriculturalsocietiesconsumedonlyaround10GJ/year,roughlydividedbetweenfoodandphytomassforopenres.BythetimeofEgypt’sNewKingdom(1500BCE),the Science,energy,ethics,andcivilizationoffossilfuelsmorethanquadrupled.Thissecularascenthasbeenevenmoreimpressivewhenexpressedintermsofusefulenergy.Continuingtechnicaladvanceshaveimprovedtypicalefcienciesofallprincipalcommercialenergyconversions,manyofthembyanorderofmagnitude.Actuallydeliveredenergyservices(heat,light,motion)thusgiveatruerimpressionoftherisingenergyuxthandogrossprimaryenergyinputs.Spaceheatingillustrateswelltheseefciencygains.Traditionalhearthsandreplaceshadefcienciesbelow5%.Woodstoveswereusuallylessthan20%efcient.Coalstovesdoubledthatrate,andfuel-oilfurnacesbroughtittonearly50%.Efcienciesofnatural-gasfurnaceswereinitiallybelow60%,butbythe1990stherewasalargeselectionoffurnacesratedatabout95%.Lightingprovidesanevenbetterillustrationoftheriseofusefulenergies(Fig.35.4).Ancientsourcesofillumination(oillamps,candles)weretheonlyoptionavailableuntiltheearlynineteenthcentury,whentherstcoal-gaslightswereintroduced.Candlesandoillampshadconversionefciencies(chemicaltoelectromagneticenergy)oftheorderof0.01%.Therstcoal-gaslightswereabout0.04%efcient.Bycontrast,today’scommonsourcesofilluminationhaveefcienciesofupto15%(foruorescentlights),withamaximumof25%forhigh-pressuresodiumlamps.Inafuentcountries,theoverallefcienciesofprimaryenergyusenearlytripledduringthetwentiethcentury.Astheymovedfromprimitivehearthsandclaystovestonaturalgas,andfromsteamenginestogasturbines,poorindustrializingcountriessawtheiroverallenergy-conversionefciencieseasilyquadrupledduringthetwentiethcentury.Evenwithaconservativeassumptionoftripledconversionefciency,averageglobalpercapitaowofusefulenergieshasincreasedatleastsevenfoldsince1900andoftheorderoftwentyfoldsince1800.Anotherwaytoillustratetheincreasedenergyuseinmodernsocietiesistocontrasttheowscontrolleddirectlybyindividualsinthecourseoftheirdailyactivities,asdescribedbelow.In1800,aNewEnglandfarmerusingtwooxentoplowhisstonyeldcontrolledabout500Wofanimateenergy.In1900,aprosperousGreatPlainsfarmercontrolled5kWofsustainedanimatepowerasheheldthereinsofsixlargehorseswhenplowinghiselds.In2000,hisgreat-grandsonperformedthesametaskintheair-conditionedcomfortoftheinsulatedcabinonahugetractorcapableof300kW.In1800,acoachdrivercontrolledabout2.5kWofhorsepoweronanintercityroute.In1900,anengineeroperatedasteamlocomotivealongthesameroute,commandingabout1MWofsteampower.In2000,acaptainofaBoeing737yingbetweenthesametwocitiescouldleaveittoonboardmicroprocessorstocontroltwojetengineswhoseaggregatecruisepoweraddeduptoabout10MW.Asweepacrosstheentirehistoryofcivilizationshowsthatthepeakunitcapacitiesofprimemoversroseabout15milliontimesin3,000years–from100Wofsustainedhumanlaborto1.5GWforthelargeststeamturbogenerators–withmorethan99%oftherisetakingplaceduringthetwentiethcentury(Figs.35.5(a)and(b)).Acomparisonofenergycostsmakesitclearthattheracetothetopalsoappliestoenergiesembodiedincommonly Science,energy,ethics,andcivilization (a)(b) Fig.35.5.Maximumpowerofprimemoversduringthepast3,000years.2001$)consumednearly40%moreenergyforheating,airconditioning,andappliancesthanthosewithannualincomesbelow$15,000(USEnergyInformationAdministration,2001).Butdirecthouseholduseisonlyasmallpartofoverallenergyconsumption.MillionsofAmerica’shigh-incomefamilies(therearenearly10millionhouseholdswithannualincomesofmorethan$100,000)nowhaveseveralcars,whosemostpowerfulversionsexceed500kW,comparedwithaHondaCivicat104kW.Theenergycostoftheirextensiveairtravelalonemayproratetomorerenedfuelpermonththanmostfamiliesuseintheircarsperyear.35.2ConsumptioninequitiesandtheirimplicationsThetrendtowardhigherenergythroughputshasbeenuniversal,buttheprocesshasbeenproceedingataveryunevenpace,withafuentcountriesclaimingdisproportionatesharesofmodernenergies.In1900,theirshareoftheglobalconsumptionofcommercialener-gies(fossilfuelsandprimaryelectricity)wasabout98%.AtthattimemostpeopleinAsia,Africa,andLatinAmericadidnotusedirectlyanymodernenergies.Verylittlehadchangedduringthersthalfofthetwentiethcentury–by1950,industrializedcountriesstillcon-sumedabout93%oftheworld’scommercialenergy.SubsequenteconomicdevelopmentinAsiaandLatinAmericanallybeganreducingthisshare.However,in2000afuentcountries,containingjust20%oftheglobalpopulation,claimednolessthanabout70%ofcommercialTPES.TheUnitedStates,withlessthan5%oftheworldpopulation,consumedabout27%oftheworld’scommercialTPESin2000,andG7countries(theUnitedStates,Japan,Germany,France,theUK,Italy,andCanada),whosepopulationaddsuptojustabout10%oftheworld’stotal,claimedabout45%(Fig.35.6).Incontrast,thepoorestquarterof VaclavSmil Fig.35.6.Pronouncedinequitiesofglobalenergyconsumption.mankind–thepopulationsofsomefteensub-SaharanAfricancountries,Nepal,Bangladesh,thenationsofIndochina,andmostofruralIndia–consumedamere2.5%,andthepoorestpeopleinthepoorestcountries(severalhundredmillionadultsandchildrenincludingsubsistencefarmers,landlessruralworkers,anddestituteandhomelesspeopleinexpandingmegacities)stilldonotconsumedirectlyanycommercialfuelsorelectricityatall.Nationalaveragesshowthatatthebeginningofthetwenty-rstcenturyannualcon-sumptionratesofcommercialenergyrangedfromlessthan0.5GJpercapitainthepoorestcountriesofsub-SaharanAfrica(Chad,Niger)tomorethan330GJpercapitaintheUnitedStatesandCanada.Theglobalmeanwasabout65GJpercapita,butonlythreecountries–Argentina,Croatia,andPortugal–hadnationalaveragesclosetoit.Persistentconsumptiondisparitiesresultinahyperbolicdistributionofaveragepercapitaenergyuse,withthemodalvalue(includingathirdofallcountries)oflessthan10GJpercapita(Fig.35.6).Withlessthanasixthofallhumanityenjoyingthebenetsofthehigh-energycivilization,athirdofitisnowengagedinafranticracetojointhatminority,andmorethanhalfoftheworld’spopulationhasyettobeginthisascent.Thepotentialneedformoreenergyisthusenormous.However,asthefollowingcalculationindicates,theprobabilityofclosingthegapduringthecomingoneortwogenerationsisnil.TheutterlyimpossibleoptionistoextendthebenetsoftwoNorthAmericanhigh-energysocieties(about330millionpeopleconsumingannuallysome330GJpercapita)totherestoftheworld(about6.5billionpeoplein2005).Thiswouldrequirenearly2.3ZJofprimaryenergy,orslightlymorethanvetimesthecurrentglobalsupply.Neithertheknownresourcesoffossilfuelsnortheavailableandprospectiveextractionandconversiontechniquescouldsupplysuchanenergyuxby2030or2050.TheJapanesemeanofabout170GJpercapitaisthesameasthatoftherichesteconomiesoftheEU.Itsextensionto6.5billionpeoplewouldrequireabout1.1ZJ,or2.5timesthecurrentlevel.Thislevelismorerealistictocontemplate,butitseventualachievementwould,withoutaradicalchangeoftheprimaryenergycomposition,leadtounacceptablyhighlevelsofCOemissions.Inordertokeepthefutureglobalwarmingwithinacceptablelimits,concentrationsofatmosphericCOshouldbekeptbelow500ppm(theyhadsurpassed VaclavSmil Fig.35.7.AveragefuelconsumptionandaveragedistancedrivenperUScar,1965–2005.comparedwiththevehiclesofthemid1970s.Inreality,thetrendshavebeenintheoppositeAsforthemass,nearlyhalfofthepassengervehiclesofchoicearenotevencars,sinceSUVsandpick-upsareclassiedinthe“lighttruck”category.Thesevehiclescommonlyweighbetween2and2.5t,withthelargestonestopping4t,comparedwith0.9–1.3tforcompactcars.Fuelconsumptionincitydriving(wheretheyaremostlyused)commonlysurpasses15Lper100km(20Lper100kmforsomevehicles);forcomparison,efcientsubcompactsneedlessthan8L/km,andcompactsaveragearound10L/km.Butthesecars,too,havebecomeheavierandmorepowerfulthanagenerationago.My2006HondaCivicismorepowerfulandheavierthanmyHondaAccordof20yearsago.Moreover,theaveragedistancedrivenperyearkeepsincreasing(Fig.35.7).IntheUS,itisnowaround20,000kmpermotorvehicle,upbyabout30%between1980and2000(BureauofTransportationStatistics,2007),ascommuteshavelengthenedandasmoretouringtripstoremotedestinationsaretaken.ThenetoutcomeofallofthisisthatAmerica’smotorvehiclesconsumed35%moreenergyin2000perlicenseddriverthantheydidin1980.Inaggregate,theseefciencygainshavetranslatedintocontinuingdeclinesintheenergyintensityofnationaleconomies,theamountofprimaryenergyconsumedtogenerateaunitofGDP(Fig.35.8).Despitethistrend,however,theaveragepercapitaconsumptionofenergyhasbeenrisingeverywhere–notonlyinsuchrapidlyindustrializingnationsasChina,butalsoincountrieswheretheseratesarealreadyveryhigh,asillustratedbytheUSandJapaneseexamplesinFig.35.9. VaclavSmil Fig.35.10.Globaluxofrenewableenergiescomparedwithglobalfossil-fuelconsumption.35.4Renewableenergies:problemsofscaleandpowerdensityInsolation(at122PW)istheonlyrenewableux;itisnearlyfourordersofmagnitudegreaterthantheworld’sTPESofnearly13TWintheyear2000(Fig.35.10).Nolessimportantly,directsolarradiationistheonlyrenewableenergyuxavailablewithpowerdensitiesof10(globalmeanofabout170Wm),whichmeansthatincreasingefcienciesofitsconversion(aboveallbetterphotovoltaics)couldharnessitwitheffectivedensitiesof10;thebestall-dayratesin2005wereoftheorderof30WmAllotherrenewableowsareharnessedwithpowerdensitiesthatareonetothreeordersofmagnitudelowerthanthetypicalpowerdensitiesofenergyconsumptioninmodernsocieties(Fig.35.11).Butdirectsolarconversionswouldsharetwokeydrawbackswithotherrenewables:lossoflocationexibilityofelectricity-generatingplantsandinherentstochasticityofenergyows.Thesecondrealityposesaparticularlygreatchallengetoanyconversionsystemaimingatasteady,andhighlyreliable,supplyofenergyasisrequiredbymodernindustrial,commercial,andresidentialinfrastructures.Terrestrialnetprimaryproductivity(NPP)of55–60TWisnearlyvetimesaslargeaswastheglobalTPESin2005,butproposalsofmassivebiomassenergyschemesareamongthemostregrettableexamplesofwishfulthinkingandignoranceofecosystemicrealitiesandnecessities.Theirproponentsareeitherunawareof(ordeliberatelyignore)threefundamentalndingsofmodernbiosphericstudies.First,astheMillenniumEcosystemAssessment(2005)demonstrated,essentialecosys-temicservices(withoutwhichtherecanbenoviableeconomies)havealreadybeenmod-ied,reduced,andcompromisedtoaworrisomedegree.Massive,intensivemonoculturalplantingsofenergycropscouldonlyacceleratetheirdecline. Science,energy,ethics,andcivilization Fig.35.11.MismatchbetweenpowerdensitiesofenergyconsumptionandrenewableenergySecond,humansalreadyappropriate30%–40%ofallNPPasfood,feed,ber,andfuel,withwoodandcropresiduessupplyingabout10%oftheTPES(Rojstaczeretal.,2001).Moreover,highlyunequaldistributionofthehumanuseofNPPmeansthatthephytomassappropriationratiosaremorethan60%ineastAsiaandmorethan70%inwesternEurope(Imhoffetal.,2004).Claimsthatsimpleandcost-effectivebiomassapproachescouldprovide50%oftheworld’sTPESby2050orthat1–2Gtofcropresiduescanbeburnedeveryyearwouldputthehumanappropriationofphytomassclosetoorabove50%ofterrestrialphotosynthesis.Thiswouldfurtherreducethephytomassavailableformicrobesandwildheterotrophs,eliminateorirreparablyweakenmanyecosystemicservices,andreducetherecyclingoforganicmatterinagriculture.Onlyanutterlybiologicallyilliteratemindcouldrecommendsuchaction.Finally,nitrogenisalmostalwaysthecriticalgrowth-limitingmacronutrientininten-sivelycultivatedagroecosystemsaswellasinsilviculture.Massproductionofphytomassforconversiontoliquidfuels,gases,orelectricitywouldnecessitateasubstantialincreaseincontinuousapplicationofthiselement.Proponentsofmassivebioenergyschemesappeartobeunawareofthefactthatthehumaninterferenceintheglobalnitrogencyclehasalreadyvastlysurpassedtheproportionalanthropogenicchangeincarboncycle.Thesurfeitofreactivenitrogen–dissolvedinprecipitation,drydeposited,causingspreadingcontami-nationandeutrophicationoffreshandcoastalwaters,escapingasNOviadenitrication,andchangingthespeciccompositionofsensitiveecosystems–isalreadythecauseofanundesirablebiosphere-widechange(Smil,2002).Minimizinganyfurtherinterference VaclavSmil Fig.35.14.Percapitaenergyuseandmalnutrition.theproportionofundernourishedpeople,anindicatorthatcapturestheprogressbeyondthemini-mumexistentialrequirements(Fig.35.14).Inallofthese(andnumerousother)cases,therearepronouncedgainsascommercialenergyuseincreasestoward30and40GJpercapita,andclearinectionsareevidentatannualconsumptionlevelsof50–60GJpercapita;theseinectionsarefollowedbyrapidlydiminishingreturnsandnallybyazoneofnoadditionalgainsaccompanyingprimarycommercialenergyconsumptionabove100–110GJpercapita.ThepatternchangesonlyalittlewhentheplotisdoneforanaggregateHumanDevelopmentIndex(HDI)favoredbytheUnitedNationsDevelopmentProgrammeandcomposedofthreeindicesforlifeexpectancy,education,andGDP(Fig.35.15).Theserealitiesmakeitclearthatasocietyconcernedaboutequity,determinedtoextendagoodqualityoflifetothelargestpossiblenumberofitscitizensandhencewillingtochannelitsresourcesintotheprovisionofadequatediets,goodhealthcare,andbasicschoolingcouldguaranteedecentphysicalwell-beingwithanannualpercapitause(convertedwithtoday’sprevailingefciencies)ofaslittleas50GJ.Amoresatisfactorycombinationofinfantmortalitiesbelow20,femalelifeexpectanciesabove75years,andHDIabove0.8requiresannuallyabout60GJ.But,oncethephysicalqualityoflifereachesasatisfactorylevel,otherconcernsthatcontributetotheoverallwell-beingofpopulationsbecomeprominent: VaclavSmil Fig.35.16.PercapitaenergyuseandthePoliticalFreedomIndex.Pushingbeyond110GJpercapitahasnotbroughtmanyfundamentalquality-of-lifegains.Iwouldarguethatpushingbeyond200GJpercapitahasbeen,onthewhole,counterproductive.Theonlyunmistakableoutcomeisfurtherenvironmentaldegradation.Theseconsiderationsbecomeevenmoreintriguingoncetheserationallimitsonaverageenergyuseareconsideredtogetherwithpotentiallylargegainsfromfurtherimprovementsoftypicalenergy-conversionefciencies.Giventheannual1%–1.5%efciencygain(aratewellsupportedbyhistoricalexperience),withinagenerationtoday’slevelofusefulenergyservicescouldbesupportedwithinitialenergyinputs25%lower.Thismeansthat,in2020,agoodqualityoflifethatnowrequiresaround110GJpercapitacouldbesupportedwithprimaryinputsofjustaround80GJpercapita,aratethatisonlymarginallyhigherthantoday’sglobalmeanof75GJpercapita.TheUN’smediumvariantofitsglobalpopulationforecastsees25%morepeopleby2030comparedwiththepopulationin2005,whichmeansthatduringthenextgenerationwewouldneedtoincreaseglobalenergyusebyonly25%–30%inordertoprovideeveryoneofthe8.1billionpeopleintheyear2030withadecentqualityoflife.35.6ChoicesaheadTrulylong-rangeforecastsareimpossible,albeitincreasinglycommon.Twoprominentphysicists,MartinReesandStephenHawking,haverecentlyjoinedthecatastrophistschool. VaclavSmilRebuttalsoftheseobjectionsareequallyobvious.Tobeginwith,percapitaconsump-tionofaround75GJperyearshouldbeviewedasadesirablemodalvalueratherthanasanactualmeanwithtightdeviations,andonetobeachievedbyagradualprocessspanningatleastseveralgenerations.Moreimportantly,life-cycleassessmentsofprod-uctsandprocessesandstudiesinenvironmentaleconomicsshowthatagreatdealofcurrentenergyuseinafuentcountriesiswastedonenvironmentallydamagingactivi-tieswhoseeliminationcouldonlyimprove,ratherthanreduce,theoverallstandardofliving.Mostfundamentally–unlessonepositssuchimprobablesolutionsastheimminentavailabilityofinexpensivefusionorcommercialharnessingofanentirelynewsourceofenergy–thereisnoothermoreefcaciousalternative.Thebenetsofhighenergyusethatareenjoyedbyafuentcountries,thatisbylessthanone-sixthofhumanity150GJpercapita,cannotbeextendedtotherestoftheworldduringthenextoneortwogenerationsbecausefossilfuelscannotbeproducedatthatrateeveniftheirresourceswerenotanissue,and,inanycase,theenvironmentalconse-quencesofthisexpansionwouldbequiteunacceptable.Arenottheserealitiessuf-cientlycompellingtostartusthinkingaboutwhattoomanypeoplebelievetobeunthink-able,aboutapproachingtheglobalenergyproblemasanethicalchallenge,asamoralItssolutionwouldthenconsistofdeterminedmovestoendthehistoricquestforeverhigherenergythroughputs,toputinplacerationallimitsthatguaranteeadecentqualityoflifeforanincreasingproportionofhumanitywhilepreservingtheintegrityoftheonlybiosphereourspecieswilleverinhabit.Extractionandconversionoffossilfuelsremovedthekeylimitthathadhistoricallybeenimposedonenergyuxthroughhumansocietiesthroughtheinefcientuseofcurrentsolar-energyincome.Thisallowedtheafuentnationstopushthequestformaximizedenergythroughputsfarbeyondthelevelscompatiblewithtolerableglobalinequitiesand,becauseoftheinevitableby-productsofthecombustionoffossilfuel,alsobeyondthelevelscompatiblewiththelong-termintegrityofthebiosphere.Wehavethetechnicalandeconomicmeanstomovegraduallyawayfromthepursuitofmaximizedenergythroughputsandthusreverseperhapsthegreatestimperativeofhumanevolution.Themodalitiesofthisfundamentalevolutionaryshiftcannotbespeciedaprioriinanygrandioseglobalorintergovernmentalplan.Aswithanyultimatelysuccessfulevolutionarytrend,theywillhavetoemergefromanunruly,complex,andprotractedprocesswhoseprogresswillbemarkedbywrongchoices,cul-de-sacs,andunproductiveerrors.Themostimportantrststepistoagreethatanever-risingenergyandmaterialthroughputisnotaviableoptiononaplanetthathasanaturallylimitedcapacitytoabsorbtheenvironmentalby-productsofthisratchetingprocess.ToinvertLotka’sdictum,wemustsooperateastostabilizethetotalmassoftheorganicsystem,tolimittherateofcirculationofmatterthroughit,andtoleaveanunutilizedresidueofmatterandavailableenergyinordertoensuretheintegrityofthebiosphere. Science,energy,ethics,andcivilizationAcknowledgmentsIdeas,technicaldetails,andstatisticsinthischapteraredrawnfromthesourcescitedinthelistbelow,aswellasfromtheReviewofWorldEnergy(2006)publishedbyBritishPetroleum(http://www.bp.com/worldenergy).ReferencesBureauofTransportationStatistics(BTS)(2007).NationalTransportationStatistics2007(Washington:BTS).Imhoff,M.L.,Bounoua,L.,Ricketts,T.,etal.(2004).Globalpatternsinhumanconsumptionofnetprimaryproduction.Nature,870–3.Jevons,S.(1865).TheCoalQuestion:AnInquiryConcerningtheProgressoftheNation,andtheProbableExhaustionofourCoalMines(London:Macmillan).Jochem,E.,Favrat,D.,Hungerbuhler,K.,etal.StepsTowardsa2000WattSociety–AWhitePaperonR&DofEnergy-efcientTechnologies(Zurich:ETHurichandnovatlantis).Lotka,A.(1922).Contributiontotheenergeticsofevolution.Proc.NatlAcad.Sci.USA,147–51.MillenniumEcosystemAssessment(2005).OurHumanPlanet(Washington:IslandRojstaczer,S.,Sterling,S.M.,andMoore,N.J.(2001).Humanappropriationofphotosynthesisproducts.,2549–51.Smil,V.(1994).EnergyinWorldHistory(Boulder:WestviewPress).Smil,V.(2002).EnrichingtheEarth(Cambridge:MITPress).Smil,V.(2003).EnergyattheCrossroads(Cambridge:MITPress).Smil,V.(2006).Transformingthe20(NewYork:OxfordUniversityPress).Smil,V.(2007).EnergyinNatureandSociety(Cambridge:MITPress).USEnergyInformationAdministration(EIA)(2001).2001ResidentialEnergyConsumptionSurvey(Washington:EIA).