Transcript POTENTIAL CLIMATE CHANGE IMPACTS ON THE CAPE & ISLANDS

POTENTIAL CLIMATE
CHANGE IMPACTS ON THE
CAPE & ISLANDS
DAVID G. AUBREY
WOODS HOLE GROUP
30 JANUARY 2003
FIFTH STAKEHOLDER
MEETING
OUTLINE
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CLIMATE CHANGE DEBATE
CLIMATE CHANGE IMPACTS
RELATIVE SEA-LEVEL CHANGES
RELATIVE SEA-LEVEL RISE IMPACTS
CAPE AND ISLAND-SPECIFIC IMPACTS
POSSIBLE RESPONSES TO CLIMATE
CHANGE IMPACTS
• SUMMARY
CLIMATE CHANGE
DEBATE
• Warmer air temperatures
• Warmer surface water temperatures
• Altered precipitation
patterns/hydrological patterns
• Altered weather and climate (hurricanes,
storms, etc.)
CLIMATE CHANGE
IMPACTS ON OCEAN
• INCREASES IN SEA LEVEL AND SEASURFACE TEMPERATURE
(AFFECTING HURRICANES,
NORTHEASTERS)
• DECREASES IN SEA-ICE COVER
• CHANGES IN SALINITY,
ALKALINITY, WAVE CLIMATE, AND
OCEAN CIRCULATION
HURRICANES, STORMS,
AND WAVES
• POSSIBLE CHANGES TO
FREQUENCY, INTENSITY, AND
PATHS OF HURRICANES
• MODELING DATA DO NOT
SUPPORT INCREASES IN
HURRICANES AND WAVES
• LITTLE INFORMATION ON
NORTHEASTERS
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)
• WATER LEVEL CHANGES RESULT FROM:
– STERIC EFFECT (INCREASED WATER
TEMPERATURE AND LOWER SALINITY)
– EXCHANGE OF WATER WITH GLACIERS, ICECAPS (EARTH RHEOLOGY, ROTATION)
– HUMAN ACTIVITIES (WATER STORAGE SUCH
AS GROUNDWATER, LAKES)
RSL: MEASUREMENTS
• HOW DO WE MEASURE RELATIVE SEA
LEVELS?
– DATING BURIED COASTAL VEGETATION
(SALT MARSHES, MANGROVES, ETC.):
SPARSELY DISTRIBUTED
– TIDE GAUGES: MOST IN MID-LATITUDE
NORTHERN HEMISPHERE, FEW IN MIDDLE
OF OCEANS, CONTAMINATED BY EARTH
MOVEMENTS
RSL HISTORY
RELATIVE SEA-LEVEL
RISE IMPACTS
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Lowland inundation and wetland displacement
Shoreline erosion
More severe storm-surge flooding
Saltwater intrusion into estuaries and
freshwater lagoons
• Altered tidal range in rivers and bays
• Changes in sedimentation patterns
• Elevated sea-surface and ground temperatures
FUTURE RSL
RSL UNCERTAINTIES
• MODELS SHOW ACCELERATION IN
RSL DURING 20TH CENTURY; DATA
DON’T
• MODELS UNDERPREDICT RSL IN
THE 20TH CENTURY, COMPARED TO
OBSERVATIONS
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
CLIMATE CHANGE IMPACT
• ADAPTATION can be
– NATURAL
– POLICY-DRIVEN, PRO-ACTIVE OR
REACTIVE
– CATEGORIES: PROTECT,
ACCOMMODATE, AND RETREAT
• MITIGATION
SUMMARY REQUIREMENTS
• INTEGRATED ASSESSMENTS ON
GLOBAL AND REGIONAL BASES
• ADAPTATION AND MITIGATION
OPTIONS IDENTIFIED AND
CODIFIED
• INTEGRATED MANAGEMENT ON A
REGIONAL BASIS