POTENTIAL CLIMATE POTENTIAL CLIMATE CHANGE IMPACTS ON THE CHANGE IMPACTS ON THE

CAPE & ISLANDSCAPE & ISLANDS

DAVID G. AUBREYDAVID G. AUBREY

WOODS HOLE GROUPWOODS HOLE GROUP

30 JANUARY 200330 JANUARY 2003

FIFTH STAKEHOLDER FIFTH STAKEHOLDER MEETINGMEETING

OUTLINEOUTLINE

• CLIMATE CHANGE DEBATECLIMATE CHANGE DEBATE• CLIMATE CHANGE IMPACTSCLIMATE CHANGE IMPACTS• RELATIVE SEA-LEVEL CHANGESRELATIVE SEA-LEVEL CHANGES• RELATIVE SEA-LEVEL RISE IMPACTSRELATIVE SEA-LEVEL RISE IMPACTS• CAPE AND ISLAND-SPECIFIC IMPACTSCAPE AND ISLAND-SPECIFIC IMPACTS• POSSIBLE RESPONSES TO CLIMATE POSSIBLE RESPONSES TO CLIMATE

CHANGE IMPACTSCHANGE IMPACTS• SUMMARYSUMMARY

CLIMATE CHANGE CLIMATE CHANGE DEBATEDEBATE

• Warmer air temperaturesWarmer air temperatures

• Warmer surface water temperaturesWarmer surface water temperatures

• Altered precipitation Altered precipitation patterns/hydrological patternspatterns/hydrological patterns

• Altered weather and climate (hurricanes, Altered weather and climate (hurricanes, storms, etc.)storms, etc.)

CLIMATE CHANGE CLIMATE CHANGE IMPACTS ON OCEANIMPACTS ON OCEAN

• INCREASES IN SEA LEVEL AND INCREASES IN SEA LEVEL AND SEA-SURFACE TEMPERATURE SEA-SURFACE TEMPERATURE (AFFECTING HURRICANES, (AFFECTING HURRICANES, NORTHEASTERS)NORTHEASTERS)

• DECREASES IN SEA-ICE COVERDECREASES IN SEA-ICE COVER• CHANGES IN SALINITY, CHANGES IN SALINITY,

ALKALINITY, WAVE CLIMATE, AND ALKALINITY, WAVE CLIMATE, AND OCEAN CIRCULATIONOCEAN CIRCULATION

• POSSIBLE CHANGES TO POSSIBLE CHANGES TO FREQUENCY, INTENSITY, AND FREQUENCY, INTENSITY, AND PATHS OF HURRICANESPATHS OF HURRICANES

• MODELING DATA DO NOT MODELING DATA DO NOT SUPPORT INCREASES IN SUPPORT INCREASES IN HURRICANES AND WAVESHURRICANES AND WAVES

• LITTLE INFORMATION ON LITTLE INFORMATION ON NORTHEASTERSNORTHEASTERS

HURRICANES, STORMS, AND WAVES

RELATIVE SEA-LEVEL CHANGES

• RELATIVE SEA-LEVEL CHANGES DUE TO LAND-LEVEL CHANGES AND WATER-LEVEL CHANGES

• LAND-LEVEL CHANGES RESULT FROM– TECTONICS– POST-GLACIAL REBOUND

RSL (CON’T)RSL (CON’T)

• WATER LEVEL CHANGES RESULT WATER LEVEL CHANGES RESULT FROM:FROM:– STERIC EFFECT (INCREASED WATER STERIC EFFECT (INCREASED WATER

TEMPERATURE AND LOWER SALINITY)TEMPERATURE AND LOWER SALINITY)

– EXCHANGE OF WATER WITH GLACIERS, EXCHANGE OF WATER WITH GLACIERS, ICE-CAPS (EARTH RHEOLOGY, ROTATION)ICE-CAPS (EARTH RHEOLOGY, ROTATION)

– HUMAN ACTIVITIES (WATER STORAGE HUMAN ACTIVITIES (WATER STORAGE SUCH AS GROUNDWATER, LAKES)SUCH AS GROUNDWATER, LAKES)

RSL: MEASUREMENTSRSL: MEASUREMENTS

• HOW DO WE MEASURE RELATIVE SEA HOW DO WE MEASURE RELATIVE SEA LEVELS?LEVELS?– DATING BURIED COASTAL VEGETATION DATING BURIED COASTAL VEGETATION

(SALT MARSHES, MANGROVES, ETC.): (SALT MARSHES, MANGROVES, ETC.): SPARSELY DISTRIBUTEDSPARSELY DISTRIBUTED

– TIDE GAUGES: MOST IN MID-LATITUDE TIDE GAUGES: MOST IN MID-LATITUDE NORTHERN HEMISPHERE, FEW IN MIDDLE NORTHERN HEMISPHERE, FEW IN MIDDLE OF OCEANS, CONTAMINATED BY EARTH OF OCEANS, CONTAMINATED BY EARTH MOVEMENTSMOVEMENTS

RSL HISTORY

RELATIVE SEA-LEVEL RELATIVE SEA-LEVEL RISE IMPACTSRISE IMPACTS

• Lowland inundation and wetland displacementLowland inundation and wetland displacement• Shoreline erosionShoreline erosion• More severe storm-surge floodingMore severe storm-surge flooding• Saltwater intrusion into estuaries and Saltwater intrusion into estuaries and

freshwater lagoonsfreshwater lagoons• Altered tidal range in rivers and baysAltered tidal range in rivers and bays• Changes in sedimentation patternsChanges in sedimentation patterns• Elevated sea-surface and ground temperaturesElevated sea-surface and ground temperatures

FUTURE RSL

RSL UNCERTAINTIESRSL UNCERTAINTIES

• MODELS SHOW ACCELERATION IN MODELS SHOW ACCELERATION IN RSL DURING 20RSL DURING 20THTH CENTURY; DATA CENTURY; DATA DON’TDON’T

• MODELS UNDERPREDICT RSL IN MODELS UNDERPREDICT RSL IN THE 20THE 20THTH CENTURY, COMPARED TO CENTURY, COMPARED TO OBSERVATIONSOBSERVATIONS

CAPE AND ISLAND SPECIFIC IMPACTS

• SEA-LEVEL RISE ON CAPE AND ISLANDS RANGES FROM 2.2 TO 2.7 MM/YEAR (ABOVE THE GLOBAL AVERAGE)

• GIESE ET AL. (1986) ESTIMATED LOSS

OF 80 ACRES PER YEAR ON CAPE COD DUE TO PASSIVE FLOODING FOR A MODERATE RSL SCENARIO, MANY TIMES THE LOSS DUE TO COASTAL EROSION!

POSSIBLE RESPONSES TO POSSIBLE RESPONSES TO CLIMATE CHANGE CLIMATE CHANGE

IMPACTIMPACT• ADAPTATION can beADAPTATION can be

– NATURALNATURAL– POLICY-DRIVEN, PRO-ACTIVE OR POLICY-DRIVEN, PRO-ACTIVE OR

REACTIVEREACTIVE– CATEGORIES: PROTECT, CATEGORIES: PROTECT,

ACCOMMODATE, AND RETREATACCOMMODATE, AND RETREAT

• MITIGATIONMITIGATION

SUMMARY REQUIREMENTSSUMMARY REQUIREMENTS

• INTEGRATED ASSESSMENTS ON INTEGRATED ASSESSMENTS ON GLOBAL AND REGIONAL BASESGLOBAL AND REGIONAL BASES

• ADAPTATION AND MITIGATION ADAPTATION AND MITIGATION OPTIONS IDENTIFIED AND OPTIONS IDENTIFIED AND CODIFIEDCODIFIED

• INTEGRATED MANAGEMENT ON A INTEGRATED MANAGEMENT ON A REGIONAL BASISREGIONAL BASIS