Rob Thieler from U.S. Geological Survey Presentation - Connecticut ...

We need better science* to prepare our local responses toclimate change, especially in our coastal areas.(David Carter, Delaware Coastal Management)*science = better understanding of processes + better situation awareness

Past, Current and Projected GlobalTemperatureThe last 10,000 years have been ideal forthe development of human societies.This has been a unique time duringwhich climate varied very little andenabled humankind to flourish.

Sea-level rise rates since the Last GlacialMaximummwp-Iamwp-IbGlobal delta initiation(Stanley and Warne, 1994)U.S. Atlantic, U.K.wetland initiation;barrier island stability(Shennan and Horton, 2002;Engelhart et al., in press)Rate of SLR (mm/yr)Thousands of 14 C years before present(SLR rate based on Fairbanks, 1989)

Past, present, and potential future rates ofsea-level rise“Geologic past”(Fairbanks, 1989;Horton et al. 2009)“Projections”(Rahmstorf, 2007)“Instrumental record”(Church and White, 2006)Rate of SLR (mm/yr)Years before present

Historic and Projected Sea-level RiseIPCC AR4A1B envelopeSeveral projections suggest ~60-150+cm rise is possible over the next century(modified after Rahmstorf, 2007; A1B envelope from IPCC, 2007)(modified after Rahmstorf, 2007; AR4 data from Bindoff, 2007)

Issue: Global variability in SLREarth is still undergoingisostatic adjustmentfrom deglaciation(Illinois Geological Survey)(Horton et al., 2009)

Issue: Global variability in SLRLoss of the WestAntarctic Ice Sheet cancause up to 25% moreSLR on the U.S. coast.(Eric Steig)(Bamber et al., 2009)

Issue: Regional variability in SLR(Yin et al.,2009)(Hu et al., 2009)Regional changes in circulation and ocean warming can increasesea level by tens of centimeters, for example in the northeasternU.S. (north of Cape Hatteras).

Importance of Spatial Scale

Importance of Temporal ScaleShort Term VarianceShoreline PositionSeawardLong TermTrendTimeShort-term Variance(hours to decade)Storm impact/recoveryAnnual cyclesEl NiñoLong-term Trend(decades to centuries)Sediment deficit or surplusSea-level rise

Coastal Vulnerability to Sea-level Rise:A Preliminary National Assessment(Thieler and Hammar-Klose 1999, 2000a, 2000b)Vulnerability Ranking

Coastal Sensitivity to Sea-Level Rise:A Focus on the Mid-Atlantic RegionU.S. Climate ChangeScience ProgramSynthesis and AssessmentProduct 4.1

Coastal Elevation Data• Elevation is a critical factor inassessing potential impacts(specifically, inundation)• Current elevation data do notprovide the degree of confidenceneeded for quantitativeassessments for local decisionmaking• Collection of high-qualityelevation data (lidar) would bevaluable(Gesch et al., 2009)

Coastal Elevation Datain Connecticut(Walters, USGS NE lidar program)

Eastern North Carolina0 15 30 60 90 120KilometersElevation source: 30-m DEMElevation source: 3-m lidar dataDark blue Land ≤ 1 meter elevationLight blue Area of uncertaintyassociated with 1 meter elevation• High quality elevation datareduce uncertainty of potentiallyinundated areas(Gesch et al., 2009)

Coastal Flooding in Charleston, SC(Built environment impacts)• NOAA NWS Charlestonissues shallow coastalflooding advisories for 7 fttides• 7 ft tides typically predictedto occur twice a year(NOAA CSC)• With 1.6 ft of relative sealevelrise, this advisorycould be issued 355 timesper year

But… the coast is not like a bathtubMiamiNew YorkBoston

Mid-Atlantic Assessment of PotentialDynamic Coastal Responses to Sea-level RiseBluff erosionOverwashIsland Breaching(Gutierrez et al., 2009)Threshold Crossing

Coastal Wetlands RespondDynamically to Environmental ChangeR. CarlsonWetland Vertical DevelopmentMineral sediment depositionPlant matter accumulation - soil(root production/decomposition)CompactionShrink-SwellD. Cahoon(Cahoon et al., 2009)D. Cahoon

So, what can happen?Bluff erosionOverwashIsland BreachingListedSpeciesImpactsThreshold CrossingUrban InundationWetland LossR. CarlsonWater Quality ReductionEcosystem ChangeInfrastructure Failure

Science strategy to address the challengeof climate change and sea-level riseMonitor ModernProcesses andEnvironmentsLearn fromthe PastImprove PredictiveCapabilityImprove Understandingof Societal ImpactsSupport Decision Making(Thieler et al., 2009)

Informing Decisions in a Changing ClimateNational Research Council (2009)The end of “Climate Stationarity” requires thatorganizations and individuals alter their standardpractices and decision routines to take climatechange into account. Scientific priorities andpractices need to change so that the scientificcommunity can provide better support todecision makers in managing emerging climaterisks.• Decision makers must expect to be surprisedbecause of the nature of climate change andthe incompleteness of scientificunderstanding of its consequences.• An uncertainty management frameworkshould be used because of the inadequaciesof predictive capability.

Sea-level rise impacts: A multivariate problem withuncertainties everywhereDrivingForcesGroundwaterImpactWetland LossHabitat LossAdaptationPlanningResponseClimate Change&Sea LevelRisePhysical& BiologicalProcessesCoastal ErosionPotentialImpactsManagementDecisionsInitialConditionsInundationSafety

Mapping Erosion Risk Using Bayesian NetworksProbability of shoreline erosion >2 m/yrNew YorkBostonD.C.CharlestonMiami(Gutierrez et al., 2011)

Mapping Prediction UncertaintyHigher probability = higher certainty of outcome• Uncertainty map can beused to identify wherebetter information isneeded• Areas of low confidencerequire• better input data• better understanding ofprocesses• Can use this map tofocus researchresources(Gutierrez et al., 2011)

Summary• Future sea-level rise is problematic• It is a certain impact (we have already made a commitment toseveral centuries of SLR)• It is an uncertain impact (rates and magnitudes poorlyconstrained; human response unknown)• Effective climate change decision support willrequire changes in how we do science and howdecision makers assimilate and use scientificinformation• Probabilistic approaches have many applications• Convey what we know and what we know we don’t know• Synthesize data and models• Provide basis to focus research resources• Furnish information to support decision-making