Name:

(Above)19cm-longsectionofaGISP2icecorefrom1855mdepthshowingannuallayers.Summerlayers(arrowed)aresandwichedbetweendarkerwinterlayers.

Photo credit:Anthony Gow/USACE/NOAA2001

Interpretations: ReadingtheBookofEarth

Togeologists,thisplanetofoursisn'tjustaplacewherewondrousthingshappeneveryday.TheEarthwestudyisadynamicsystem,constantlyproducingtheenvironmentsweallexperiencewhilesimultaneouslywritingitsautobiography.

Thelayersinsanddunes,glaciers,andlakebottomsarepagesofthisbook.

Geologistsandclimatescientiststranslatethesetomes,sothateveryonecanlearnEarth'sstory.Justaswereadoftheworld

ofdinosaurs,thelifeoftheancientseas,andlushjunglesthathaveturnedtodeserts,sotoodowereadofchangesintheskiesabovethem.Thetemperaturerangesandprecipitationpatternsthatgovernlifetodaywerenolessimportantinthepast.Glacialiceisavastrepositorycontainingsnowthatoncefell,dustthatflewthroughtheair,andbubbles̶tinysamplesoftheancientatmosphere.Theicecorepicturedaboveisjustoneexcerptfromthebook,witheachlayeroficepreservingoneyearofEarth'sstory.

ThroughthecourseofthisactivityyouwillinterpretaportionofthebookofEarthby

҉ Graphingandanalyzingicecoremethanedata,

҉ Calculatingtherateofchangeinmodernatmosphericconcentration,

҉ ComparingtheradiativeforcingofCO2andCH4quantitatively,and

҉ Predictingthenextchapterinthisstoryandtheplaceofhumanityinit.

(Above)Atmosphericconcentrationsofcarbondioxideandnitrousoxideoverthelast10,000kBPandsince1750(insetpanels).Measurementsareshownfromicecores(differentcoloursfordifferentstudies)andatmosphericsamples(redlines).Correspondingradiativeforcingsareshownontherightaxes.

©IPCC2007 Summary for Policymakers

(Left)Relativeforcingmechanismsofmodernclimatechange.

©UNEP/GRID-Arendal2005 Vital Climate Change Graphics

1.Openthecasestudy5.2studentdatasetusingyourspreadsheetprogram.

2.Createascatterplot(thekindconnectedwithaline)ofyourdatawithmethaneconcentrationonthey‐axisandageonthex‐axis.Reverseyourx‐axissothat0yearskBP(thepresent)isontheright.

3.Attachanimageorcopyofyourgraphtothisassignment.

4.Characterizeyourgraph.Whattrendsdoyounotice?Howdoesthepresentdifferfromthepastintermsofatmosphericmethaneconcentration?Bespecific.

5.Accordingtoyouricecoredata,whendoesthemostdrasticchangeinatmosphericmethaneconcentrationoccur?Fromthatdatetothepresent,whatistherateofincreaseinmethaneconcentrationinppbperyear?

6.Howdoesyouratmosphericconcentrationgraphformethanecomparetothoseofothergreenhousegases(shownonthefirstpageoftheactivity)?

7.RadiativeforcingisameasureofthepowerthatradiationhasperunitareaofEarth'ssurface.Thegreatertheradiativepoweroftheatmosphere,themoreheatenergyitmaintains,andthegreatertheimpact(orforce)ithasontheclimate.IfCO2hasaradiativeforcingof1W/m2at340ppmandCH4hasaradiativeforcingof0.1W/m2at850ppb,whichgasismorepowerful?

8.Howmanytimesgreateristheradiativeforcingofthemorepowerfulgas?

9.Basedonexperimentaldata*,doublingofthecurrentamountofmethaneintheatmospherewouldresultinatleasta0.5°Cincreaseinglobalaveragetemperature.Atthecurrentrateofchange,whenwouldtheatmospherereachadoubledconcentration?HowmuchhotterwouldEarthbeonaverageatthattimeduesolelytothedoublingofmethaneindegreesCandF?(1°C=0.56°F)

10.Giventhatthecurrentprimarysourcesofatmosphericmethanearelivestockactivityandextractionfromnaturalgasfieldsandcoalseams,doyouforeseeanincrease,decrease,orstabilityintherateofchangeinatmosphericmethane?Explainindetail.Howwillfutureclimatedifferaccordingto yourprediction?

11.Isitpossibletochangethefutureyoujustpredicted?Ifso,how?Ifnot,howwillwehavetochangetoliveinthisfutureclimate?

* Wuebbles,D.J.,andHayhoe,K.(2000).Atmosphericmethane:Trendsandimpacts.In:Non‐CO GreenhouseGases:ScientificUnderstanding,ControlandImplementation,J.vanHametal.(eds.),pp.425‐432.KluwerAcademicPublishers,Netherlands.Availableat