Future Climate Conditions in Fresno County and Surrounding ... · Future Climate Conditions in...

FutureClimateConditionsinFresnoCountyandSurroundingCounties

July2010

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FutureClimateConditionsinFresnoCountyandSurroundingCountiesGeosInstituteMarniE.Koopman,RichardS.Nauman,andJessicaL.Leonard

Supportforthisprojectwasprovidedby:The Kresge Foundation

The MAPSS Team at the USDA Forest Service Pacific Northwest Research Station

Conservation Grants Program

Acknowledgements:RayDrapekandRonNeilsonattheUSDAForestServicePacific

NorthwestResearchStationprovidedclimateprojectiondataaswellaslogistical

support.PeteVandeWater,JulieEkstrom,ScottPhillips,BrianCypher,andMichelle

Selmonprovidedvaluablefeedback.WealsoappreciateinsightsprovidedbyPhilMote

withtheOregonClimateChangeResearchInstitute.Thephotosinthisreportarefrom

USFWS,otherfederalsources,andBrianCypher.

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TABLEOFCONTENTS

Introduction 2

Modelsandtheirlimitations 3

Globalclimatechangeprojections 5

ClimateprojectionsforFresnoCountyandsurroundingcounties 6

Temperature 8

Precipitation 14

Snowpackandwateravailability 20

Vegetationandwildfire 21

Carbonstorage 24

SupportingStudies 25

Connectivity 26

Conclusions 27

LiteratureCited 28

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INTRODUCTION

FresnoCountyandthesurroundingcountiesofMadera,Kings,andTularearerichinhistory,culture,andbiologicaldiversity,inadditiontobeingvitalforthenation’sfoodproduction.Thesecountiesextendfromsemi‐desertandagriculturalvalleyfloorallthewaytothecrestoftheSierras.Changestothislandscapeduetoclimatechangearelikelytoaffectlocalresidentsandthenaturalresourcestheyrelyon. ClimaticchangesarealreadyunderwayacrossCaliforniaandarelikelytoincreaseinthecomingdecades.Changestothelocalclimatearelikelytoincludemorefrequentandintensestormsandfloods,extendeddrought,increasedwildfire,andmoreheatwaves.Localcommunitieswillneedtoplanforsuchchangesinordertopreventpotentiallycatastrophicconsequences.Climatechangepresentsuswithaseriouschallengeasweplanforthefuture.Ourcurrentplanningstrategiesatallscales(local,regional,andnational)relyonhistoricaldatatoanticipatefutureconditions.Yetduetoclimatechangeanditsassociatedimpacts,thefutureisnolongerexpectedtoresemblethepast.Thisreportprovidescommunitymembersanddecision‐makersinFresnoCountyandsurroundingcountieswithlocalclimatechangeprojectionsthatarepresentedinawaythatcanhelpthemmakeeducatedlong‐termplanning

decisions.TheclimatechangemodeloutputsinthisreportwereprovidedbytheUSDAForestServicePacificNorthwestResearchStationandmappedbyscientistsattheNationalCenterforConservationScienceandPolicy.Theresultspresentedinthisreportarecomplementarytoanin‐depthstudyofclimatechangeimpactstothecityofFresnoandmuchofthesurroundingarea,completedbyresearchersatCSUFresno(Harmsenetal.2008).Together,thesereportsandanupcomingcompanionreportonthevulnerabilitiesofsocio‐economicsystemsofFresnoCountytoclimatechangeprovidethebasisforinformedplanningefforts.Manyoftheimpactsofclimatechangeareinevitableduetocurrentlevelsofgreenhousegasemissionsalreadyintheatmosphere.Preparingfortheseimpactstoreducetheirseverityiscalled“adaptation”(seeboxbelow).Preventingevenmoresevereimpactsbyreducingfutureemissionsiscalled“mitigation.”MITIGATION=Reducingemissionstopreventrun‐awayclimatechange.Run‐awayclimatechangeoccurswhenpositivefeedbackskickintosuchanextentthatemissionsreductionsarenolongereffective.

ADAPTATION=Planningfortheinevitableimpactsofclimatechangeandreducingourvulnerabilitytothoseimpacts.

MODELSANDTHEIRLIMITATIONS

Todeterminewhatconditionswemightexpectinthefuture,climatologistscreatedmodelsbasedonphysical,chemical,andbiologicalprocessesthatformtheearth’sclimatesystem.Thesemodelsvaryintheirlevelofdetailandassumptions,makingoutputandfuturescenariosvariable.DifferencesamongmodelsstemfromdifferencesincurrentunderstandingofmanyofEarth’sprocessesandfeedbacks.Takenasagroup,however,climatemodelspresentarangeoflikelyfutureconditions. Mostclimatemodelsprojectthefutureclimateatglobalscales.Formanagersandpolicymakerstomakedecisions,however,theyneedinformationabouthowclimatechangewillimpactthelocalarea.TheMAPSS(MappedAtmosphere‐Plant‐SoilSystem)TeamatthePacificNorthwestResearchStationadjustedglobalmodeloutputtolocalandregionalscales(8km).TheIntergovernmentalPanelonClimateChange(IPCC)usesnumerousmodelstomakeglobalclimateprojections.Themodelsaredevelopedbydifferentinstitutionsandcountriesandhaveslightlydifferentinputsorassumptions.Fromthesemodels,theMAPSSTeamchosethreeglobalclimatemodelsthatrepresentedarangeofprojectionsfortemperatureandotherclimatevariables.ThesethreemodelsareHadley(HADCM,fromtheUK),MIROC(fromJapan),andCSIRO(fromAustralia).Whilethespecificinputsarebeyondthescopeof

HIGHCERTAINTY:Highertemperatures–Greaterconcentrationsofgreenhousegasestrapmoreheat.Measuredwarmingtracksmodelprojections.

Lowersnowpack–Highertemperaturescauseashiftfromsnowtorainatlowerelevationsandcauseearliersnowmeltathigherelevations.

Shiftingdistributionsofplants&animals–Relationshipsbetweenspeciesdistributionsandclimatearewelldocumented.MEDIUMCERTAINTY:Moreseverestorms–Changestostormpatternswillberegionallyvariable.

Changesinprecipitation–Currentmodelsshowwidedisagreementonprecipitationpatterns,butthemodelprojectionsconvergeinsomelocations.

Wildfirepatterns–Therelationshipbetweenfireandtemperaturehasbeenwelldocumented,butothercomponentsalsoplayarole(suchasvegetation,below). LOWCERTAINTY:Changesinvegetation–Vegetationmaytakedecadesorcenturiestokeeppacewithchangesinclimate.

Howcertainaretheprojections?

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thisreport,theyincludesuchvariablesasgreenhousegasemissions,airandoceancurrents,iceandsnowcover,plantgrowth,particulatematter,andmanyothers(Randalletal.2007).Thethreemodelschosenincludedspecificvariables,suchaswatervapor,thatwereneededinordertoruntheMC1vegetationmodel.Modeloutputswereconvertedtolocalscalesusinglocaldataonhistorictemperatureandprecipitationpatterns.TheclimatemodeloutputwasappliedtotheMC1vegetationmodel(Bacheletetal.2001),whichprovideddataonpossiblefuturevegetationtypes,biomassconsumedbywildfire,andcarbonsequestration.Theutilityofthemodelresultspresentedinthisreportistohelpcommunitiespicturewhattheconditionsandlandscapemaylooklikeinthefutureandthemagnitudeanddirectionofchange.Becausemodeloutputsvaryintheirdegreeofcertainty,theyareconsideredprojectionsratherthanpredictions(seeinsert).Somemodeloutputs,such

astemperature,havegreatercertaintythanotheroutputs,suchasvegetationtype(seeboxonpreviouspage).However,muchuncertaintyassociatedwithmodelprojectionsarisesduetouncertaintyinfuturegreenhousegasemissions.Weurgethereadertokeepinmindthatresultsarepresentedtoexplorethetypesofchangeswemaysee,butthatactualconditionsmaybequitedifferentfromthosedepictedinthisreport.Uncertaintyassociatedwithprojectionsoffutureconditionsshouldnotbeusedasareasonfordelayingactiononclimatechange.Thelikelihoodthatfutureconditionswillresemblehistoricconditionsisverylow,somanagersandpolicymakersareencouragedtobegintoplanforaneraofchange,eveniftheprecisetrajectoryorrateofsuchchangeisuncertain.

ClimateprojectionAmodel‐derivedestimateofthefutureclimate.

ClimatepredictionorforecastAprojectionthatishighlycertainbasedonagreementamongmultiplemodels.

ScenarioAcoherentandplausibledescriptionofapossiblefuturestate.Ascenariomaybedevelopedusingclimateprojectionsasthebasis,butadditionalinformation,includingbaselineconditionsanddecisionpathways,isneededtodevelopascenario.

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GLOBALCLIMATECHANGEPROJECTIONS

TheIPCC(2007)andtheU.S.GlobalChangeResearchProgram(2009)agreethattheevidenceis“unequivocal”thattheEarth’satmosphereandoceansarewarming,andthatthiswarmingisdueprimarilytohumanactivitiesincludingtheemissionofCO2,methane,andothergreenhousegases,alongwithdeforestation.Averageglobalairtemperaturehasalreadyincreasedby0.7°C(1.4°F)andisexpectedtoincreaseby2°‐6.4°C(11.5°F)withinthenextcentury(Figure1).TheIPCCemissionscenariousedinthisassessmentwasthe“business‐as‐usual”trajectory(A2)thatassumesthatmostnationsfailtoacttoloweremissions.IftheU.S.andotherkeynationsdrasticallyandimmediatelycutemissions,someofthemoresevereimpacts,likerun‐awayclimatechange,canstillbeavoided.

Duetoclimatesysteminertia,restabilizationofatmosphericgaseswilltakemanydecadesevenwithdrasticemissionsreductions.Reducingemissions(called“mitigation”)isvitaltopreventtheEarth’sclimatesystemfromreachingcertaintippingpointsthatwillleadtosuddenandirrevocablechanges.Inadditiontoemissionsreductions,planningforinevitablechangestriggeredbygreenhousegasesalreadypresentintheatmosphere(called“adaptation)willallowresidentsofFresnoCountyandthesurroundingareatoreducethenegativeimpactsofclimatechangeand,hopefully,maintaintheirquality‐of‐lifeasclimatechangeprogresses.Throughoutthisreportwepresentmidandlatecenturymodeloutputs.Midcenturyprojectionsarehighlylikely,duetogreenhousegasesalreadyreleased,butlate

centuryprojectionsmaychange,dependingonfutureemissions.

Figure1.Thelast1,000yearsinglobalaveragetemperatures,incomparisontoprojectedtemperaturesthrough2100.Drasticcutsingreenhousegasemissions(bestcasescenario)wouldleadtoanincreaseofabout2°Cby2100,whilethecurrenttrajectory(business‐as‐usual)willleadtoanincreasecloserto4.5°Candashighas6°C(adaptedfromIPCC2007).

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CLIMATEPROJECTIONSFORFRESNOANDSURROUNDINGCOUNTIES VariablesmodeledusingHADCM,CSIRO,MIROC,andthevegetationmodel(MC1)includetemperature,precipitation,vegetationtypeanddistribution,wildfire,andcarbonstorageinbiomass.Thesevariableswerecalculatedbasedonhistoricaldataformakingbaselinecomparisons,andwereprojectedoutto2100.TheseprojectionsrepresentalikelyrangeofpossiblefutureconditionsinFresnoCountyandthesurroundingcounties.Asclimatechangeplaysout,wemaybeabletomakemorecertainprojections.Wemayalsoexperiencesurprisesandunforeseenchainsofcause‐and‐effectthatcouldnothavebeenprojected.

Climatechangeprojectionsareprovidedhereinthreedifferentformats–asoverallaverages,asgraphsthatshowchangeovertime,andasmapsthatshowvariationacrosstheregion,butaveragedacrossyears.Wemappedclimateandvegetationvariablesforthehistoricalperiod(1961‐1990)andfortwofutureperiods(2035‐45and2075‐85).BecauseofthedifferenceinclimatebetweentheSierrasandthevalleyfloor,wecalculatedmodeloutputforeasternareasover1,000feetinelevationseparatelyfromotherareas(Figure2).Welabelthesetwoareasthe“Upper”and“Lower”FresnoCountyRegion.

Figure2.Areasreferredtointhisreportas“Upper”and“Lower”FresnoCountyregion.TheUpperFresnoCountyRegionisgenerallyabove1,000feetinelevationandisfoundintheeasternportionsofFresno,Madera,andTularecounties,whiletheLowerFresnoCountyRegionisgenerallybelow1,000feetinelevationandencompasseswesternportionsofFresno,Madera,andTularecountiesaswellasallofKingsCounty.

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Figure3.LandownershipinFresnoCountyandsurroundingcounties.

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TEMPERATURETheprojectionsfromallthreemodelsagree,withhighcertainty,onawarmerfutureforFresnoCountyandsurroundingcounties(Table1).TheupperFresnoCountyregionisprojectedtowarmslightlymorethanthelowerFresnoCountyregion.Otherstudiesindicateanincreaseinnighttimelowtemperatures.Daytimehighsarecurrentlybufferedbyhumidityfromirrigation.

Table1.ProjectedincreaseinaveragetemperatureintheupperandlowerFresnoCountyregions(seeFig.2fordetails),fromthreedifferentglobalclimatemodels.FutureprojectedtemperatureisshownaschangeindegreesFahrenheit,ascomparedtohistoricaverages(1961‐1990). Historic 2035‐45 2075‐85 Season Upper Lower Upper Lower Upper Lower Annual 46.4°F 62.3°F +2.5‐4.8°F +2.3‐4.3°F +5.2‐8.9°F +4.7‐8.2°F Summer 61.3°F 78.0°F +2.2‐6.0°F +2.0‐5.4°F +5.8‐11.0°F +5.2‐10.0°F Winter 33.9°F 47.0°F +2.2‐4.1°F +2.0‐3.8°F +4.1‐7.9°F +3.7‐7.4°F

Figure5.AverageannualtemperatureforthelowerFresnoregion,basedonhistoricdataandmodelprojectionsfromthreeglobalclimatemodels.

Figure4.AverageannualtemperaturefortheupperFresnoCountyregion,basedonhistoricdataandmodelprojectionsfromthreeglobalclimatemodels.

UpperFresnoCountyRegion

LowerFresnoCountyRegion

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Figures6and7.Averagehistoricandfuturemonthlytemperaturesinareasabove1000feetinelevation(top)andbelow1000feet(bottom).Bluebarsshowhistoricaveragetemperaturewhiletheorangeshaperepresentstherangeofprojectionsfromthethreeglobalclimatemodels.Theaverageforthetwofuturetimeperiodsisinpurple(2035‐45)andred(2075‐85).



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Figure8.Januarytemperature(top)andchangeintemperature(bottom),indegreesF.

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MIROC HADCM CSIRO

January Change in Temperature

Data provided by the US Forest Service Mapped Atmosphere-Plant-Soil System Study

Fresno Region

0 40 80 120 16020

Kilometers ´

Change in Temperature in Degrees Celsius

0 - 1

1.1

- 2

2.1

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3.1

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Increase

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MIROC HADCM CSIRO

JanuaryTemperature


Fresno Region

0 40 80 120 16020

Kilometers ´

Monthly Mean Temperature in Degrees Celsius

-10 - -8

-7 - -5

-4 - -3

-2 - 0

1 - 2

3 - 5

6 - 7

8 - 10

11 - 12

13 - 15

16 - 17

18 - 20

21 - 22

23 - 25

26 - 27

28 - 30

31 - 32

33 - 35

36 - 37

38 - 40

14 – 18.5

18.6 – 23

23.1 – 27.5

27.6 – 32

32.1 – 36.5

36.6 – 41

41.1 – 45.5

45.6 – 50

50.1 – 54.5

54.6 - 59

59.1 – 63.5

63.6 – 68

68.1 – 72.5

72.6 – 77

77.1 – 81.5

81.6 – 86

86.1 – 90.5

90.6 – 95

95.1 – 99.5

99.6 - 104

DegreesFahrenheit

0-1.8 1.9-3.4 3.5-6.2 6.3-7.8 7.9-9.6 9.7-11.3 11.4-13 13.1-14.4

ChangeindegreesFahrenheit

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Figure9.Apriltemperature(top)andchangeintemperature(bottom),indegreesF.

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MIROC HADCM CSIRO

April Change in Temperature


Fresno Region

0 40 80 120 16020

Kilometers ´


0 - 1

1.1

- 2

2.1

- 3

3.1

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4.1

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Increase

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MIROC HADCM CSIRO

AprilTemperature


Fresno Region

0 40 80 120 16020

Kilometers ´


-10 - -8

-7 - -5

-4 - -3

-2 - 0

1 - 2

3 - 5

6 - 7

8 - 10

11 - 12

13 - 15

16 - 17

18 - 20

21 - 22

23 - 25

26 - 27

28 - 30

31 - 32

33 - 35

36 - 37

38 - 40

14 – 18.5

18.6 – 23

23.1 – 27.5

27.6 – 32

32.1 – 36.5

36.6 – 41

41.1 – 45.5

45.6 – 50

50.1 – 54.5

54.6 - 59

59.1 – 63.5

63.6 – 68

68.1 – 72.5

72.6 – 77

77.1 – 81.5

81.6 – 86

86.1 – 90.5

90.6 – 95

95.1 – 99.5

99.6 - 104

DegreesFahrenheit

0-1.8 1.9-3.4 3.5-6.2 6.3-7.8 7.9-9.6 9.7-11.3 11.4-13 13.1-14.4


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Figure10.Julytemperature(top)andchangeintemperature(bottom),indegreesF.

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MIROC HADCM CSIRO

JulyTemperature


Fresno Region

0 40 80 120 16020

Kilometers ´


-10 - -8

-7 - -5

-4 - -3

-2 - 0

1 - 2

3 - 5

6 - 7

8 - 10

11 - 12

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MIROC HADCM CSIRO

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Fresno Region

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Kilometers ´


0 - 1

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Increase

14 – 18.5

18.6 – 23

23.1 – 27.5

27.6 – 32

32.1 – 36.5

36.6 – 41

41.1 – 45.5

45.6 – 50

50.1 – 54.5

54.6 - 59

59.1 – 63.5

63.6 – 68

68.1 – 72.5

72.6 – 77

77.1 – 81.5

81.6 – 86

86.1 – 90.5

90.6 – 95

95.1 – 99.5

99.6 - 104

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Figure11.Octobertemperature(top)andchangeintemperature(bottom)indegreesF.

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MIROC HADCM CSIRO

OctoberTemperature


Fresno Region

0 40 80 120 16020

Kilometers ´


-10 - -8

-7 - -5

-4 - -3

-2 - 0

1 - 2

3 - 5

6 - 7

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Fresno Region

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0 - 1

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14 – 18.5

18.6 – 23

23.1 – 27.5

27.6 – 32

32.1 – 36.5

36.6 – 41

41.1 – 45.5

45.6 – 50

50.1 – 54.5

54.6 - 59

59.1 – 63.5

63.6 – 68

68.1 – 72.5

72.6 – 77

77.1 – 81.5

81.6 – 86

86.1 – 90.5

90.6 – 95

95.1 – 99.5

99.6 - 104

DegreesFahrenheit

0-1.8 1.9-3.4 3.5-6.2 6.3-7.8 7.9-9.6 9.7-11.3 11.4-13 13.1-14.4


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PRECIPITATIONProjectionsforfutureprecipitationvariedamongthethreemodels(Fig.13‐14),butallthreemodelsagreedondrierconditions,onaverage,bylatecentury,especiallyinthespring(Fig.15‐16).InaseriesofreportsreleasedbytheCaliforniaEnergyCommission,asetofsixmodelsshowedconsensusonadrierclimateforCentralCalifornia(Westerlingetal.2009).Further,evenwithsubstantialincreasesinprecipitation,soilmoistureisexpectedtodeclineduetoincreasedairtemperatureandevaporation,effectivelycausingincreaseddroughtconditions.

Figure13.AverageannualprecipitationacrosstheupperFresnoregion(above1000feet),basedonhistoricaldata(blackline)andthreeglobalclimatemodelsprojectedoutto2100(averagesarefoundonthenextpage).

Figure14.AverageannualprecipitationacrossthelowerFresnoregion(below1000feet),basedonhistoricaldata(blackline)andthreeglobalclimatemodelsprojectedoutto2100(averagesarefoundonthenextpage).



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Table2.Averagehistorical(1961‐1990)precipitation,ininches,andchangesinprojectedprecipitationfortwotimeperiods(2035‐45and2075‐85)basedonprojectionsfromthreeglobalclimatemodels.Timeperiod Averageprecipitation(%changefromhistoric)

LowerFresnoregion UpperFresnoregionHistoric 9.4in. 29.9in.2035‐45 6.9‐10.6in.(‐27%to+13%) 21.7–33.6in.(‐28%to+12%)2075‐85 6.8‐8.8in.(‐28%to‐7%) 20.5–28.2in.(‐32%to‐6%)

Figure15.Monthlyhistoric(1960‐1991)andfutureprecipitationintheupperFresnoCountyregion(above1000feet),fortwotimeperiods(2035‐45and2075‐85).Averagefutureprecipitationwasderivedfromthreeglobalclimatemodels,andisexpectedtofallwithintheorangeandredareas.

Figure16.Monthlyhistoric(1960‐1991)andfutureprecipitationinthelowerFresnoCountyregion(below1000feet),fortwotimeperiods(2035‐45and2075‐85).Averagefutureprecipitationwasderivedfromthreeglobalclimatemodels,andisexpectedtofallwithintheorangeandredareas.



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Figure17.Januaryprecipitation(top)andchangeinprecipitation(bottom),inmm.

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January Change in Precipitation


Fresno Region

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Kilometers ´

Change in Precipitation in Millimeters

-105

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2

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-57

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-34

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JanuaryPrecipitation


Fresno Region

Monthly Mean Precipitation in Millimeters

197 - 216

217 - 235

236 - 255

256 - 274

275 - 294

295 - 314

315 - 333

334 - 353

354 - 372

373 - 392

0 - 20

21 - 39

40 - 59

60 - 78

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99 - 118

119 - 137

138 - 157

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Figure18.Aprilprecipitation(top)andchangeinprecipitation(bottom),inmm.

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AprilPrecipitation


Fresno Region


197 - 216

217 - 235

236 - 255

256 - 274

275 - 294

295 - 314

315 - 333

334 - 353

354 - 372

373 - 392

0 - 20

21 - 39

40 - 59

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119 - 137

138 - 157

158 - 176

177 - 1960 40 80 120 16020

Kilometers ´

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MIROC HADCM CSIRO

April Change in Precipitation


Fresno Region

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-105

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Figure19.Julyprecipitation(top)andchangeinprecipitation(bottom),inmm.

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JulyPrecipitation


Fresno Region


197 - 216

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256 - 274

275 - 294

295 - 314

315 - 333

334 - 353

354 - 372

373 - 392

0 - 20

21 - 39

40 - 59

60 - 78

79 - 98

99 - 118

119 - 137

138 - 157

158 - 176

177 - 1960 40 80 120 16020

Kilometers ´

20

35

-20

45

20

75

-20

85

MIROC HADCM CSIRO

July Change in Precipitation


Fresno Region

0 40 80 120 16020

Kilometers ´


-105

- -8

2

-81

- -58

-57

- -35

-34

- -11

-10

- 12

13 -

36

37 -

59

60 -

83

84 -

106

107

- 130


Page19

Figure20.Octoberprecipitation(top)andchangeinprecipitation(bottom),inmm.

19

61

-19

90

20

35

-20

45

20

75

-20

85

MIROC HADCM CSIRO

OctoberPrecipitation


Fresno Region


197 - 216

217 - 235

236 - 255

256 - 274

275 - 294

295 - 314

315 - 333

334 - 353

354 - 372

373 - 392

0 - 20

21 - 39

40 - 59

60 - 78

79 - 98

99 - 118

119 - 137

138 - 157

158 - 176

177 - 1960 40 80 120 16020

Kilometers ´

20

35

-20

45

20

75

-20

85

MIROC HADCM CSIRO

October Change in Precipitation


Fresno Region

0 40 80 120 16020

Kilometers ´


-105

- -8

2

-81

- -58

-57

- -35

-34

- -11

-10

- 12

13 -

36

37 -

59

60 -

83

84 -

106

107

- 130


Page20

SnowpackandWaterAvailabilityAstemperatureswarm,precipitationisexpectedtoincreasinglyfallasraininsteadofsnow.Inaddition,snowmeltisexpectedtooccurearlier(Hayhoeetal.2004).Historicaldataindicatesthatpeaksnowmassoccursfivedaysearlierthanitdidpriorto1930,andthatspringtemperaturesare1.2°Fwarmerthanpriorto1948(KapnickandHall2009).ProjectionsforfuturesnowpackthroughouttheSierraNevadarangeindicateapotentiallossof80%ofsnowpackbytheendofthecentury(Fig.21)underamoderatewarmingscenario.Snowpackisexpectedtobeevenlowerunderahighwarmingscenario(thecurrenttrajectory).Asincreasingtemperaturesleadtoshiftsfromsnowtorain,higher,butearlier,peakrunoffisexpected.Combinedwiththelikelihoodofmoreintenseprecipitationeventsandincreasingrain‐on‐snowevents,scientistspredictmoreintenserunoffandflooding(CANaturalResourcesAgency2009;Heetal.Inreview).TheCaliforniawatersystemisespeciallyvulnerabletoglobalwarmingduetoitsdependenceonmountainsnowaccumulationandthesnowmeltprocess(VicunaandDracup2007).Projectionsshowlowerstreamflow,lowerreservoirstorage,anddecreasedwatersupplydeliveriesandreliability,expectedtobeespeciallypronouncedlaterinthe21stCentury(Vicunaetal.2007).Groundwaterisalsoexpectedtodeclineduetoincreaseddemandandloweredrecharge.Earlierpeakrun‐off,moreintensestormsthatquicklywashthroughthesystem,andlowersnowpacklevelsallcontributetodeclininggroundwaterrecharge. Figure21.Current(left)andfuture(right)snowpackforCaliforniaonApril1(fromHayhoeetal.2004).Reductionsinsnowpackareafunctionofdecliningprecipitation,greaterproportionofprecipitationasraininsteadofsnow,andearlierspringsnowmelt.

Page21

VEGETATIONandWILDFIREThevegetationmodel(MC1)providedprojectionsforpredominantvegetationtypes(Figure22)andaverageannualbiomassconsumedbywildfire(Figure23).TheMC1vegetationmodelonlymakesprojectionsfornativevegetationtypesanddoesnotaccountforlandusechange(i.e.agricultureanddevelopment)orintroducedspecies(i.e.nonnativegrasses).Projectionsforchangesinvegetationtypesincludeashiftfromtemperategrasslandtosubtropicalgrasslandatlowerelevations.Becausethevalleyfloorisdominatedbynon‐nativegrasses,thisshiftmaynotberealized.Alossoftemperateshrublandonthevalleyfloorbymid‐centuryisalsoprojected,althoughmuchofthisvegetationtypehasalreadybeenlosttoagricultureanddevelopment.Athigherelevations,vegetationchangeisapparentinareasthatarecurrentlydominatedbysequoiaandmixedconifer(currentlysugarpine,whitefir,incensecedar,etc.).Lowerelevationconifers,suchasgraypine,mayspreadtohigherelevations,whilehighelevationspeciescouldbelost.Despitechangedgrowingconditions,vegetationcantakedecadesorcenturiestoadjust,especiallyathigherelevationswhereconditionswillbecomemorehospitabletoforestbutsoilwilltakedecadesorcenturiestodevelop.Mechanismsforvegetationchangeatlowerelevationsarelikelytobedrought,fire,invasivespecies,insectsanddisease.Westerlingetal.(2009)projectedsubstantialincreasesintotalaverageareaburnedbywildfire,withtheeasternportionsofFresno,Tulare,andMaderaCountiesexpectedtoexperience300‐400%greateracreageburnedby2085ascomparedtothehistoric(1961‐1990)amount(Figure24).Similarly,theMC1modelprojects2‐4timesgreaterbiomassconsumedbywildfire(Figure23)athigherelevationsbytheendofthecentury.

Page22

Figure22.TheMC1modelshowssuitablegrowingconditionsfornativetypesofvegetation,butnotactualvegetationornon‐nativevegetation.Land‐usechanges,suchasagricultureorhousing,arealsonotreflectedinthisoutput.Actualvegetationinthefuturewilldependnotonlyonclimateconditions,butalsoonlanduse,non‐nativespecies,andresponsetimeneededforchangesfromonetypetoanother(newforesttypesdonotoccurovernight,forexample,astheymayneeddecadesorcenturiestobecomeestablished).

19

61

-19

90

20

35

-20

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20

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MIROC HADCM CSIRO

VegetationType


Fresno Region

0 40 80 120 16020

Kilometers ´

MC1 Vegetation Classification

Subalpine Forest

Maritime Evergreen Needleleaf Forest

Temperate Evergreen Needleleaf Forest

Temperate Evergreen Needleleaf Woodland

Temperate Shrubland

Temperate Grassland

Temperate Desert

Subtropical Mixed Forest

Subtropical Mixed Savanna

Subtropical Shrubland

Subtropical Grassland

Subtropical Desert

Mixed High Elevation

High Elevation Grasslands

Page23

Figure23.AverageannualbiomassconsumedbywildfireinFresnoCountyandsurroundingcounties,shownforthehistoricalperiod(1960‐1991)andprojectedfortwofutureperiods(2035‐45and2075‐85),usingthreeglobalclimatemodels.

Figure24.Predictedchangeinburnedareain2085comparedtohistoricalperiod.Avalueof100%indicatesnochangewhileavalueof400%indicatesa4‐foldincrease.Resultsareshownfromtwoglobalclimatemodels.FigureadaptedfromWesterlingetal.(2009).

CNRM CM3 GFDL CM21

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-19

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MIROC HADCM CSIRO

AnnualBiomass Consumed


Fresno Region

0 40 80 120 16020

Kilometers ´

Consumed Biomass

0 - 11

12 - 23

24 - 34

35 - 46

47 - 57

58 - 69

70 - 80

81 - 92

93 - 103

104 - 115

116 - 126

127 - 138

in grams per square meter

Page24

CARBONSTORAGEAllthreeglobalclimatemodelsindicatealossofcarbonstoragebylate‐century(2075‐85),primarilyintheSierraNevadarange.Alossofcarbonstorageresultsfromvegetationdie‐backorwildfire.ThisindicatesthatportionsoftheSierraNevadarangecouldbecomeacarbonsource,ratherthansink,withinthenextcentury.ThisresultissupportedbyaUSDAForestServicestudyonforestmanagementstrategiesformaintainingcarbonstoresonnationalforestlandsinthisregion(USDA2009).Figure25.AverageannualcarbonstorageinvegetationinFresnoCountyandsurroundingcounties,shownforthehistoricalperiod(1960‐1991)andprojectedfortwofutureperiods(2035‐45and2075‐85),usingthreeglobalclimatemodels.

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MIROC HADCM CSIRO

AnnualVegetation Carbon


Fresno Region

0 40 80 120 16020

Kilometers ´

Carbon Stored in Vegetation

0 - 2,250

2,251 - 4,500

4,501 - 6,750

6,751 - 9,000

9,001 - 11,250

11,251 - 13,500

13,501 - 15,750

15,751 - 18,000

18,001 - 20,250

20,251 - 22,500

22,501 - 24,750

24,751 - 27,000

in grams per square meter

Page25

SUPPORTINGSTUDIES

TheCaliforniaEnergyCommission(CEC)sponsoredalargebodyofresearchintothepotentialimpactsofclimatechangeacrossthestate.Manyofthereportsfromthiseffortwerereleasedin2009.Forconsistency,authorsofthesereportsallusedthesamesetofglobalclimatemodelsformakingtheirprojections.Thesemodelsweredifferentthanthethreeusedinthisreport,whichwerechosenbyresearchersatthePacificNWResearchStationtorepresentarangeoffutureconditions.Evenwithdifferentmodels,however,theresultsfrommanyCECreportsagreewithorcomplementtheresultsinthisreport,providinggreaterconfidenceintheresultspresentedhere.Usingthesamevegetationmodel(MC1)butdifferentclimatemodelsthanours,Shawetal.(2009)alsoprojectsadeclineinconiferousforestintheeasternportionsofFresno,Madera,andTularecounties,withexpansionofhardwoodforest.Shrublandsarealsoexpectedtoexpand,attheexpenseofgrasslands.Inaddition,theirstudyprojectedsteepdeclinesinforageproductioninthefoothillsoftheSierrasinthesamethreecounties(Figure25).Inanotherstudy,Loarieetal.(2008)modeledpotentialrangeshiftsofendemicplantspeciesthroughoutCalifornia.Themodelingexerciserevealedthatupto1/3ofallspecieswillbeextirpatediftheyareunabletomovetonewareas.Speciesdiversityisexpectedtoremainhigherathigherelevationsandalongthecoast.Kueppersetal.(2005)modeledshiftsinrangefortwospeciesofoak,blueoakandvalleyoak,throughoutthestate,usingtwodifferentclimatemodels(oneregionalandoneglobal).BothoaksexperiencedrangecontractionsintheFresnoregionby2080‐2099,accordingtothemodels,butthegeographiccomplexityoftheareamayresultinrangeexpansionaswell.

Figure25.Netchangeinforageproductionby2070‐2099,basedontwoclimatemodelsundertheA2emissionsscenario.Orangeorbrownrepresentadeclineinforageproduction,whilebluerepresentsanincreaseinforageproduction.(FigurefromShawetal.2009)

Page26

CONNECTIVITY

Astheclimatechanges,animalsandplantsareexpectedtorespondinvariousways.Mostspecieswillneedtomovetonewareaswheretheclimateissuitable.Somespeciesareonlyabletomoveshortdistancesduetonaturallimitationssuchaslowdispersalrates,inhospitableterrain,oralackofdispersalagents.Otherspeciesmaybelimitedbydevelopment,roadplacement,orlossofhabitatinnewareas.Incontrast,weedyorinvasivespeciesareexpectedtoeasilymoveinresponsetothechangingclimateandcouldincreaseinabundanceandrange.InordertominimizethedeclineandpotentialextirpationofmanyofCalifornia’snativespecies,threeprimaryapproachestothedispersalproblem(outlinedabove)havebeenrecommended.Byfarthemostimportantapproachistomaintainandincreasehabitatconnectivityandcorridorsacrosscounties,regions,states,andeventheentirewesternU.S.Thisapproachrequiresalevelofcollaborationandcommunicationacrosslandownershipthatiscurrentlynon‐existent.AreasofFresnoCountyandthesurroundingcountieshavebeenidentifiedasespeciallyimportantforlong‐termmovementofanimalsandplantsamongnaturalareas(Figure26).Facilitateddispersal(translocation)isrecommendedforspecieswithlimitedabilitiesandopportunitiesfornaturaldispersal.Facilitateddispersalwillneedtobecarefullyconsideredandplanned,astherearemanypotentiallyundesirableconsequences.Inaddition,costandfailurerateareoftenhigh.Finally,aggressivecontrolofundesirableinvasiveandweedyspecieswillbeneededtoallowmoredesirablenativespeciestheopportunitytodisperseandbecomeestablishedinnewareas.Figure26.AreasimportantforhabitatconnectivityintheFresnoregion.Greenareasarelargelynaturalareaswhileyellowandredareasareimportantconnectorsthatwouldbemorecostlytoconserve(adaptedfromSpenceretal.2010).

Page27

CONCLUSIONS

Thepurposeofthisreportistoprovideup‐to‐dateclimateprojectionsforFresno,Madera,Kings,andTulareCountiesatascalethatcanbeusedincommunityplanningefforts.Byprovidingtheinformationthatlocalmanagers,decision‐makersandcommunitymembersneedtomakeday‐to‐daydecisionsandlong‐termplans,wehopetospurproactiveclimatechangeadaptationplanning.Manyoftheimpactsofclimatechangearealreadyprogressingandwillcontinuetoacceleratethroughoutthenextfewdecades,regardlessoffutureemissions.Forinstance,projectionsforthetimeperiodof20352045arehighlylikelytobecomereality.Whetherwelimitclimatechangetothislevelorcontinuetoprogresstowardsthelevelprojectedfor20752085andbeyondwilldependonwhethertheU.S.andotherkeynationschoosetoloweremissionsdrasticallyandimmediately.Theprojectionsprovidedinthisreportareintendedtoformthefoundationforcity,county,andregionaladaptationplanningforclimatechange.Ourprogram,calledtheClimateWise®program,strivestobuildco‐beneficialplanningstrategiesthatarescience‐based,aredevelopedbylocalcommunitymembers,andincreasetheresilienceofbothhumanandnaturalcommunitiesinacohesivemanner.Thisprocesswilltakeplaceinaseriesofworkshopsinvolvingexpertsinthefollowingsectors:naturalecosystems(terrestrialandaquatic),built(infrastructure,culverts,etc.),human(health,emergencyresponse,etc.),economic(agriculture,business,etc.)andcultural(NativeAmericantribalcustomsandrights,immigrantcommunitiesandcustoms,etc.).TheClimateWise®programisstructuredtobegintheplanningprocessinlocalcommunities,andto“scaleup”managementstrategiestothestateandfederallevelbyidentifyingneededchangesinpolicyandgovernancestructure.Duringthelocalplanningprocess,expertsfromdifferentsectorswillidentifybarrierstosoundmanagement,allowingustoaddresstheselimitingfactorsbycollaboratingwithlawmakers.PleasecontactMarniKoopmanattheNationalCenterforConservationScienceandPolicyformoreinformationortobecomeinvolvedinthisprocess([email protected];541‐482‐4459x303).

Page28

LITERATURECITED

Bachelet,D.,J.M.Lenihan,C.Daly,R.P.Neilson,D.S.Ojima,andW.J.Parton.2001.MC1:Adynamicvegetationmodelforestimatingthedistributionofvegetationandassociatedcarbon,nutrients,andwater‐atechnicaldocumentation.Version1.0.GTR‐508.Portland,OR:U.S.DepartmentofAgriculture,ForestService,PacificNorthwestResearchStation.Harmsen,F.,D.Hunsaker,P.VandeWater,andY.V.Luo.2008.MitigationandAdpatationStrategiesforClimateChangeinFresno,California.InstituteofClimateChangeOceansandAtmosphere,CollegeofScienceandMathematics,CSUFresno.Hayhoe,K.,D.Cayan,C.B.Field,P.C.Frumhoff,E.P.Maurer,N.L.Miller,S.C.Moser,S.H.Schneider,K.N.Cahill,E.E.Cleland,L.Dale,R.Drapek,R.M.Hanemann,L.S.Kalkstein,J.Lenihan,C.K.Lunch,R.P.Neilson,S.C.Sheridan,andJ.H.Verville.2004.EmissionsPathways,ClimateChange,andImpactsonCalifornia.ProceedingsoftheNationalAcademyofSciencesoftheUnitedStatesofAmerica101:12422–27.He,Z.,Z.Wang,C.J.Suen,andX.Ma.Inreview.ClimatechangeimpactsonwateravailabilityintheUpperSanJoaquinRiverwatershed,California.IPCC.2007.ClimateChange2007:SynthesisReport.ContributionofWorkingGroupsI,IIandIIItotheFourthAssessmentReportoftheIntergovernmentalPanelonClimateChange.CambridgeUniversityPress.Kapnick,S.andA.Hall.2009.ObservedchangesintheSierraNevadasnowpack:Potentialcausesandconcerns.CaliforniaClimateChangeCenter.CEC‐500‐2009‐016‐F.Kueppers,L.M.,M.A.Snyder,L.C.Sloan,E.S.Zavaleta,andB.Fulfrost.2005.ModeledregionalclimatechangeandCaliforniaendemicoakranges.PNAS102:18281‐18286.Loarie,S.R.,B.E.Carter,K.Hayhoe,S.McMahon,R.Moe,C.A.Knight,andD.D.Ackerly.2008.ClimatechangeandthefutureofCalifornia’sendemicflora.PloSONE3:1‐10.Randall,D.A.,R.A.Wood,S.Bony,etal.2007.ClimateModelsandTheirEvaluation.InClimateChange2007:ThePhysicalScienceBasis.ContributionofWorkingGroupItotheFourthAssessmentReportoftheIntergovernmentalPanelonClimateChange.Solomon,S.,D.Qin,M.Manning,etal.,Eds.CambridgeUniversityPress.Shaw,M.R.,L.Pendleton,D.Cameron,B.Morris,G.Bratman,D.Bachelet,K.Klausmeyer,J.MacKenzie,D.Conklin,J.Lenihan,E.Haunreiter,andC.Daly.2009.TheImpactofClimateChangeonCalifornia’sEcosystemServices.CaliforniaClimate

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ChangeCenter.CEC‐500‐2009‐025‐F.Spencer,W.D.,P.Beier,K.Penrod,K.Winters,C.Paulman,H.Rustigian‐Romsos,J.Strittholt,M.Parisi,andA.Pettler.2010.CaliforniaEssentialHabitatConnectivityProject:AStrategyforConservingaConnectedCalifornia.PreparedforCaliforniaDepartmentofTransportation,CaliforniaDepartmentofFishandGame,andFederalHighwaysAdministration.Accessed:http://www.dfg.ca.gov/habcon/connectivity/CANaturalResourcesAgency.2009.CaliforniaWaterPlanUpdate2009:IntegratedWaterManagement.Dept.ofWaterResources.Accessed07/27/2010athttp://www.waterplan.water.ca.gov/cwpu2009/index.cfmUSDA.2009.NationalForestCarbonInventoryScenariosforthePacificSouthwestRegion(California).Goines,B.andM.Nechodom,Eds.USGCRP.2009.GlobalClimateChangeImpactsintheUnitedStates.T.R.Karl,J.M.Melillo,andT.C.Peterson,Eds.CambridgeUniversityPress.Vicuna,S.,andJ.A.Dracup.2007.TheevolutionofclimatechangeimpactstudiesonhydrologyandwaterresourcesinCalifornia.ClimaticChange82:327–350.Vicuna,S.,E.P.Maurer,B.Joyce,J.A.Dracup,andD.Purkey.2007.TheSensitivityofCaliforniaWaterResourcestoClimateChangeScenarios.JournaloftheAmericanWaterResourcesAssociation43:482–498.Westerling,A.L.,B.P.Bryant,H.K.Preisler,T.P.Holmes,H.G.Hidalgo,T.Das,andS.R.Shrestha.2009.ClimateChange,Growth,andCaliforniaWildfire.CaliforniaClimateChangeCenter.CEC‐500‐2009‐046‐F.

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