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Systems Thinking and Modeling Climate Change Amy Pallant, Hee-Sun Lee, and Sarah Pryputniewicz Youknowtheeffectsoftheproverbialbutterflyflappingitswings.Butwhatabout anautomobiledriver?Canasingledriver’sactionsaffectEarth’sclimate?Earth’s systemsarecomplexandfullofsurprisinginterdependencies.Howdowehelp studentsunderstandthosecomplexitiesandseekanswerstotheautomobile question,consideringcumulativeandglobaleffects?Oneapproachistoemphasize systemsthinkinginscienceeducation. Systemsthinkingsuggeststhatyoucanbestunderstandacomplexsystemby studyingtheinterrelationshipsofitscomponentpartsratherthanlookingatthe individualpartsinisolation.Asystemsapproachhelpsstudentsunderstand interrelatedelements,feedbackloops,andinthiscase,afocusonthewholeEarth (CenterforEcoliteracy2012).Withongoingconcernabouttheeffectsofclimate change,usinginnovativematerialstohelpstudentsunderstandhowEarth’ssystems connectwitheachotheriscritical. Modeling Earth's climate ThisarticledescribestheHigh‐AdventureScienceonlineclimatechangecurriculum called“ModelingEarth’sClimate”developedattheConcordConsortium(see"Onthe web").Thisfree,innovativecurriculumincorporatesdynamiccomputermodels developedintheNetLogomodelingenvironment(see"Ontheweb")thatenable studentstovisualizethecomplexinteractionsrelatedtoclimatechangescience.The modelsaredesignedtoallowstudentstochangevariablestohelpthemdiscover howtheindividualpartsrelatetothewholesystem.Whilewedon'texpectthe studentstounderstandeverysinglevariablethataffectsclimatechange,this approachhelpsstudentsmakesenseofhumaneffectsonEarth’ssystem. The models OurmodelsareidealforexploringEarthsystemscienceandhumanimpactonthe Earth.Themodelssimulatechangesinasystemandarebasedonmathematical algorithmsthatapproximatefundamentalphysicallaws(PallantandTinker2004). Researchshowsthatcomputationalmodelsandsimulationsallowstudentsto understandthroughexplorationthebehaviorofsystemsthataredifficultto understandbyothermeans(FeurtzeigandRoberts1999;Horwitz1999).Muchas scientistsdo,studentscanexperimentwithmodelsbycontrollingconditionsatthe start(parameters)andduringarun;theycanexplorecauseandeffectbecausethey canobservethechangesinthemodelsthatemergefromfundamentalscience‐based rules.Themodelshavevividgraphicsandrunquickly,sostudentscanrunmultiple experimentstogaininsightsbycarefullyobservingchangestothesystem.Thus, studentscanlearnbothcontentandtheprocessofsciencebyexperimentingwith themodels. IntheModelingEarth’sClimatecurriculumstudentsbeginbyusingacomputer modeltoexploretheeffectofcarbondioxideonglobaltemperature.Themodel helpsstudentsseehowcarbondioxidetrapsinfraredradiation,inturnincreasing thetemperature.StudentscanincreaseordecreaseCO2amountsinthemodeland observehowthechangesaffectthesystembyinterpretingtheoutputgraphtothe leftofthemodel(Figure1).Byexperimentingwithextremes—addinglotsofCO2or removingmostoftheCO2—andpayingattentiontotheresultinggraph,students discoverforthemselvestherelationshipbetweenatmosphericcarbondioxideand temperature. Studentsencounterincreasinglycomplexmodelsastheyproceedthroughthe curriculumandshifttheirfocusfromthepartstothewhole.Theylearnthatthe actualtemperatureincreaseonEarthisgreaterthanwhatwouldbeexpectedifonly carbondioxidelevelswereconsidered.Thecurriculumintroducesnewvariables, suchaswatervapor,intothemodelandasksstudentstoexplaintherelationships amongtheinterrelatedpartsofthesystem.Studentscan,inthiscase,explorethe effectoftwodifferentgreenhousegasesanddiscovertheinterrelationshipsamong thelevelsofCO2,theamountofwatervaporintheatmosphere,andtheeffectson atmospherictemperatures. Feedback loops Feedbackloopscanenhanceorbufferchangesthatoccurinasystem.Positive feedbackamplifieschanges,andnegativefeedbacktendstodampenchanges (ScienceEducationResourceCenteratCarletonCollege2003).Inclimatechange, positivefeedbackacceleratestemperaturerise;negativefeedbackdeceleratesit. TheModelingEarth’sClimatecurriculumexploresdifferentfeedbackloops.For example,becauseiceisbothlightcoloredandreflective,sunlightthathitsice bouncesbacktospace,limitingwarming.However,asEarthgetswarmer,icemelts, revealingoceanorland,whicharedarkerthaniceandthereforeabsorbmoreofthe sun’senergy.Thisleadstomorewarming,whichinturnleadstomoreicemelting, andsooninthispositivefeedbackloop.Inthecurriculum,studentscanuseamodel tochangethepercentoficecoveroramountofgreenhousegasesandcorrelate thesechangestochangesinEarth’stemperature. Anotherfeedbackloophighlightedinthecurriculumistheeffectsofcloudcoveron Earth’stemperature.This,too,isabalancebetweensunlightreflectedoffcloudsand awayfromEarth(acoolingeffect)andinfraredradiationfromEarthabsorbedby cloudsandre‐radiatedintotheatmosphere(awarmingeffect).Inthemodel, studentscanchangetheamountofcloudcoverandthenanalyzetheoutputgraph (Figure2).(SeeKahn,p.xxofthisissue,formoreabouttheeffectofcloudson climate.)Finally,thecurriculumalsomodelstherelationshipsamongCO2, temperature,anddissolvedCO2intheoceans.Studentscanexplorewhathappensto thelevelofCO2intheairandoceansasatmospherictemperaturechanges.Such feedbackloopsarecomplexinthemselvesandareevenmorecomplexwhen consideredaspartofanintegratedclimatesystem. Climate models are complex Ourbesthopeofunderstandinghowglobaltemperaturechangesovertime,and howhumansmaybeaffectingit,liesintheclimatemodelsscientistshave developed.Actualclimatemodelsaresomeofthemostcomplexmodelsinallfields ofscience.Clearly,thecurriculummodelsaremuchsimpler,yettheyprovideuseful toolstoteststudentideas,makepredictions,andunderstandsystemthinking. ModelingEarth’sClimatescaffoldsstudentthinkingbyfocusingonhowthemodel representspartsofthesystem,theinteractionswithinthesystem,andthemodel limitations.Thecurriculumdoesthisbyaskingexplicitquestionsaroundmodels suchas“Howdoesthelevelofcarbondioxideaffectthelevelofwatervaporinthe atmosphere?”“Howcanyoutellthatamodelisgood?""Whatkindsoftestscanyou runtoassessthevalidityofthemodel?” AFrameworkofK‐12Education:Practices,CrosscuttingConcepts,andCoreIdeas (NRC2012)statesthatmodelscanbevaluableforexploringasystem’sbehaviors. Bysimulatingclimateinthepast,scientistscanseehowwellthemodelscompareto real‐worlddataandjudgehowtheymightpredictthefuture.TheHigh‐Adventure Sciencecurriculumalsohasstudentscomparemodeloutput—andtheirown conclusions—toreal‐worlddata. Asstudentsincreasethecomplexityofthemodels,theymovefromavaguesense that“everythinginteracts”tomoreconcreteexamplesofthephysical,chemical, biological,andhumaninteractionsrelatedtoclimatechangeoutcomesemerging fromthemodel.Embeddedassessmentsaskstudentstodescribeexplicitlythe behaviorofthesystemanditsmanyinteractingvariables,aswellasthecause‐and‐ effectrelationshipsinthesystem.Forexample,studentsmustreporthowchanges intheamountoficecoveringEarth’ssurfacecanaffectEarth’stemperature.Student responsestothisquestionincluded:“Themoreicecoverage,thecolderitwillget becausethesun’sraysarereflectedbackoutoftheatmosphere,”and,“Whenthere ismoreice,theicewillreflectalloftheenergyfromthesunandthereforetheEarth willbealotlesswarm.”Thistypeofquestionmakesstudentsthinkaboutthe interrelationshipsinthesystem.Askingstudentstoexplainthemechanismsof complexfeedbackloopsalsorequireshigher‐orderthinkingaboutinterrelated variables. Wehaveanalyzedstudentpre‐andpost‐testworkfor260middleandhighschool EarthScienceandEnvironmentalscienceclasses.Thetestincludeditemsthat focusedoncontentandnatureofscienceskills,consistingofmultiplechoiceand short‐answerquestions.Weconcludedthatstudentsofalllevelscanimprovetheir systemsthinkingmodeledinourclimatechangecurriculum.Thetestcanbefound ontheHigh‐Adventurewebsite(see"Ontheweb"). Human interactions and the climate system Youcan’tstudyclimatechangethesedayswithoutlookingspecificallyat anthropogeniccausesofchange.ClimateLiteracy,TheEssentialPrinciplesofClimate Science(U.S.GlobalChangeResearchProgram2009)states:“Theoverwhelming consensusofscientificstudiesonclimateindicatesthatmostobservedincreasein globalaveragetemperaturessincethelatterpartofthe20thcenturyisverylikely duetohumanactivities,primarilyfromincreasesingreenhousegasconcentrations resultingfromburningoffossilfuels.”(p.6)Thisbringsusbacktoouroriginalsetof questions:CanasingleautomobiledriveraffectEarth’sclimateandhowdowehelp studentslearnabouttheroleofhumansinchangingclimate?TheHigh‐Adventure Sciencecurriculumincludesopportunitiesforstudentstoexplorehowhuman‐ producedemissions(basedonburningfossilfuels)canchangeaverageEarth temperaturesovertime.Studentstestwhathappenswhentheyincreasehuman‐ producedgreenhousegasemissionsandwhathappenswhentheyreducehuman‐ causedemissions.Thelevelofemissionsisonemorevariableinthecomplexsystem thatismodeled.However,themodelaloneisnotenough;studentsmustalso compareoutcomestoreal‐worlddata.Thecurriculumhasstudentsanalyzeclimate changebasedonicecoredata(Figure3),oceanatmospheredata,andtheKeeling curvegraphsofongoingatmosphericchangeinCO2concentration,amongothers. Climatechangescienceiscomplex,andstudentsarenotexpectedtomasterevery detailthroughthecurriculum.Butgreatercomprehensiondoesrequiresystems thinking,namelytheabilitytounderstandhowvariouscomponentsinfluenceeach otherwithinacomplexsystem,themodelsusedtorepresentthesesystems,andthe interconnectionsamongthecomponentparts. TheFrameworkincludesabroaderrangeofideasinEarthandSpacesciencethan previousefforts.Coreideasincludefocuson1)Earth’sSystems,2)Earthandhuman activity,and3)anunderstandingofscientificpractices.Prominentinallthreeof thesecoreideasisclimatechangescience.TheFrameworkspecifiesthatstudents shouldlookatfeedbackloops,exploreinterconnectedfeaturesofEarth’sclimate system,comparehistoricandpresentclimatechange,aswellasstudythewaysin whichhumanactivitiesrelatetoEarth’sprocesses.TheModelingEarth’sClimate curriculumstronglyintegratesthesecoreconcepts.(NationalResearchCouncil, 2012,p196‐198). Conclusion Howweexamineproblemsdependsinpartonourworldview.Withanysystemthe wholeisdifferentthanthesumofitsparts.TheHigh‐AdventureScienceModeling Earth’sClimatecurriculumengagesstudentsinsystemsthinking,enablingthemto constructtheirownknowledgeonfactorsthatinfluenceclimatechange,compareit todatafromthescientificcommunity,andthinkcriticallyaboutcomplexitiesof climatechange. AmyPallant([email protected])istheprincipalinvestigatorontheHigh‐ AdventureScienceproject,andSaraPryputniewicz([email protected])is aresearchassistant,bothattheConcordConsortiuminConcord,Massachusetts;Hee‐ SunLee([email protected])isavisitingassistantprofessorattheUniversity ofCalifornia,SantaCruz. Acknowledgements TheauthorthanksDr.R.Tinkerforhisworkondevelopingthemodelsinthe curriculum.ThisworkissupportedbytheNationalScienceFoundation(NSF)under grantDRL‐0929774.Anyopinions,findings,andconclusionsorrecommendations expressedinthispaper,however,arethoseoftheauthorsanddonotnecessarily reflecttheviewsoftheNSF. On the web ConcordConsortium:www.concord.org/projects/high‐adventure‐science NetLogo:http://ccl.northwestern.edu/netlogo/ References CenterforEcoliteracy.2012.Exploresystemsthinking.www.ecoliteracy.org/nature‐ our‐teacher/systems‐thinking Feurtzeig,W.,andN.Roberts.1999.Modelingandsimulationsinscienceand mathematicseducation.NewYork:Springer. Horwitz,P.1999.Designingcomputermodelsthatteach.InW.FeurzeigandN. Roberts(Eds.),ModelingandSimulationinScienceandMathematicsEducation (pp.179‐196).NewYork:Springer. NationalResearchCouncil.2012.AFrameworkforK‐12scienceeducation:Practices, crosscuttingconcepts,andcoreideas.Washington,DC:TheNationalAcademies Press. Pallant,A.,andR.Tinker.2004.Reasoningwithatomic‐scalemoleculardynamics models.JournalofScienceEducationandTechnology13:51–66. ScienceEducationResourceCenteratCarletonCollege.2003.FeedbackLoops. Retrievedfrom.http://serc.carleton.edu/introgeo/models/loops.html U.S.GlobalChangeResearchProgram.2009.Climateliteracy:Theessential principlesofclimatesciences. http://downloads.climatescience.gov/Literacy/Climate%20Literacy%20Booklet %20Hi‐Res.pdf Figure1:ClimateModel.Thismodelallowsstudentstofollowenergy(representedby yellowarrows)fromthesunastheyinteractwithgreenhousegases(representedby greendots0andtheEarth’ssurfacewheretheyarereflectedasinfraredradiation (representedbyredarrows)orabsorbedasheat.Studentscanchangetheamountof CO2intheatmosphereAsstudentsincreasetheC02thetemperatureincreasesasseen inthegraph. Figure2:Thismodelallowsstudenttochangethecloudcovertoseehowanincrease inclouds,inthiscase,lowerstemperature.Studentsobservetherelationshipbetween cloud‐cover,incomingsolarradiation(yellowarrows),infraredradiations(red arrows)greenhousegases(blueandgreendots)andland,oceanandicetohelp explaintheresultinggraph. Figure3.Atmosphericcarbondioxideconcentrationduringthepast417,000years. http://upload.wikimedia.org/wikipedia/commons/8/88/CO2‐417k.png