Performance standard for tropical outdoors: A critique of current impasse and a proposal for way forward

2018·0.8 MB·English

by  Rohinton Emmanuel

UrbanClimate23(2018)250–259
ContentslistsavailableatScienceDirect
Urban Climate
journalhomepage:http://www.elsevier.com/locate/uclim
Performance standard for tropical outdoors:
A critique of current impasse and a proposal for
way forward
RohintonEmmanuel
GlasgowCaledonianUniversity,Glasgow,UK
a r t i c l e i n f o a b s t r a c t
Articlehistory: Climatechangewillbringmoreheatextremestothealreadywarm
Received31May2016 tropicalareasinAsia,AfricaandLatinAmerica.Theresultingsurgein
Receivedinrevisedform12December2016 coolingdemandwillonlymakethethermaldiscomfortintropicalcities
Accepted5January2017 evenworse.Thispaperpresentsevidencetotheapproachingaircondi-
tionedcoolingloaddelugeandshowswhytheairconditionedmanage-
mentofcoolingloadisparticularlyproblematicinthetropics.Itthen
Keywords: presentsthetechnical,institutionalandculturalchallengestopassive
Tropicalurbanclimate
climate-sensitivedesigninthetropicsandpositsthreeideasaspartof
Urbandesign
thewayforward:reformulationofthermalpleasureinthetropics,
Thermalcomfort
linkingthe‘in’andthe‘out’atneighbourhoodscaleandprovisionof
Coolingload
Urbanheatisland adaptiveopportunitiesvariedbyactivitypatterns.Researchapproaches
toadvancetheseideasarealsodiscussed.
©2017ElsevierB.V.Allrightsreserved.
1.Introduction
Unusual(N3standarddeviations[SD]abovethebaseclimateof1951–1980)andunprecedented(N5SD)
heatextremesareexpectedtobethenorminmuchofAsiaandAfricaintheneartermevenastheseregions
undergotransformationalsocialandeconomicchange(IPCC,2013).InSub-SaharanAfrica,unprecedented
heatextremesareprojectedoveranincreasingpercentageoflandareaasglobalwarmingintensifiesfrom
2to4°C,resultinginsignificantchangesinvegetativecoveranddroughtevents(Lottetal.,2013).InSouth-
eastAsia,heatextremesthatarevirtuallyabsentatpresentwillcovernearly60–70%oftotallandareainsum-
mer,evenundera2°Cglobalwarmingscenario;with4°Cglobalwarming,summermonthsthatintoday's
climatewouldbetermedunprecedentedwouldbethenewnormal,affectingnearly90%ofthelandarea
(Sillmannetal.,2013).InSouthAsia,thesituationisevenmoreextreme,irrespectiveoftheglobalemission
E-mailaddress:[email protected].
http://dx.doi.org/10.1016/j.uclim.2017.01.002
2212-0955/©2017ElsevierB.V.Allrightsreserved.
R.Emmanuel/UrbanClimate23(2018)250–259 251
paths(Sillmannetal.,2013;Kumaretal.,2010).Reductionincolddays(Yanetal.,2002),increaseinbothcold
andwarmtails(KleinTanketal.,2006),significantincreasesintheannualnumberofhotdaysandwarm
nights,decreasesincolddaysandcoldnights(Mantonetal.,2001;Griffithsetal.,2005)andincreasesin
warmextremesarealllikelyinmuchofAsiaandAfrica.
ThemostpopulouspartsofthesecontinentsarewithintheTropicalbelt(fromapproximately23oNto23oS
oftheequator).Consequently,tropicalcoolingload–muchofwhichiscurrentlylatentduetorelativelylow
(albeitrapidlyrising)levelsofeconomicdevelopment–islikelytobethedominantcategoryofglobalenergy
demand(IsaacandvanVuuren,2009).Inthecurrentparadigm,suchincreasesincoolingloadcouldonlybe
metbyairconditioningmoreandmorebuildings(DavisandGertler,2015),exacerbatingthewarmingprob-
lem.Atthesametime,deeptechnologicaldevelopmentandefficiencyimprovementsincoolingsystemsare
yettobeachieved.
Tomakemattersworse,contemporaryculturalpracticesandattitudeslimitadaptivepossibilitiesto
warmertemperaturesastheimprovingsocioeconomicconditionsleadto‘thermalindulgence’(Hitchings
andLee,2008;Hanetal.,2009;Indraganti,2010a;Karyonoetal.,2015).Thereisevidencethatlong-termex-
posuretoairconditionedenvironmentmayevenhamperpeople'sphysiologicalacclimatizationandweaken
thermaladaptability(Yuetal.,2012).Greateruseofairconditioningleadstoacycleofculturaldependency,
andbreakingitappearsenormouslydifficult(ChangandWinter,2015).Onelikelyoutcomeofthesedevelop-
mentsisanunrealisticthermalcomfortexpectationinthetropicsthatisindirectconflictwiththe‘global
good’oflow/zerocarboneconomy.Acompromisehastobereachedbetweensocietalprioritiesandpersonal
desirestoensurelowestenergyexpenditurewithoutconfiningtropicaldwellerstoan‘inferior’thermal
comfort.
Thispaperpresentsevidencetotheapproachingairconditionedcoolingloaddelugeinlightofthechang-
ingclimatemadeworsebyurbanization,critiquesthecurrentinabilitytoeffectivelydealwiththeproblem
andproposesanewwayofmanagingthecoolingloaddelugeby‘climate-sensitivecommons.’TheBackground
sectionpresentssixreasonswhythecoolingloadprobleminthetropicsisuniqueandinneedofnewthinking.
Inlightofthese,threeideasareputforwardforfutureurbanclimate-sensitivedesigninthetopics.Finally,five
researchandknowledgetransferneedsarepositedasnecessarytorealisethesedesignideas.
2.Background
Muchoftheclimatechangerisksinthetropicsareconcentratedinurbanareas.Theseincluderisingsea
levelsandstormsurges,heatstress,extremeprecipitation,inlandandcoastalflooding,landslides,drought,
increasedaridity,waterscarcityandairpollution(Revietal.,2014).Giventhecurrentlevelofurbangrowth
andtheconcentrationofpopulationsinvolved,climatechangewillinteractwiththeurbanrisksinavarietyof
ways,someofwhichwillexacerbatethelevelofclimaterisk(IPCC,2013).Furthermore,therearehealthin-
equalities,especiallyindevelopingcitiesthatarefurtherexacerbatedbyurbanwarming(cf.Campbell-
LendrumandCorvalán,2007).
However,researchontheaugmentationofclimatechangeeffectsbylocalurbanwarming(characterised
byurbanheatislands)remainsweak.Initially,eventheIntergovernmentalPanelonClimateChange(IPCC)
overlookedtheroleofcitiesbothasaforcingfactoraswellasakeystakeholderinmanagingclimatechange
(HebbertandJankovic,2013).Additionally,translatingfutureclimatechangeprojectionsatfinerspatialscales
relevanttocitiestypicallyusestatisticaldownscalingtechniquestoglobalclimatemodelswithoutmodelling
theurbanareasthemselves(Lemonsuetal.,2013).Furthermore,thepracticalimplementationofthelimited
urbanwarmingknowledgeisrare.
Butthingsarechanging:urbanheatislandmitigationisexplicitlymentionedinIPCCAR5WorkingGroup3
Chapter9(Luconetal.,2014).Explicitconnectionsbetweenclimatechangeandactionincitiesisincreasingly
beingmade(forexample,Rosenzweigetal.,2015).Toolsandstrategiestoevaluatetheeffectivenessofheat
islandmitigationmeasures,suchastheComprehensiveAssessmentSystemforBuildingEnvironmental
Efficiency–HeatIslandTool(CASBEE-HI-http://www.ibec.or.jp/CASBEE/english/overviewE.htm)have
beenproposed.However,theameliorationoftheheatislandeffectintheurbantropicsisparticularly
weak.Ontheonehand,knowledgeoftropicalheatislandsremainspatchyandnumericallyweak
(cf.Hungetal.,2006;Roth,2007).Ontheother,theproliferationofstrategiesfocusingonheating-
onlyclimates(orthedual-modeheating-and-coolingloadclimates)doesnotreadilytranslateto
cooling-onlyregions.
252 R.Emmanuel/UrbanClimate23(2018)250–259
2.1.Uniquenessofcoolingload
Thetaskofcoolingisverydifferentfromtheactofheatingduetophysical,socialandeconomicreasons.A
keydifferencebetweenheatingandcoolingisintherespectiveloadstructures.Coolingrequiresthetackling
oftheincreasesinboththesensibleaswellasthelatentloads(Kalvelageetal.,2014).Inthehumidtropics,
thiswouldtranslatetodehumidificationandcooling,doingbothofwhichwithoutover-compensatingfor
oneortheotherisextremelychallenging(Sekhar,2016).
Second,increaseduseofairconditioninginawarmingworldwillonlymaketheurbansituationworse.
Whileontheonehandtemperaturerisewouldleadtogreateruseofairconditioners(e.g.forevery1°C
riseambienttemperaturerise,theelectricityconsumptioninHongKongwasestimatedtoincreaseby9.2%,
3.0%,and2.4%indomestic,commercialandindustrialsectors,respectively–Fungetal.,2006)arecent
studyinMalaysiafoundthatevery1°Cincrementinoutdoortemperaturewillcausea2%dropinthecoeffi-
cientofperformanceofsplit-typeairconditioners(YauandPean,2014).Thisisinsharpcontrasttoheatingin
urbanareas,where,wastedheattendstoreducetheheatingloadforsurroundingbuildings(Futcheretal.,
2013).Thecurrentincreaseintemperatureduetoairconditionerusewasestimatedtobe0.5°Cbutcould
beupto2°Ciftheairconditioneruseistodouble(deMuncketal.,2013:210).
Third,evenwhenrunonfossilfuels,heatingcouldbeprovidedbyavarietyoffuels(gas,oil,etc.)thathave
lowercarbonfootprintsthanelectricity(especiallycoal-firedelectricity)whichisthepredominantsourceof
powerformostairconditioners.Thus,evenasmallincreaseincoolingloadcouldvastlyinflateglobalcarbon
emissions.
Fourth,muchoftheglobalheatingdemandisalreadymanifestwhilemuchofthecoolingdemandisstill
latent.Ürge-Vorsatzetal.(2015)foundthatregionsdominatedbyheatingloadwillseereducedorstagnant
growthinenergyusewhilewarmregionsdominatedbycoolingloadwillseeexponentialincreaseincooling
loads(seeFig.1andTable1).Thiswillbefurtherexacerbatedbytrendswithincountrieswithheatingand
coolingdemand–forexample,USA(Kalvelageetal.,2014)whereheatingdemandisexpectedtodecrease
whilecoolingdemandwillsoar.Currentlyheatingloaddominatedcountriestoo,areexpectedtohavesignif-
icantcoolingloadsinthecomingdecades.
Fifth,coolingitselfispotentiallymoreharmfulfromaglobalwarmingperspectivethanheatinginthatthe
refrigerantsusedintheprocess(mostlyhydro-fluorocarbons–HFCs)havegreaterglobalwarmingpotential
thanCO .HFCs'contributiontoglobalwarming,muchofwhichisfromairconditioningandrefrigeration,is
2
expectedtobe9–19%(CO equivalentbasis)ofglobalCO emissionsin2050underbusiness-as-usualscenario
2 2
(Veldersetal.,2009).
Finally,whilethephysicsandthepracticalitiesaremorecomplexthanheating,cooling–especiallythe
mechanisedvariety–isalsohardertodivestof,givenitssocialconstruct.Thecomfortof‘coolth’isoften
seenasasignofprogress,initiallyasignofluxurybuteventually,thefulfilmentofdesire.Heatingdoesnot
havethisassociationwith‘luxury’sincewarmthwasalwaysseenasaprimordialneed(cf.Sivak,2009).
Theassociationbetween‘coolth’andluxuryorprogressisnotuniquetothetropics:thereisevidence(e.g.
Ackerman,2002)tosuchassociationintheUnitedStatesduringtheearlyyearsoftheintroductionofair
Fig.1.Incomevscoolingloadcomparison(Source:Emmanuel,2016).
R.Emmanuel/UrbanClimate23(2018)250–259 253
Table1
Trendsinglobalresidentialspaceheatingandcoolingdemand(kW/m2)(Source:Ürge-Vorsatzetal.,2015).
2010 2020 2030 2040 2050
PacificOECDa 126.1 122.4 119.1 116.0 113.4
NAmerica 147.5 138.4 131.0 124.9 119.7
WEurope 128.3 123.1 118.4 114.2 110.4
Central&EEurope 152.6 148.1 144.8 141.8 139.1
FormerSovietUnion 205.1 198.4 194.5 191.6 189.0
LatinAmerica 63.3 60.2 59.5 59.3 59.6
Sub-SaharanAfrica 56.2 53.4 52.9 53.0 53.4
MiddleEastandNAfrica 55.6 55.1 56.0 57.4 58.0
CentrallyPlannedAsiab 37.4 41.2 43.8 46.8 47.5
SouthAsia 60.1 77.1 85.0 89.2 88.2
OtherPacificAsiac 46.4 45.5 45.6 45.9 46.5
Note(seehttp://www.iiasa.ac.at/web/home/research/researchPrograms/Energy/MESSAGE-model-regions.en.htmlfornamingconven-
tionsofworld'sregions).
a Cambodia,China(incl.HongKong),Korea(DPR),Laos(PDR),Mongolia,Vietnam.
b SoutheastAsiaandthePacificIslandstates.
c Australia,Japan,NewZealand.
conditioners.However,whatisuniqueaboutthetropicalcoolingloadanditsassociationwithluxuryisthe
scaleofthecoolingchallengemadeallthemorepressingbytherapideconomicprogresscurrentlyunderway
intheregionandthesizeofthetropicalpopulationthatwilldemandgreatercoolingintheyearstocome.
2.2.Currentimpasseinclimate-sensitivedesigninthetropics
Inspiteofthechangestotropicalclimatebothatglobal/regionallevelaswellasatcitylevelthereislittle
evidencethatclimatesensitivedesignhasreceivedanygreaterattentionthanithadeverhad.Threebroad
categoriesofbarriersneedtobeovercometoenhancethereputationofpassiveclimate-sensitivedesign
andembeditintoeverydayurbanlife:technical,institutionalandcultural.
2.2.1.Technical
Climateswithclearseasonalityhavethepossibilitytocontroltheindoorsatbuildingenvelopelevel,bya
clearseparationofthe‘in’fromthe‘out.’However,giventherelativelysmalldeviationoftypicaloutdoortem-
peraturesfromthecomfortrange,tropicalbuildingenvelopesaremoreporous;the‘in’andthe‘out’areoften
indistinguishable.Butthiswouldonlyworkiftheoutdoorconditionsareclosetothecomfortrange.Thecrux
oftheproblemisthattropics(especiallytheurbantropics)havewarmedtoanextentthatpassive,building-
levelstrategiesthatbenefitfromporousbuildingenvelopes(suchascrossventilationandnighttimecooling)
areunabletoprovideadequatecomfortbythemselves.Suchpassive‘traditional’approachestoclimate-sen-
sitivedesignappearslesseffectiveunderachangingandextremeclimate(Nguyenetal.,2011)especiallyin
urbanareas(PozasandGonzález,2016;Rubio-Bellidoetal.,2015;FoudaziandM'Rithaa,2013).Inother
words,thepassiveclimate-sensitivedesignoptionsatthebuildinglevelareapproachingthetechnicallimits
oflowenergydesigninthetropics,asthebackgroundclimatecontinuestowarm.Weneedagreementonthe
‘what’(i.e.thescope)ofclimate-sensitivedesign.
2.2.2.Institutional/governanceissues
Equallyimportantly,the‘how’ofclimatesensitivedesign,too,needsattention.Urbandesign,unlikethe
designofindividualbuildings,concernsthatwhichbelongstoallandisthereforesubjecttothe‘tragedyof
thecommons’(Hardin,1968).Thepromotionofgoodurbandesignthereforeneedsstronginstitutionalun-
derpinning.Onitsown,climatesensitivedesignlacksthecloutandcapacitytograbandholdtheattention
ofkeydecisionmakers.Thisisespeciallythecaseintropicalcitieswheretheproblemofovercrowdingand
themoreimmediaterisksassociatedwithclimate-change(suchasflooding,coastalerosion,duststorms
anddrought)areevermorepressing.Overcrowdinginparticularleadstosmallerbuildingplotsizes,resulting
eversodiminishingabilitytocoolbuildingsduetothethermalinterferenceofneighbouringstructures.The
embedding of climatesensitivedesign into everyday planning decisions will be important to success.
254 R.Emmanuel/UrbanClimate23(2018)250–259
However,climate-sensitiveplanningisscale-dependentandneedstobelinkedtothebroaderurbansustain-
abilityagendassuchaspovertyalleviation,economicdevelopmentandurbanregeneration(Mills,2006;
Georgescuetal.,2015).
Furthermore,innovativeinstitutionalarrangementsareneededtolinkon-the-groundscientificexpertise
totheneedsandrequirementsoflocaldecision-makersatcitylevel(cf.Rosenzweigetal.,2010).Plannedeco-
cities(suchastheMarinaBayFinancialCentredistrictinSingapore-https://www.ura.gov.sg/uol/master-
plan/View-Master-Plan/master-plan-2014/master-plan.aspx)provideearlyexamplesofsuchinnovative
andintegratedinstitutionalarrangements.Additionally,thegovernancearrangementsincitiestooneedcon-
sideration:whowillchampionclimate-sensitivedesign?Whoseprioritiesaredominantinurbancontexts;
andwhataretheimplicationsofthistoclimatesensitivedesign?Finally,how‘autonomous’arecitiesin
beingabletocharttheirownadaptationdestiny?
2.2.3.Culturalbarriers
“Themostimportantpointisthateventhemosttradition-minded,nature-orientedorenvironmental-
ly-concernedfamilywouldhavedifficultylivinginamodernTrivandrum(capitalofhumidtropical
SouthernIndianStateofKerala)homewithoutair-conditioning.(Wilhite,2009,p.193)”
Perhapsthegreatestchallengetoclimate-sensitivedesigninthetropicsiscultural.Opennesstopassive
climatesensitivedesigndependsonthesocioeconomicstatus.Thosewhocanaffordtheenergyexpenditure
onairconditioningtendtobe‘thermallyindulgent’tothepointoflowtoleranceforthermaldispleasure
(Indraganti,2010a).ThisleadstowhatChangandWinter(2015)called‘Thermalmodernity.’Additionally,
culturalpracticesandpreferences/attitudesleadto“restrainedadaptiveopportunity”(Indraganti,2010b),
resultingfromthewayalternatechoicesarepresentedandmadepossible(Wilhite,2009).Examplesof
suchculturalpracticesandpreferencesincludethepracticeofairconditioningallpublicplaces(Hitchings
andLee,2008),increasedindoordwellingasclimatewarms(ZivinandNeidel,2014),enjoyingthecoolcom-
fortofexcessivelycooledshoppingmallsinIndiaandSingapore(Chua,2003)andwinterwearinSingaporeas
‘culturallyexpressiveformsofclothing’(HitchingsandLee,2008).
Astropicalcountriescontinuetheirmarchtowards‘middleincome’statusgreatercomfortisdemandedby
moreandmoreoftheircitizens.Animmersioningreatercomfort(i.e.greaterpleasure)appearstohyper-sen-
sitizehumanstoapointofinabilitytocopewithnaturalvariationsintemperature.Whiletheuseofaircon-
ditioningundoubtedlyleadsto‘superior’comfort(andhascometobeseenasasignof‘progress’inthetropics
–see,Lee,2009)italsodiminishesthecopingmechanismsoftropicaldwellers.
Climate-sensitivedesigncouldhelp,but,unfortunatelyithadhithertolargelyremainedaneliteprojectin
thetropics,wherethevastmajorityofbuildingscontinuetoberelegatedtotheintolerable-to-barely-passable
margins.Nocontextexistsfortheenjoymentofanotherwisepleasantclimatebyamajorityofcitizens.
3.Wheredowegofromhere?
Itissaidthatthermalcomfort(intemperateclimates)needstobe‘re-contextualised’inlightofclimate
change(Coleetal.,2008).Thisoftenmeansamoreinclusive,inhabitant-controlled,flexiblenotionofthermal
comfortthatallowsfor‘inhabitantagency’(Coleetal.,2008)butquestionsremainastoitsapplicabilityinthe
high-density,rapidlygrowingandgenerallyresource-poorurbantropics.Thenatureoftropicalthermalcom-
fort,especiallyinlightofchangingurbanclimate,isnotalwaysachievableevenwith‘inhabitantagency,’at
leastnotmostofthetime.Whatthereforemustwedointhetropics?
Creatingaclimate-sensitiveurbanrealmisastrongpossibilityinthetropicsthatwouldenablethe‘condi-
tioning’ofindividualbuildingseasier.Thusitisproposedthatthechangingtropicalclimate,especiallyinthe
citiescouldonlybemadecomfortable(andplacesforhumanthriving)byclimate-sensitizingtheurbanrealm.
Itisnotexpectedthatdoingsowilleliminatetheneedforairconditioning.Farfromit;climate-sensitiveurban
designisacrucialenablerofoutdoorliving,eveninthefaceofclimatechange.Thiscouldcreatethecondition
foralternatewaysofenhancingurbanqualityoflifewhileindividualbuildingsmayormaynotneedaddition-
alcoolth.
R.Emmanuel/UrbanClimate23(2018)250–259 255
Thisendeavoriswiderthanwhataplanningoranurbandesignremitwouldallow.Weneedanewwayof
being,whichhasimplicationstothewaytropicaldwellersperceiveclothing,furniture,foodandindeedtheir
bodies.Whilethisisfartoowideasubjecttobecoveredinthispaper,threeideasarepositedascentraltothe
achievementofthermalcomfortinthetropicsasastartingpointforclimate-sensitivedesign:
Reformulationofthermalpleasureinthetropics.
Linkingthe‘in’andthe‘out’atneighbourhoodscale.
Provisionofadaptiveopportunitiesvariedbyactivitypatterns.
3.1.Reformulationofthermalpleasureinthetropics
Thermalpleasureinahotenvironmentisverydifferenttothatinacoldenvironment:coolnessisonly
‘skindeep’(i.e.wefeelevaporativeandconvectivecoolingonthesurfaceoftheskin,asopposedtowarmth,
whichisinternal–cf.Heschong,1979).Itisalsoaboutcalmingthesensesinahighly-(almostover-)simu-
latedenvironmentwheredeepshade,vegetationandwaterindividuallyorcollectivelyplayaroleincreating
asereneandcalmingeffect.
Attheheartofthisformulationofthermalpleasureisanurbanasymmetricalthermalenvironmentdom-
inatedbycoolspotsthatenablesgreaterenjoymentoftheoutdoors–aformofspatialalliesthesia(Parkinson
anddeDear,2015),thusenablinglow-energycoolingintheindoors.Anurbanasymmetricalthermalenviron-
mentcouldbeachievedinanumberofdifferentways,allaimingtocreateclimatically‘cool’urbanpublic
spaces:
Partiallyshadedpathways.
Strategicallyplacedandadequatevegetationcover.
Watermisting(seeEmmanuel,2016forfurtherdetails).
3.2.Linkingthe‘in’and‘out’atneighbourhoodscale
Theachievementofthermalcomfortinthetropicsisaboutthe“integrationofmicroclimate,formandfab-
ricofthebuilding”(RajapakshaandHyde,2012).Airconditioningleadsto“hardeningofthephysicalandso-
cialboundariesbetweenhomeandsurroundings”(Wilhite,2009).Substantialimprovementinindoor
thermalcomfortispossibleonlyifeffortstodosobeginattheneighbourhoodscale(i.e.outsidethebuilding).
Examplesoflinkingthe‘in’andthe‘out’atneighbourhoodscaleinclude,arcadedstreetfrontswrapping
aroundallbuildinginanurbanblock,tree-linedbuildingfrontagethatactaporousintermediarybetween
the‘in’andthe‘out’andshadingoftheinterstitialspacesbyajuidiciouscombinationofthree-dimensional
geometryof buildings andtheirsolarorientation (asexemplifiedbythe‘shadowumbrella’concept–
Emmanuel,1993).Suchmanipulationofsettlementgeometry,streetorientationandexternalfactorssuch
asstreettreescreate‘environmentaldiversity’(SteaneandSteemers,2004)thatwouldbecentraltoachieving
thermalcomfortinthetropicsbyclimaticallylinkingtheinsideofbuildingswiththeoutside.
Thelinkingofthe‘in’andthe‘out’oughttoreflectthepurposeforwhichthermalcomfortstandardsare
beingpromulgated.Lenzunietal.(2009)suggestdifferentiationofthermalstandardsalongthefollowing:
thesubject'sthermalsensitivity,accuracyrequiredforcarryingoutthetaskandthepracticalityofthermal
control.Wesuggestafourth,thedifferencebetweentheindoorandtheoutdoorconditionsthatneedtobe
achieved.
3.3.Provisionofadaptiveopportunitiesvariedbyactivitypatterns
Giventheyear-roundpossibilitytousetropicaloutdoorsfordailyliving,urbanthermalcomfortgains
greaterimportanceintheovercrowdedtropicswhereroomoccupancyratesareunhealthy(cf.Correa,
1989).Acriticalneedistospecifyoutdoorthermalstandardsintermsofurbanactivitiesthatfacilitatecom-
fortablemovementintheoutdoor,leadingtohigherquality-of-life.
Suchextensiontothecomfortzonecouldbegreatlyfacilitatedbytheprovisionofadaptiveopportunities
thatareorganisedaroundactivitypatternsoftropicalurbanlife.Emmanuel(2005)suggestedfoursuchadap-
tiveopportunitiesorganisedaroundtropicalactivitypatterns(SeeFig.2):
256 R.Emmanuel/UrbanClimate23(2018)250–259
Fig.2.Conceptualsketchesoutlining(a)Gatheringplaces,(b)shoppingstreetsand(c)pedestrianpathsandnodesthatalsofacilitateeve-
ninglife(Source:Emmanuel,2005).
a. ShoppingStreets–createcanyon-likeshoppingstreets,wherethestreetitselfisnorth/southrunning,with
buildingsonthewestbeingslightlytallerthanthoseontheeast.Linebothfacadesofstreet-facingbuild-
ingswitharcades,soastoprovideadequateprotectionfromrainandsun.
b. GatheringPlaces–surroundurbanwaterbodieswithabuiltformedgedbyarcades.Locatepublicactivities
alongthearcade,overflowingintothecommons.Dissuadeallactivitiesthatdonotdirectlybenefitfrom
water'sedgefromlocatingonurbanwaterfronts.
c. Provisionsforeveninglife–Eveningsaretropics'winter(Rao,1981).Streetcornersareespeciallyattrac-
tivetobeincorporatedintotheeveninglife,particularlyiftheyintersectnortherlyandeasterlyorienta-
tion.
d. PedestrianPathsandNodes–Establishanetworkofpedestrianlinksindependentofcitystreetnetwork.
Pathswithincityblockscouldbetheprimarycarriersofcoolair(sayfromapond).Whereverthepedes-
trianpathcrossesthevehicularpath,establishaplacetopause.
4.Researchandknowledgetransferneeds
Beforetheabovethreearegivenconcreteurbanform,itisnecessarytoconductfurtherresearchonthe
tropicalurbanwarmingproblem.Thesepertainto“data,technicalandscientificneeds”(suchasrelative
meritsofshadevs.ventilationtotropicalthermalcomfort),“socio-physiologicalandhabitualneeds”(such
R.Emmanuel/UrbanClimate23(2018)250–259 257
asthermalcomfortintheoutdoors,performancestandardsfordifferentactivitypatterns)and“politicaland
institutionalneeds”(implementationandmonitoring,urbanclimate↔globalclimatefeedback):
4.1.Shadevsventilation
Thecoolingeffectofventilationinthetropicsisnowpartoftheconventionalwisdom.Whatisnotwell
acknowledgedarethethermalcomforteffectsofwindinawarmingcity.Thecombinedradiantcoolingeffect
ofshadetogetherwiththeconvectivecoolingofwindontropicalthermalsensationneedsfurthersystematic
study.Theseasonalityofwind(asaffectedbythemonsoons)inconjunctionwiththeannualvariationsin
temperatures(highscoincidingwithweakwindpatternsduetothepassageofintertropicalconvergence
zone)needstobereflectedinfieldstudies.Thesubstantialbodyofresearchonshade-orientedplanningin
hot,dryclimatesandtheknowledgeofwindinhot,humidclimatesneedtobebroughttogethertounder-
standthepracticalpossibilitiesofboth,inwayssimilartothatattemptedbyBalslevetal.(2015).
4.2.Thermalcomfortinoutdoorswithavarietyofmorphologies
Closelyrelatedtothisisthecollectionofempiricalevidencetotheeffectofavarietyofurbanmorphologies
onoutdoorcomfortintheurbantropics.Thiswouldbenefitfromastandardizationofmeasurementprotocols
foroutdoorcomfort(cf.Johanssonetal.,2014).AkeyrequirementistheaccurateestimationofMeanRadiant
Temperature(T )whichismorecriticalinawarm,humidcontextthaninacold,dryone.Integralradiation
MRT
measurementsandthecalculationofangularfactorsasproposedbyThorssonetal.,2007isneeded.Johansson
etal.(2014)provideacomprehensiveoverviewofthemanytechniquestomeasureT .
MRT
4.3.Performancestandardsbyactivitypatterns/landuse
Theabovetwoareasofresearchshouldleadtoperformancestandardsforoutdoorurbanspaces.Asdiscus-
sioninSection3,itwouldbeidealifthesecouldreflectthemanyactivitypatternsappropriatefortropicalcit-
iesandhighlightedinthediscussionsabove.
4.4.Neighbourhoodscaleimplementationandmonitoring
Ultimately,theproofofthepuddingisintheeating.Aconsiderablebodyofknowledgealreadyexistson
approachesbasedontropicalventilation(Ng,2016),shade(Lin,2016)andvegetation(Duarte,2016).Both
traditionalsettingsand‘newtowns’developedpostWWIIcouldberipeforempiricalmeasurementsofout-
doorthermalcomfortconditionsunderthesethreeapproachesinthetropics.
4.5.Urbanclimateameliorationandregionalclimatefeedback
Astropicalcitiesgrow(andturnintomegapolii)moredirectfeedbackbetweenurbanland-coverandre-
gionalandperhapsglobalclimatemaybeforeseen.Althoughcitiescurrentlyoccupyonlyatinyfractionof
globallandcoverthismaychangedramaticallyinthetropicssoastohavearegionalclimateimpact.Thecli-
matetransformationofPearlRiverDeltaisacaseinpoint(Wangetal.,2014).Itisnecessarytostudysuch
regionalfeedbacksingreaterdetail.However,thenotoriouslywickedproblemofreliablelanduse/land
coverdatainthetopicsneedtobetackledfirst.Inthisregard,currentinitiativessuchastheWorldUrbanDa-
tabaseandAccessPortaltools(WUDAPT,Seeetal.,2015)andlanduse/landcoverparameterizationschemes
suchasLocalClimateZone(LCZ,StewartandOke,2012)couldofferpromisingheadstart.WUDAPTisacom-
munity-driveninitiativeamassingdataonurbanformandfunctiontohelpcitiesworldwidetodeveloptheir
ownheat-adaptationplans.Thiscouldprovideastandardizedcharacterizationoftheworld'smajorcitiesand
detailedinputdataforurbanclimatemodels.ApplicationofaversionofLCZfordata-poortropicalcitieshas
beenrecentlydemonstrated(PereraandEmmanuel,2016).
258 R.Emmanuel/UrbanClimate23(2018)250–259
5.Concludingremarks
AmeliorationofUHIprovidesalocalnarrativewithinwhichstrategiesfortheenhancementofurbanqual-
ity-of-lifecanfindacceptanceandevenactivesupport.Apoliticaldifficultywithactionagainstglobalclimate
changeistheinabilitytoseeresultsinthehereandnow.Tacklingtheurbanclimatechangeoffersimmediate
andtangiblebenefitssincethenegativeconsequencesofhaphazardurbanizationisplaintosee.Thisisin-
creasinglybeingrecognisedininternationalefforts.Examplesincludegreaterfocusonurbanclimatebythe
WorldMeteorologicalOrganisation(suchasthe“WMOUrbanAgenda”–http://public.wmo.int/en/our-
mandate/focus-areas/urban-development-megacities/wmo-and-new-urban-agenda); World Health
Organisation's(WHO)greaterattentiontopublichealth–especiallyageinginthechangingclimate(http://
www.who.int/globalchange/en/), and UN-Habitat III's smart city and quality of life agenda (http://
unhabitat.org/wp-content/uploads/2015/04/Habitat-III-Issue-Paper-21_Smart-Cities-2.0.pdf).Rapidlygrow-
ingtropicalcitiesneedtoparticipateinsuchinternationaleffortstoenhancetheirlocalenvironmentalcondi-
tionsevenastheycontributetotheglobalclimatechangeadaptationagenda.Experiencegainedinsuch
endeavourscouldenabletropicalcitiestopositivelycontributetothetwo-wayknowledgetransfer(between
thedevelopedanddevelopingworlds)oflivinginawarmingworld.
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