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CLIMATE CHANGE,
COASTAL GEOLOGIC HAZARDS and
SEA-LEVEL RISE
URI Climate Change Symposium 18 November 2011
Jon C. Boothroyd
Rhode Island State Geologist, Research Professor Emeritus – Quaternary Geology
------------- Rhode Island Geological Survey and Department of Geosciences
College of the Environment and Life Sciences University of Rhode Island
[email protected]
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Map Generated By: BA Oakley and JC Boothroyd
Southern New England, Long Island, Continental Shelf ~ 26,000 yBP
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-
THE LAST NORTH AMERICAN ICE SHEETS
After Dyke & Prest, 1987
LAURENTIDE
CORDILLERAN
You are here
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MALASPINA GLACIER – Northeast Gulf of Alaska
An Analog “The size of Rhode Island”
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You are here
Oakley, 2011
Ice margins modified from: Dyke and Prest, 1987 Ridge, 2010; Goss, 1993 Smith, 2010
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Oakley, 2011
Ice margins modified from: Dyke and Prest, 1987 Ridge, 2010; Goss, 1993 Smith, 2010
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Charlestown Moraine
Ice margins modified from: Dyke and Prest, 1987 Ridge, 2010; Goss, 1993 Smith, 2010
Oakley, 2011
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Oakley, 2011
Ice margins modified from: Dyke and Prest, 1987 Ridge, 2010; Goss, 1993 Smith, 2010
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Oakley, 2011
Ice margins modified from: Dyke and Prest, 1987 Ridge, 2010; Goss, 1993 Smith, 2010
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Oakley, 2011
Ice margins modified from: Dyke and Prest, 1987 Ridge, 2010; Goss, 1993 Smith, 2010
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Eustatic Sea-Level
Rise +
Isostatic Rebound
at Block Island
Antarctic Ice Sheet?
2-5m.100yr-1
Laurentide Ice Sheet? 2m.100yr-1 Laurentide Ice Sheet? 2m.100yr-1
Antarctic Ice Sheet?
2-5m.100yr-1
Explanation
Oakley and Boothroyd, submitted 2011
- 390 ft
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Post-Glacial Lake
Atlantic Ocean
Begin Meltwater Pulse 1B
-165 ft
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Post-Glacial Lake
Estuary
Atlantic Ocean
End Meltwater Pulse 1B
-130 ft
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When Contemplating Rhode Island
Coastal Geologic Hazards
• Extratropical Cyclones (“Nor’easters”)
• Hurricanes (Tropical Cyclones)
• and ……. Sea Level Rise
One Must Consider:
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• Frontal Erosion – from Breaking Waves and Swash
• Storm-Surge Overwash
• Elevated MHHW into the Future
Which Give Rise to these Processes:
When Contemplating Rhode Island
Coastal Geologic Hazards
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• Breaking Waves – 3 to 10+ feet at shoreline
• Storm-Surge Overwash – 1 to 10+ feet water depth across shore zone
• Sea-Level Rise – 0.14 inches per year at present
The Scale of Processes are:
When Contemplating Rhode Island
Coastal Geologic Hazards
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The Sea May Be Rising Long Term – But….. Instantaneous Storm Surges
Elevate Sea Level Now
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Narragansett Pier Seawall – Patriots Day 2007
WPRI.com 16 apr 2007
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Patriots Day Extratropical Storm – April 2007 Newport Tide Gauge
SET UP PREDICTED
http://tidesandcurrents.noaa.gov/ data_menu.shtml?stn=8452660%20Newport,%20RI&type=Tide+Data STORM SURGE
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RE Hehre
Overwash - Browning Cottages
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BA Oakley
Frontal Erosion - Browning Cottages
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Frontal Erosion 1939-2006 - Browning Cottages
1939
2006
2011
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RE Hehre
Charlestown Beach
Overwash
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Aug 1991
Charlestown Beach – Hurricane Bob 1991 Washover Fan Deposition
Removal is a Bad Idea ……. Barriers Naturally Retreat
Landward and Upward
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Watch Hill – Hurricane Carol, 1954
Providence Journal, 1954
But… Sometimes there is no alternative
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A General Coastal Barrier Model for Rhode Island
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Napatree Barrier – Westerly, RI
Hehre and Boothroyd, 2007
Little Narragansett Bay
Watch Hill
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Napatree Barrier – Shoreline Change Maps
1939 – Ocean Side
1939 – Sound Side
2004 – Ocean Side
2004 – Sound Side
Hehre and Boothroyd, 2007
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2
Tidal Datums Newport
Old “MSL” New MSL
Adapted from: www.ngs.noaa.gov/newsys-cgi-
bin/ngs_opsd.prl?PID=LW0493&EPOCH=1983-2001
“Zero” in some data sets
and on maps
-1
0
1
3
MLLW = 0.0 ft
MHHW = 3.85 ft
NAVD 1988 = 2.05 ft
MSL = 1.74ft
NGVD 1929 = 1.18 ft
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9.46 Feet Above MHHW
Tidal Heights Newport
How High will the
Water Be? Boothroyd and
Hehre 2008
Adapted from: www.ngs.noaa.gov/newsys-cgi-bin/ngs_opsd.prl?PID=LW0493&EPOCH=1983-2001
MHHW = 3.85 ft
MLLW = 0.0 ft
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Adapted from NOAA;
USACE 1988; Hehre 2007
Frequency? Next Month or
Next Year
Tropical Storm Irene Aug 2011
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Lastly, Climate Change
and the Future Shore Zone
of Rhode Island
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Greenland Outlet Glaciers Change from Polythermal to Warm Based
A Key to Future Sea-Level Rise
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Adapted from: http://tidesandcurrents.noaa.gov/sltrends/
sltrends_station.shtml?stnid=8452660%20Newport,%20RI
HEIGHT NOW
Boothroyd 2011
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18 cm rise since 1900 Current rate:
3.3 cm per decade
Observed Global Sea Level Rise ... Accelerating
Rahmstorf, Cazenave, Church, Hansen, Keeling, Parker and Somerville (Science 2007)
IPCC 2001
estimate
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Projection of Sea-Level Rise 1990 - 2100 Using IPCC 2007 Temperature Projections
Vermeer and Rahmstorf, 2009, PNAS, v106, p 21537-21532
Global Sea Level Linked to Global Temperature
Extreme Projection
IPCC 2007
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New Estimate
Low Range
2050
100 cm 3.3 ft
35 cm 1.1 ft
Height above NOW
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New Estimate
Mid
2050
42 cm
4.6 ft 140 cm
Height above NOW
1.4 ft
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New Estimate High Range
2050
50 cm
190 cm 6.2 ft Height above NOW
1.6 ft
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Misquamicut Headland – 100 Yr Hurricane Surge
Present Outdated
Flood Map
+ 3 feet Sea Level Rise
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Providence Journal, 1938
Misquamicut – US 1A – Westerly 1938 Hurricane - Debris Swath
Barrier Debris Swath after Sea-Level Rise
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Ninigret – Green Hill Lagoons
2003 – 2004 Orthophoto
Today
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1938 Storm Surge + SL Rise after 1938 11 ft above MHHW
Ninigret – Green Hill Lagoons
Today
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1938 Storm Surge + SL Rise 11 ft above MHHW
Ninigret – Green Hill Lagoons
Today
Frosty Drew
Foster Cove Area
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Ninigret – Green Hill Lagoons
2003 – 2004 Orthophoto
Today
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Ninigret – Green Hill Lagoons 2100 Inundation – 5 ft
200 ft Barrier Migration
Projected
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Ninigret – Green Hill Lagoons 2100 Inundation – 5 ft
200 ft Barrier Migration
Projected
Foster Cove Area
Frosty Drew
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Wickford Marketplace – In-Place Inundation “The Bathtub Ring”
10 Sept 2010 Teresa Crean
Today
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End of Presentation
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THE HOCKEY STICK
Moberg et al, 2005
Medieval Warm Period Little Ice Age
Temp lags CO2
The Message