1. 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
jon_boothroyd@uri.edu
2. Southern New England, Long Island, Continental Shelf ~ 26,000 yBP
Map Generated By:
BA Oakley and JC Boothroyd
3. THE LAST NORTH AMERICAN
ICE SHEETS
CORDILLERAN
LAURENTIDE
-
You are
here
After Dyke & Prest, 1987
4. MALASPINA GLACIER – Northeast Gulf of Alaska
-
An Analog “The size of Rhode Island”
5. Oakley, 2011
You are
here
Ice margins modified from:
Dyke and Prest, 1987
Ridge, 2010; Goss, 1993
Smith, 2010
11. Eustatic
Sea-Level
Rise
+
Isostatic
Rebound Laurentide
at Ice Sheet?
Laurentide
2m.100yr-1
Ice Sheet?
Block Island 2m.100yr-1
Antarctic Ice
Antarctic Ice
Sheet?
Sheet? -1
2-5m.100yr
2-5m.100yr-1
Explanation
- 390 ft
Oakley and Boothroyd,
submitted 2011
12. -165 ft
Begin Meltwater Pulse 1B
Post-Glacial
Lake
Atlantic Ocean
13. -130 ft
End Meltwater Pulse 1B
Post-Glacial
Lake
Estuary
Atlantic Ocean
14. When Contemplating Rhode Island
Coastal Geologic Hazards
One Must Consider:
• Extratropical Cyclones (“Nor’easters”)
• Hurricanes (Tropical Cyclones)
• and ……. Sea Level Rise
15. When Contemplating Rhode Island
Coastal Geologic Hazards
Which Give Rise to these Processes:
• Frontal Erosion – from Breaking Waves
and Swash
• Storm-Surge Overwash
• Elevated MHHW into the Future
16. When Contemplating Rhode Island
Coastal Geologic Hazards
The Scale of Processes are:
• 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
17. The Sea May Be Rising Long Term – But…..
Instantaneous Storm Surges
Elevate Sea Level Now
19. Patriots Day Extratropical Storm – April 2007
Newport Tide Gauge
SET UP PREDICTED
http://tidesandcurrents.noaa.gov/
STORM SURGE data_menu.shtml?stn=8452660%20Newport,%20RI&type=Tide+Data
27. Napatree Barrier – Westerly, RI
Little Narragansett Bay
Watch Hill
Hehre and Boothroyd, 2007
28. Napatree Barrier – Shoreline Change Maps
2004 – Sound Side
1939 – Sound Side
1939 – 2004 – Ocean Side
Ocean Side
Hehre and Boothroyd, 2007
29. Tidal
Datums
Newport MHHW = 3.85 ft
3
“Zero” in some NAVD 1988 = 2.05 ft
data sets 2
MSL = 1.74ft New MSL
and on maps
NGVD 1929 = 1.18 ft Old “MSL”
1
MLLW = 0.0 ft
0
-1
Adapted from:
www.ngs.noaa.gov/newsys-cgi-
bin/ngs_opsd.prl?PID=LW0493&E
POCH=1983-2001
30. How High
will the
Water Be? Boothroyd and
Hehre 2008
9.46 Feet Above MHHW
Tidal
Heights
Newport
MHHW = 3.85 ft
MLLW = 0.0 ft Adapted from: www.ngs.noaa.gov/newsys-cgi-
bin/ngs_opsd.prl?PID=LW0493&EPOCH=1983-2001
31. Frequency?
Next Month or
Next Year
Tropical Storm
Irene Aug 2011
Adapted from
NOAA;
USACE 1988;
Hehre 2007
35. HEIGHT NOW
Adapted from:
http://tidesandcurrents.noaa.gov/sltrends/
sltrends_station.shtml?stnid=8452660%20Newport,%20RI
Boothroyd 2011
36. Observed Global Sea Level Rise ... Accelerating
IPCC
18 cm rise since 1900 2001
Current rate:
estimate
3.3 cm per decade
Rahmstorf, Cazenave, Church, Hansen, Keeling, Parker and Somerville (Science 2007)
37. Global Sea Level Linked to Global Temperature
Projection of Sea-Level Rise 1990 - 2100
Using IPCC 2007 Temperature Projections
Extreme
Projection
IPCC 2007
Vermeer and Rahmstorf, 2009,
PNAS, v106, p 21537-21532
38. Height above NOW
New
Estimate
Low
3.3 ft Range 100 cm
1.1 ft 35 cm
2050
39. Height above NOW
New 140 cm
4.6 ft
Estimate
Mid
1.4 ft 42 cm
2050
40. 6.2 ft Height above NOW 190 cm
New Estimate High Range
1.6 ft 50 cm
2050