ChCh1414

BIOL101BIOL101

• MaldivesIslandsintheIndianOcean

• Paradise

• Couldbesubmergedbyrisingseas

• Accompanyingglobalclimatechange

• 80%oflandlieslessthan1m(39in)abovesealevel

• Higherseaswillfloodareasandcontaminatedrinkingwater

• Governmenthasalreadyevacuatedresidents

• Fromthelowest‐lyingislands

• OtherislandnaNonsandmainlandcoastalareas

• Willfacesimilarchallenges

• Climate

• Anarea’slong‐termatmosphericcondiNons

• Temperature,moisturecontent,wind,precipitaNon,etc.

• Influenceseverythingaroundus

• Weather

• CondiNonsatlocalizedsitesoverhoursordays

• Globalclimatechange

• DescribestrendsandvariaNonsinEarth’sclimate

• Temperature,precipitaNon,stormfrequency

• Globalwarming

• AnincreaseinEarth’saveragetemperature

• Earth’sclimatehasvariednaturallythroughNme

• RapidclimaNcchangeshappeningnowduetohumanacNvity

• Fossilfuels,combusNon,anddeforestaNon

• Atanunprecedentedrate

• Threefactorsexertmoreinfluenceonclimatethanallothers:

• Thesun—withoutit,theEarthwouldbedarkandfrozen

• Theatmosphere—withoutit,theEarth’stemperaturewouldbemuchcolder

• Theoceans—storeandtransportheatandmoisture

• AsEarth’ssurfaceabsorbssolarradiaNon

• Thesurfaceincreasesintemperature

• andemitsinfraredradiaNon

• Greenhousegases

• AtmosphericgasesthatabsorbinfraredradiaNon

• Watervapor,ozone,carbondioxide,nitrousoxide,methane,chlorofluorocarbons(CFCs)

• Greenhousegasesdiffer

• Intheirabilitytowarmthetroposphereandsurface

• A\erabsorbingradiaNon

• Greenhousegasesre‐emitinfraredenergy

• Someenergyislosttospace

• Greenhouseeffect

• Someenergytravelsbackdownward

• Warmingtheatmosphereandplanet’ssurface

• Globalwarmingpoten7al

• RelaNveabilityofonemoleculeofagivengreenhousegastocontributetowarming

• ExpressedinrelaNontocarbondioxide(potenNal=1)

• Hydrochlorofluorocarbonsare12,000Nmesaspotentascarbondioxide.

• Notthemostpotentgreenhousegas

• Butitisextremelyabundant

• Themajorcontributortoglobalwarming

• EmissionsofgreenhousegasesfromhumanacNviNes

• Consistmostlyofcarbondioxide

The atmosphere’s concentrationsof CO2 are now at their highestlevel in over 800,000 years.

• Usingfossilfuelsinhomes,factories,andautomobiles

• Transferslargeamountsofcarbondioxide

• Fromlithosphericreservoirsintotheatmosphere

• ThemainreasonatmosphericcarbondioxideconcentraNonshaveincreasedsodramaNcally

• DeforestaNonhascontributedtorisingatmosphericCO2

• ForestsserveassinksforrecentlyacNvecarbon

• Theirremovalreducesthebiosphere’sabilitytoabsorbcarbondioxidefromtheatmosphere

• Methane

• Fossilfueldeposits,livestock,landfills,andcropssuchasrice

• Nitrousoxide

• Feedlots,chemicalmanufacturingplants,autoemissions,andsyntheNcnitrogenferNlizers

• Watervapor

• Mostabundantgreenhousegasandcontributesmosttothegreenhouseeffect

• GlobalconcentraNonhasnotchanged

• Notviewedasdrivingindustrial‐ageclimatechange

• Aerosols

• MicroscopicdropletsandparNcles

• Haveeitherawarmingorcoolingeffect

• Soot,orblackcarbonaerosols

• Causewarmingbyabsorbingsolarenergy

• ButmosttroposphericaerosolscooltheatmospherebyreflecNngtheSun’srays

• SulfateaerosolsproducedbyfossilfuelcombusNon

• Mayslowglobalwarming

• Atleastintheshortterm

• VolcanicerupNonsreducesunlightreachingtheearth

• ScienNstsesNmatetheinfluenceoffactorsoverEarth’senergybalance

• Radia7veforcing

• Theamountofchangeinenergythatagivenfactorcauses

• PosiNveforcingwarmsthesurface

• NegaNveforcingcoolsit

• Comparedwiththepre‐industrialEarth

• Today,theEarthisexperiencingradiaNveforcingof1.6wafs/m2

• Enoughtoaltertheclimate

Red — positive forcing (warming)Blue — negative forcing (cooling)

• Milankovitchcycles

• PeriodicchangesinEarth’srotaNonandorbitaroundtheSun

• AlterthewaysolarradiaNonisdistributedoverEarth’ssurface

• BymodifyingpafernsofatmosphericheaNng

• Thesecyclestriggerlong‐termclimatevariaNon

• SuchasperiodicglaciaNon

• Solaroutput

• SunvariesintheradiaNonitemits

• Ateachpeakofits11‐yearsunspotcycle

• ThesunemitsflaresstrongenoughtodisruptsatellitecommunicaNons

• ButvariaNoninsolarenergyhasnotbeengreatenoughtochangeEarth’stemperature

• Oceanabsorp7on

• Oceanshold50Nmesmorecarbonthantheatmosphere

• Andabsorbsitfromtheatmosphere

• CarbonabsorpNonbytheoceansisslowingglobalwarming

• ButnotprevenNngit

• WarmeroceansabsorblessCO2

• Becausegasesarelesssolubleinwarmerwater

• Whichaccelerateswarming

• Oceancircula7on

• Oceanwaterexchangestremendousamountsofheatwiththeatmosphere

• Movesenergyfromplacetoplace

• Thermohalinecircula7on

• Aworldwidecurrentsystem

• Warmer,fresherwatermovesalongthesurface

• carriesheattoEurope

• NorthAmericanDeepWater(NADW)

• ThedeepporNonofthethermohalinecirculaNon

• ConsisNngofdenser,salNer,coolwaterthatsinksandmovesdeepbeneaththesurface

• InterrupNngthermohalinecirculaNon

• Couldtriggerrapidclimatechange

• IfGreenland’sicemelts

• Freshwaterrunoffwoulddilutesurfacewaters

• Makingthemlessdense,andstoppingNADW

• DatasuggestthermohalinecirculaNonisslowing

• ElNiño‐southernoscilla7on(ENSO)

• SystemaNcshi\inatmosphericpressure,seasurfacetemperature,andoceancirculaNoninthetropicalPacificOcean

• Normally,windsblowfromeasttowestalongtheequator,fromhightolowpressure• Water“pilesup”inthewesternPacific

• Westward‐movingsurfacewatersallownutrient‐richupwellingalongthecoastofPeru.

• ElNiño

• OccurswhenairpressureincreasesinthewesternPacificanddecreasesintheeasternPacific

• Weakeningtheequatorialwinds

• Waterflowseastward,suppressingup‐wellings,shukngdowndeliveryofnutrientstoaquaNclife

• Coastalindustriesaredevastated;globalweatherischanged

• TheoppositeofElNiñoevents

• ColdsurfacewatersextendfarwestwardintheequatorialPacific

• weatherpafernsareaffectedinoppositeways

• ENSOcyclesareperiodic,occurringevery2‐8years

• Globallywarmingairandseatemperatures

• Maybeincreasingtheirfrequencyandstrength

Carbondioxideconcentra.onsincreasedfrom315ppmto383ppmbetween1958and2008

• ScienNstsmeasureatmosphericgasesdirectly• MaunaLoaobservatory

• Proxyindicators

• IndirectevidencethatserveassubsNtutesfordirectmeasurements

• Shedlightonpastclimate

• Icecaps,icesheets,andglaciersholdcluestoEarth’sclimate

• TrappedbubblesinicecoresshowatmosphericcomposiNon,greenhousegasconcentraNon,temperaturetrends,snowfall,solaracNvity,andfrequencyoffires

• Sedimentbeds

• Preservepollengrainsandotherplantremnants

• Treerings

• PrecipitaNonhistoryandfireoccurrence

• Packratmiddens

• Preserveplantpartsforcenturies

• Coralreefs

• Revealaspectsofoceanchemistry

• Climatemodels• Programsthatcombinewhatis

knownaboutatmosphericcirculaNon,oceancirculaNon,atmosphere‐oceaninteracNons,andfeedbackmechanisms• Simulateclimateprocesses

• ThesemodelsarebecomingmorereliableinpredicNngclimatechange

• ScienNficevidencethatclimatehaschangedsinceindustrializaNon

• Nowoverwhelmingandindisputable

• IntergovernmentalPanelonClimateChange(IPCC)

• AninternaNonalpanelofscienNstsandgovernmentofficialsestablishedin1988

• ThemostthoroughlyreviewedandwidelyacceptedsynthesisofscienNficinformaNononclimatechange

• Hasissuedaseriesofreportsonclimatechange

• 11/10/11‐5yearsle\tostopirreversibleclimatechange

• 11/18/11‐Increasingintensityofstormsduetoclimatechange

• FourthAssessmentReport(2007)

• ConsensusofscienNficclimateresearchfromaroundtheworld

• Summarizesthousandsofstudies

• Documentsobservedtrends

• Insurfacetemperature,precipitaNonpaferns,snowandicecover,sealevels,stormintensity,etc.

• Predictsfuturechanges

• Addressingimpactsofclimatechangeonwildlife,ecosystems,andhumansocieNes

• Discussespossiblestrategiestopursue

• Inresponsetoclimatechange

• TheIPCCreport

• Concludesthataveragesurfacetemperaturesonearthhavebeenrisingsince1906,mostlyinthelastfewdecades

• Attheendofthe21stcentury,temperatureswillbe1.8‐4.0°C(3.2‐7.2°F)higherthantoday

• Seasurfacetemperatureswillalsoincreaseasoceansabsorbmoreheat

• Maynothavemorestorms,butstormswillbestrongerandlonger

• SomeregionsarereceivingmoreprecipitaNonthanusual

• Andothersarereceivingless

• Droughtshavebecomemorefrequentandsevere

• Harmingagriculture,promoNngsoilerosion,reducingdrinkingwatersupplies,andencouragingforestfires

• Heavyrainshavecontributedtoflooding

• Killingpeople,destroyinghomes,andinflicNngbillionsofdollarsindamage

• HighlaNtudes=increasedprecipitaNon

• LowandmiddlelaNtudes=decreasedprecipitaNonwillworsenwatershortagesindevelopingcountries

• Mountaintopglaciersaredisappearing

• GlacierNaNonalPark

• Only27of150glaciersremainbutwillbegoneby2030

• ReducingsummerNmewatersupplies

• ArcNcandGreenlandicesheetsarerapidlymelNng

• AntarcNca

• IceshelvesthesizeofRhodeIslandhavedisintegrated

• Asicemelts,darker,less‐reflecNvesurfacesareexposed

• Absorbmoresunlight,causingmoremelNng

• Reducedalbedo

• Russia,theU.S.,Canada,andothernaNons• Arealreadyclaimingregionsofthe

ArcNcasicemelts• Togetunderwateroilandmineral

reserves

• Asglaciersandicemelt

• Increasedwaterwillflowintotheoceans

• Asoceanswarm,theyexpand

• Leadstobeacherosion,coastalfloods,andsaltwaterintrusionintoaquifers

• Stormsurge

• TemporaryandlocalizedriseinsealevelbroughtonbythehighNdesandwindsassociatedwithstorms

• CiNeswillbeflooded

• VulnerabilitybecametragicallyapparentwithHurricaneKatrinain2005

• Millionsofpeoplewillbedisplacedfromcoastalareas

• IPCCpredicts

• Meansealeveltobe18‐59cm(7‐23in)higherthantoday’sattheendofthe21stcentury

• Organismsareadaptedtotheirenvironments

• Sotheyareaffectedwhenthoseenvironmentschange

• Globalwarmingmodifiestemperature‐dependentphenomena

• TimingofmigraNon,breeding

• SpaNalshi\sintherangeoforganisms

• Animalsandplantswillmovetowardthepoles

• OrupwardinelevaNon• 20‐30%ofallspecieswillbethreatenedwithexNncNon

• Plantsactascarbonsinks

• Droughtsresultinfewerplants

• WhichmeansmoreCO2intheatmosphere

• Threatstocoralreefs:

• Warmerwaters(coralbleaching)

• Oceanchemistryisbecomingmoreacidic

• Impairingcoralgrowth

• Willgreatlyreducebiodiversity

• IncreasedprecipitaNonwillincreaseerosionandflooding

• WhichwillpolluteaquaNcsystems

• DecreasedprecipitaNon

• Willreducesurfacewaters

• Ecosystemgoodsandserviceswilldecrease