About Global Warming and Greenhouse Gases

10 Pages·1992·0.24 MB·English

by  Ontario Ministry of the Environment

:
ENVIRONMENT
ENVIRONNEMENT
Environment
WINTER1992 Environnen'ient HIVER1992
ABOUT GLOBAL LE RECHAUFFEMENT DU
WARMING AND GLOBE ET LES GAZ DE
GREENHOUSE GASES SERRE
THEGREENHOUSEEFFECT&GLOBAL L'EFFETDESERREETLERECHAUFFEMENTDU
WARMING GLOBE
Thegreenhouseeffectisoftenconfusedwithglobal Oncontendsouventeffetdeserreetr6chauffement
wanning. Whilethetwoarecloselyrelated,theyare dugk>be. Bienquecesdeuxph^nomdnessoient
notthesamething. apparent^s, lissonttoutefoisdistincts.
Thegreenhouseeffectisthenaturalprocessthat L'effetdeserreestleprocessusnaturelquipermetk
heatstheearth'ssurface,therebysupportinglifeon laterredeconserversachaleuretdepermettrela
earth. Heatfromthesunistrappednexttotheearth vie. Lachaleurdusoleilestemprisonn^epr^sdela
bygasesintheatmosphere. Thesearecalled surfacedelaten'epardesgazatmosph^riques. Ces
greenhousegases. Thegreenhouseeffectallows gazsontappel^sgazdeserre. L'effetdesen'e
someheattoescapeintospacebuttrapsenoughto permetkunecertainequantitydechaleurde
keeptheearthwarm. s'tehapper, maisenretientsuffisammentpourgarder
lasurfaceauchaud.
Globalwarmingisbelievedtobetheresultofhuman
activKies,suchasindustrialemissionsand Selonlesexperts,ler^hauffementduglobeestle
transportationemissions,impactingonthenatural rdsuHatdeI'activit^humaine,tellequelesAmissions
process. Thesecauseanincreasedamountof industriellesetcellesdesvdhiculeskmoteur,quiont
greenhousegasestobuildupintheatnrx)sphere uneincidencesurlesprocessusnaturals. Ces
beyondthenatural,lifesustaining,balance. Asa AmissionssontkI'originedeI'augmentationdela
result, moreheatmaybetrappednexttotheearth, quantitydegazdeserredansI'atmosphdre, au-delei
causingitgraduallytogetwarmer. desconcentrationsnaturellesquiassurentI'^quilibre
dcok^gique. Cons6quemment,uneplusgrande
THEGREENHOUSEGASES quantitydechaleursetrouveemprisonndekla
surfacedusol,cequientrafneunrdchauffementk
Thekeygreenhousegasesincreasingduetohuman I'tehelledelaplandte.
activityare: _^_
LESGAZDESERRE
• Cartjondioxide(00^)isthemostpredominant
greenhousegas. Itisincreasingintheatmosphere Lesprincipauxgazdeserredontlacpncentration
principallythroughthetxjmingoffossilfuelsand augmenteenraisondeI'activitdhumainesontles
tropicaldeforestation. Itsestimatedcontributionto suivants
gk)balwarmingis55%.
• Ledioxydedecart)one(CO^)estleplusabondant.
• Methane(CHJisreleasedfromricepaddies, L'augmentationdesaconcentrationdans
entericfermentation(intestinalgases,particularly I'atmosph^reestengrandepartieduekla
fromfarmanimals),gasleakagefromlandfillsand combustiondecombustiblesfossilesatau
theproductionanduseofnaturalgas. Methane's d6boisementdesforetstropicales. Lacontribution
concentrationhasdoubledinthepast200to300 decegazau r6chauffementduglobeestdeI'ordre
years. Itsestimatedcontributiontoglobalwarming de55%.
is15%.
• Lemethane(CHJprovientdesrizi§res,dela
• Nitrousoxide(Nj,0)canbeformedinthe fermentationent6rique(gaz intestinaux,
combustionofbiomass(vegetation)andfossil particuli6rementdesanimauxdeferme),des
fuels,butitsprincipalsourcesfromhumanactivity Emanationsdeslieuxd'enfouissementetdela
areprobablynitrogenfertilizersand nylon productionetdeI'utilisationdegaznaturel. La
manufacturinginOntario. Nitrousoxide's concentrationdemdthanedansI'atmosphdrea
estimatedcontributiontoglobalwarmingis6%. doubleaucoursdes200k300demi^resann^es.
Lacontributiondecegaz au r6chauffementdu
• Chlorofluorocartxjns(CFCs)andtheirsubstitutes globeestdeI'ordrede 15%.
(HCFCs)arepresentintheatmosphereat
extremelylowconcentrations, butareconsiderably • L'oxydenitreux (N^O) peutseformertorsdela
morepowerfulasaglobalwarminggasthan combustiondelabiomasse(v6g6taux)etdes
carbondioxide(Intergovernmental Panelon combustiblesfossiles, maisenOntario, sa
ClimateChange[IPCC]estimatesupto7300xover principalesourced'originehumaineestI'utilisation
100years). CFCsareusedas refrigerants,as d'engraisazoteset lafabricationdenylon. La
foamblowersandascleaningsolvents. Their contributiondecegazaur6chauffementduglobe
estimatedcontributiontoglobalwarmingis24%. estde6%.
CFCsalsodepletethestratosphericozonelayer • Leschlorofluorocartxjnes(CFC)etleurssubstituts
whichprotectsusfromtheharmfulultraviolet rays (HCFC)sontpresentsentr6spetitesquantit6s
ofthesun. dansI'atmosph^re, maiscontribuentbeaucoup
plusqueledioxydedecarboneau r^chauffement
• Ozone(O3) isalsoagreenhousegas, aswellasa duglobe. LeGroupeintergouvernementalde
pollutantintheloweratmosphere(troposphere). I'Evolutionduclimatestimequ'aucoursdes 100
Ozonemayplayanimportantroleinglobal derni6resann6es, ilsontcontribu67300foisplus
warming, howeveradditionalinformationonits queleCO^aur6chauffementduglobe. LesCFC
relativeatmosphericroleisrequiredtodetermine sontutilisesdanslesfluidesfrigorigdnes, les
itscontributiontoglobalwarming. agentsgonflantsetlesproduitsdenettoyage. La
contributiondesCFCau r6chauffementduglobe
GLOBALWARMING'SRISETOPROMINENCE estdeI'ordrede24%.
TheChangingAtmosphere: ImplicationsforGlobal LesCFCsontaussiresponsablesdela
Security,"wasaninternationalconferenceheldin deteriorationdelacouched'ozonestratosph6rique
Torontoin 1988. This,coupledwithrecordhigh quinousprotegecontreleseffetsn6fastesdes
temperaturesthatsummer,broughttheprospectof rayonsultravioletssolaires.
globalwarmingtotheforefrontofpublicattention.
• L'ozone(O3)estungazdeserreetunpolluantde
Scientistsatthisconferenceconcludedthat labasseatmosphere(troposphere). IIjoueraitun
greenhousegasesintheglobalatmospherewere r6leimportantdansler6chauffementduglobe. II
primarilybeingincreasedbyhumanactivitiesandthat nousfaudracependantobtenirdesdonnees
theultimateconsequenceofthisoccurrencecouldbe additionnellespouretablirdefagonprecisedans
secondonlytonuclearwar. quellemesureilcontribue^cephenomene.
TheIPCC, sponsoredjointlybytheWorld LE R^CHAUFFEMENTDU GLOBEA LAUNEDE
MeteorologicalOrganizationandtheUnitedNations L'ACTUALITfe
Environmental Program, madeseveralkey
determinationsaboutthisphenomenon. Itconfirmed En 1988,setenaitkTorontouneconference
globalwarming;forecasta2.5°C riseinglobal mondialeintituieeL'Atmosphereenevolution :
temperaturewithadoublingofcarbondioxide;and implicationspourlasecuriteduglobe. Cet
underscoredareasofuncertaintysuchassources evenementainsiquelavaguedechaleursans
andsinks (reservoirs, suchasoceans,that hold pr6c6dentquias6vidans lavilleaucoursdu m§me
greenhousegases),clouds,oceansandpolarice 6t6ontcontribu6^fairedu r6chauffementduglobe
sheets. TheIPCC haspredictedarateofglobal unedesgrandespreoccupationsdeI'heure.
meantemperatureincreaseofabout0.3°Cper
decade,or 1°Cabovethepresentvalue,by2025, Lesscientifiquespresents^cetteconferenceont
and3°Cbeforetheendofthenextcentury. Thisis determinequeI'augmentationdelaconcentrationdes
greaterthanthatseenoverthepast 160,000years. gazdeserredansI'atmosphereestattribuableen
grandepartieeiI'activitehumaine, etqueles
Whengreenhousegasesreachaconcentrationof consequencesdecettetendancepourraient§tre
doubletheamountofcartx)ndioxidepresentbefore presqueaussidevastatricesqu'uneguerrenucieaire.
theindustrial revolution, averagetemperatureriseis
expectedtobebetween 1.5-4.5°. This"doubling"is LeGroupeintergouvernementalderevolutiondu
expectedtooccursometimearoundthemiddleofthe climat,parraineparI'Organisationm6t6orologique
nextcentury. mondiateetleProgrammedesNationsUniespour
I'environnement,estparvenu^plusieursconclusions
THE EFFECTSOFGLOBALWARMING encequiatraitaurechauffementduglobe. IIa
confirmelatendanceau rechauffement,predisant
InCanada,itiseasytogettheimpressionthatglobal uneaugmentationglobaledelatemperaturede
warmingwillsimplymeanmorewarmweatherto 2,5°C, silesemissionsdedioxydedecarbone
enjoy. Howeverscientistsagreethatthereare doublaient, etasouligneI'importancedesvariables,
seriousandsevereimplicationsofglobalwarming. commelessourcesetlesreservoirs,tels lesoceans,
quiemprisonnentlesgazdeserre, lesnuagesetles
Seriouseffectsareexpectedbothgloballyandat nappesdeglacepolaire. LeGroupeapreditque
home: I'augmentationdelatemperaturemoyenneduglobe
seproduiraitauxtauxd'environ0,3°Cpardecennie,
• Sealevelrise: oceanlevelswill riseduetothermal soitde1 °Cd'ici2025et3°Cavantlafindu siecle
expansionandthemeltingofland-basedice. prochain. LaTerren'apasconnu unrechauffement
Coastalcommunitiesmayexperiencetheproblem aussimarqueaucoursdes 160000dernieres
ofcoastalerosion, lossofwetlandandsaltwater annees.
intrusionintofreshwatersystems. Coastal
communitiesandsmallislandnationswillalsobe Lorsquelaconcentrationdesgazdeserreatteindra
affectedorrendereduninhabitable,dependingon ledoubledesquantitesdedioxydedecarbonequi
therateandextentofsearise. Human impacts etaientpresentesdansI'atmosphereavantla
alreadyincludelargeexpenditurestoconstruct revolutionindustrielle,ons'attendkcequela
dykesandmayincreaseenvironmentalrefugees. temperaturemoyenneduglobes'eievede 1,5^
4,5°C. Cedoublementestprevupourlemilieudu
• Changesinprecipitationpatterns: increasesor siecleprochain.
decreasesinprecipitationinsomeareasmay
increasedroughtsorflooding. IncentralNorth LESEFFETSDU RECHAUFFEMENTDU GLOBE
America,decreasesinprecipitationarepredicted
withincreasingtemperatures. Watersuppliesfor AuCanada, I'impressiongeneraleestquele
humanconsumption,shippingandhydraulicpower rechauffement nouspermettradeprofiterde
maybeadverselyaffectedbytemperaturerise. temperaturespluscl6mentes. Cen'estcependant
pasI'avisdesscientifiquesquis'entendentpourdire
• SoilerosioninNorthernOntariocoulddevelopinto quelerechauffementauradesrepercussionsgraves
amoreseriousagriculturalandenvironmental surI'environnement.
problem.
Ceseffetsaurontuneincidenceglobaleet locale :
• Decreasesinplantandanimalproductivity, inboth
naturalandagriculturalsystems, mayoccur. Since • Lahausfieduniveaudesoceans :I'expansion
theeffectsofclimatewarmingwouldberelatively thermiqueetlafontedesglacesdeterreferont
greaterinnorthernpartsofOntario, northerncrop monterleniveaudesoceans. Lesregionsc6tieres
choicesarelikelytochange. Forestrymayalsobe pourraientStresujettesSI'erosion,^lapertedes
seriouslyaffected. ten'eshumidesetkI'infiltrationd'eausaieedans
• Migrationofpests: locusts, aphidsandmoths lescoursd'eaudouce. Lesregionsc6ti6resetles
becomemoreactiveinwarmertemperaturesand Tiespourraientaussietretouch6esou rendues
maymigratenorth. inhabitables,selonlavitesseetI'ampleurdela
haussedu niveaudesoc6ans. Dessommes
• Impactsonhumanhealth,suchascardiovascular, considerablesontd^j^§teinvestiesdansla
cerebrovascularandrespiratorydiseases, may constnjctiondediguespourcontrerleseffetsdu
increase. Theeffectsarelikelytobefeltbythe rdchauffement. Lenombreder6fugi6s
elderly,chronicallyillandtheveryyoung. Vector- environnementauxrisqued'augmenter.
bornediseases, includingmalaria,schistosomiasis
and leishmaniasis, areexpectedtoshiftnorth. • Lechangementdelaconfigurationdes
precipitations :I'augmentationou ladiminutiondes
HOWCANGLOBALWARMING BESTOPPED? precipitationsdanscertainesregionspeuvent
entrainerdesinondationsetdesp6riodesde
Thefirststepistostabilizeglobalgreenhousegas s6cheresse. Dansles regionscentralesde
emissions. Beyondthis, IPCCandotherscientists, I'Amehquedu Nord,onpr6voitunediminutiondes
havecalculatedthecutsinemissionsrequiredto precipitationsetuneaugmentationdes
stabilizetheconcentrationsofgreenhousegasesat temperatures. Lesreservesd'eaupotable, le
theircurrentatmosphericlevels: transportmaritimeetlaproductiond'energie
hydrauliquerisquentdesouffrir.
Carbondioxide: greaterthan60%reduction
• L'6rosiondessolsdanslenordderOntario
Methane: 15-20%reduction pourraitdevenirunprobiemeagricoleet
Nitrousoxide: 70-80%reduction environnementaldeplusenplusinquietant.
CFC-11: 70-75%reduction
CFC-12: 40-50%reduction • Unediminutiondelaproductivitev6getaleet
animate, autanten milieu agricolequ'enmilieu
HCFC-22: 40-50%reduction naturel, est^pr6voir. Commeleseffetsdu
rechauffementserontprobablementplusmarqu6s
Asafirststep,Canadaandanumberofother dansles regionsdu norddeI'Ontario, lavari6t6
industrializedcountries havecommittedtothe desculturesviabless'entrouveramodifi6e. Les
establishmentofnationalstrategiestostabilize activitesdeforesterierisquentaussid'etre
carbondioxideandgreenhousegasemissionsat durementtouchees.
1990levelsbytheyear2000.
In 1989, OntariobecamethefirstNorthAmerican • Lacarimdiigernast,iopnucde'rinosnescteetspaipnidlelsoinrsabdleesnu:iIt'aactuigvimteendtees
jurisdiction, sincethesigningoftheMontreal aveclatemperature. Aussi, cesderniersauront
Protocol,tobanthemanufactureandimportof tendance^migrerverslenord.
productsusingCFCsaspropellantsinaerosolsprays
orasblowingagentsinfoampackaging. TheOntario • L'incidencedesmaladiescardiovasculaires,
governmentisalsolookingatotherwaystoreduce cerebrovasculaireset respiratoiresrisqued'etre
itscontributiontoglobalwarmingbypromoting plus marqueechezleshumains,surtoutchezles
energyefficiencyandthroughan interministerial personnesSgees, lesmaladeschroniquesetles
workinggrouponglobalwarming. jeunesenfants. Les maladies^transmission
HOWCAN IHELP? vlaeclteoriisehlmlae,nicosoem,mreislqauemnatladreias,elarespcahnidsrteosdoamnisasleeset
regionsdu nord.
Thereareseveralthingsthatyoucandotohelp
reducegreenhousegasemissions: COMMENTPEUT-ON METTREUNTERMEAU
RECHAUFFEMENTDU GLOBE?
• Conserveenergy: turnofflights,hotwaderand
applianceswhen notinuse;buyenergyefficient IIfaudraitd'abordfaireensortequelaconcentration
goods;walk,cycle,orusepublictransitinsteadof desgazdesenredansI'atmospherecesse
drivingwheneverpossible; ifyoudodrive,keep d'augmenter. LeGroupeintergouvernementalde
yourcarwelltunedandturnyourengineoffrather revolutionduclimatetd'autresspecialistesont
thanlettingit idle;carpoolwheneverpossible. calcuiequ'ilfaudrareduirelesemissionsdegazde
• Switchyourenergysource: usenaturalgas serrecommesuitpourqueleurconcentrationdans
insteadofoilifavailable;electricalwaterheating I'atmosphdredemeureauxniveauxactuels :
andspaceheatershelpaswell;addrenewable
sourcessuchassolarwaterheaters. Dioxydedecarbone:r6ductiondeplusde60%
• CEaNllEtRhGeYM1inifsotrrmyoorfeEnideeragsyoInnfsolaivnienagte1n-e8r0g0y-. OM6xtyhdaenneit:rreeudxu:ctrieodnucdteio1n5d^e2700%k80%
CFC 11 : reductionde70^75%
• Reduce, Reuseand Recycle: employthe3Rsof CFC 12 : r6ductionde40^50%
wastemanagementandhelpsaveenergyby HCFC22 r6ductionde40k50%
reducingtheneedtomanufactureproductsfrom :
scratchandbyalleviatingstressonmethane LeCanadaetuncertainnombred'autrespays
producinglandfillsites. industrialistsontdoned^id^d'^iaborerdes
strat6giesnationalesvisantSramener,d'ici I'an2000,
• Useyourpowerasaconsumer: buyenergy les6missionsdedioxydedecarboneetdesautres
efficient, environmentallyfriendlygoodsthatare gazdeserreauxniveauxde 1990.
reusable,recyclable, madefromrecycled
mHaFteCriaanlsd,HaCreFCnotfroeev.erR-peamcekmabgeerd,aynoduacreanCFalCs,o AEmn61r9i8q9u,erdOuntNaorriod6^tamiettltarpereenmiveirgeuecuor,mpaeptre6nscleaen
requestthatsuchitemsbestockedifnotreadily signaturedu ProtocoledeMontreal,une
available. r6glementation interdisantlafabricationet
I'importationdeproduitscontenantdesCFC, comme
• Planttrees: treesabsorbandstorecartxsndioxide. lesagentspropulseursdanslesaerosolsetles
Inaddition, ifproperlyplaced, treescannaturally agentsgonflantsdanslamoussed'emballage. Le
reduceheatingandcoolingneedsbysheltering gouvernementdeI'Ontariosepencheaussi sur
homesfromwindandsun. d'autresfagonsder6duiresacontribution au
rechauffementduglobeen mettantsurpieddes
• Joinanenvironmentalinterestgroup. campagnesdesensibilisationkI'utilisation
FOR MOREINFORMATION 6conomiqueder6nergieetenconstituantungroupe
detravailintemninist^rielsurlerechauffementdu
globe.
EnvironmentOntariohasseveralinfomnationpieces
onthesubjectofairpollutionandothertopics. These COMMENTPUIS^JECONTRIBUER?
areavailablethroughtheministry's Public Information
Centrelocatedat 135St.ClairAve.W.,Toronto, Vouspouvezcontribuer^r6duirelesAmissionsde
OonpteanriMoonMd5aVy1tPh5r.ougThheFrPiudbaly,icfrInofmo9rm:a0t0ioan.mC.entreis gazdeserredeplusieursfagons :
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quevotrev6hiculesorttoujoursenbon6tatde
marcheetcoupezlecontactau lieudelaisser
tournerlemoteurinutilement;etpratiquezle
covoiturageleplussouventpossible.
• Changezdesourced'6nergie :utilisezlegaz
naturelplutdtqueI'huile, sipossible;I'emploide
chauffe-eau 6lectriquesetderadiateursportatifs
estaussirecommand6. Essayezlessources
d'6nergierenouvelable,commeleschauffe-eau
solaires.
• CommuniquezavecleministdredeI'^nergiede
rOntarioau 1-800-ENERGY1 pourobtenirdeplus
amplesrenseignementssurlaconservationde
r6nergie.
• RMuisez,rdutiiisezetrecyclez :lapratiquedes3
« R » contribued6conomiserI'^nergieen
rMuisantlan^essitddefabriquerdenouveaux
produitsetenall^eantlefardeaudeslieux
d'enfouissementquilib^rentdu methane.
• Utilisezr^nergiedefaQonrationnelle :achetezdes
produits6cosympathiquesau rendementefficace
quisontrdutilisables, recyclables,fabriqu^skpartir
dematidresrecycldes,nonsuremball^setne
contenantpasdeCFC,deHFCnideHCFC.
N'oubliezpasquevouspouvezdemanderaux
d^aillantsdeseprocurerdetelsproduitss'ilsne
lesoffrentpasd^j^.
• Plantezdesarbres :lesarbresabsorbentet
emmagasinentledioxydedecarbone. Deplus, lis
peuventcontribuerkr6duirevosbesoinsen
chauffageetencliniatisations'ilssontplaodsde
fagon^prot^ervotredemeurecontreleventetle
soleil.
• Joignez-vouskungroupededefensede
I'environnement.
RENSEIGNEMENTSADDITIONNELS
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d'informationsurlapollutiondeI'airetsurd'autres
sujets. Vouspouvezvous lesprocurerauCentre
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