Changing Level of the Ocean: TheImpact of Sea Level Change

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“Of all the ongoing and expectedchanges from global warming. . .the increase in the volume of theoceans and accompanying rise inthe level of the sea will be themost immediate, the mostcertain, the most widespread,and the most economicallyvisible in its effects.” Pilkey andYoung, The Rising Sea, 2009

“…sea level has been rising atleast 50% faster…thanprojected by the IPCC 2007AR4 Report.” Ramsdorf, 2012

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Major Information Sources• IPCC (Intergovernmental Panel on Climate Change)• National Academies (Science and Engineering)• U.S. Global Change Research Program (13 Fed.

Agencies)• CA Climate Change Center (core research at Scripps

and UCB) and Climate Action Team (state agencies)• National Science Foundation• National Center for Atmospheric Research• Climate peer-reviewed literature (lots!)• World Bank• U.S. Army Corps of Engineers• UCSD-Scripps Coastal Data Information Program

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Tem

pera

ture

Weather

“Weather” vs. “Climate”

Time

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Why So Much Concern Now?• Identified as most serious possible “abrupt” change by

IPCC in 2007 and more data showing that’s true• Rate of rise has accelerated from ~1.7 mm/yr (0.07”)

during 20th century to 3.2 mm/yr (0.13”) over the past 20years and up to 3.2-3.6 today

• This rate accelerating and expected to continue withwarming

• Related to SLR are:– Storm surges– Extreme high (“king) tides and waves– Coastal development

• CA study (SFSU, 2011) shows $100B property at risk for1m SLR and $14B annually needed to protect property

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Impacts of Sea Level Rise: NotJust a Third World Problem

• Biggest problem flooding especially if high tide occurswith storm surge, high waves and El Niño

• Major coastal erosion• Salination of coastal groundwater, estuaries, wetlands• Infrastructure impacts for CA ($100B at max. 55” rise)

– Transportation (highway, rail, shipping, air)– Urbanized areas– Oil, natural gas, electric facilities– Water and wastewater treatment– 104 Harbors/ports

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NASA: Mean SLR = 3.18 +0.6 mm/yr

3.18mm/yr = ~1.3”/decadeover 1992-2012

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From U.S. Army Corps of Engineers, 2011

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Oceans (sea level)• CA coastal sea

level increased 7-8” in last 100years

• Predictions for CAare additional 24-55” rise by 2100*

• 100-year floodevent will becomea 10-year event

*From CA Climate Change Research Center 2009:IPCC 2007 predicted 7 – 23”

55”

24”

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550 - 1100??It’s not a catastrophic end of civilization but majoradaptation to change and life as we know it; Problem isacceleration in rate of change not that earth has never seenthese temps

Last ice age peaked~20,000 years ago,sea levels about 390’(120m) lower

Sea levels 13-20’ (4-6m)higher than today with

temps 5-9ºF higher (~2100prediction)

Reference dates- Today 395 ppm

- IPCC 2007 380 ppm- IPCC 2002 360 ppm

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Expected range for2100 (NAS)

Long-term“modern” average~280 ppm

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From Donaghue, 2011

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Today’s rate of SLR =3.2mm/yr.

~0.1mm/yr

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SL = -120m

SL = current

NOAA graphics14

(~4 ft.)

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From Vermeer and Ramstorf,2009

Sea Level Changeand Rate of

Change Since 1880(red lines observed)

Rate ChangesLast 3K years = ~0.1mm/yr20th Cent. = 1.7 mm/yr1961-2003 = 1.8 mm/yr1993-2003 = 3.1 mm/yr1993-2008 = 3.2-3.6 mm/yr

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Refs. NASA and French Space Agency,2012From Tebaldi et al. (NOAA),

2012 (Note: CA Climate ChangeCenter predicts 0.3-0.45m SLRby 2050)

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ºF

7

11

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CA ClimateChange ResearchCenter (2009)

< 20th Century SLR constant= 3.4 mm/yr/ °C

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IPCC,2007

2012 Updates

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Causes of Sea Level Rise*• Warming expands water (30%)• Glacier/ice sheet melt (70%)

*Percentagescurrently undermuch discussion andchange

1947

2009

South Cascade Glacier,WA – 1960 and 2004(NAS, 2008)

Wilkins Ice Shelf, Antarctica

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Complicating Factors: Building aRealistic Scenario*

• Start with +1m SL increase Add tides and exceptional (King) tides Add wave runup distance and height

(video) and possibility of extreme(rogue, tsunami) waves

Add storm surges

*High water focus

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From Strauss et al., 2012

Mean ~1.5m

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S.M. 2012*High = +6.93’Low = -1.58’Add 3.3’ (1m)New High =10.23’San Fran. =10.1’Balboa = 9.6’(11.3’ actualin 2011)

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*predicted

Average seasonal cycle of mean sea level

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King TidesDefinition: extreme wintertime high tide eventsthat occur as the result of the combinedgravitational forces of the sun and moon.

“Broad” Beach, Malibu: Photos by Laurel Bartels

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LAT Broad Beach 2008

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Graphic from U. Wisc.

D

H

“Sea level rise acts as the baselinereference point to which storm surgeheight is added.” World Bank, 2009

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Wave Runup

http://www.youtube.com/watch?feature=player_detailpage&v=10PfxgbGBMg

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Accelerated erosion of slope toes

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Coastal Flooding 2009-10

“Extreme” Waves

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Crystal Cove Erosion 2009-2010

~5’

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Storm surges add intensity

Graphic buy John F. Henz

El Nino –warmeroceans, morestormintensity

La Nina –cooleroceans, lessstorm intensity

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Graphic from Scripps Coastal Data Information Program, May 201233

Extreme wave height statistics for a 20-year return time (From: aviso.oceanobs.com)

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“… coastal floods may reach locally rare heights more swiftlyin southern California than almost any other (23 studied) area,when considering effects of sea level rise integrated withstorm surge patterns…”From Tebaldi et al. (NOAA), 2012

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“Atmospheric Rivers”

From American Geophysical Union, 2011and Scripps (Jan. 1988 photo)

Oct.2009

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Pacific Institute, 2009

Light blue = current 100-yr floodplainDark blue = modeled with +1.4m(55”) rise by ~2100

LongBeach

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Pacific Institute, 200938

Pacific Institute, 2009

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Pacific Institute, 2009

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S.F. Bay

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San Diego Bay

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Pop.>

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From Strauss et al., 2012

~Maryland ~1.2% of U.S.

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Photo and map from OC Register, March 2011

Recall highest tides with1m SLR added in:2011 = 11.3’2012 = 9.6’Seawalls now at 9’

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+1.5m

Olympia, WA - SLRCurrent “Worst-case” Scenario

(~0.8m)

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World Bank assessment of top25 cities over 100,000

population and countriesimpacted by rising sea levels

(2012)

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Alliance of Small Island States:42 countries, 5% global

population

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Banda Aceh, Indonesia – 2004 Sumatra(island) tsunami

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Mekong Delta, Vietnam

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Mekong River, Vietnam (tidal influenced)

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Mekong River, Cambodia (tidal influenced)

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Tonle Sap (lake) Cambodia(tidal influenced)

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Malé, capital ofMaldives

Shanghai

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Tuvalu – pop. 11,000Tarawa, Kiribati –pop.~30,000

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Other Effects of SLR• Biophysical effects of SLR on coastal regions include:

- Inundation, flood and storm damage- Wetland loss- Erosion- Saltwater intrusion- Coral bleaching from higher sea water temperatures- Ocean productivity changes and species migration.

• Socio-economic impacts- Increased loss of property and coastal habitats- Increased flood risk and potential loss of life- Damage to coastal protection works and otherinfrastructure- Loss of renewable and subsistence resources- Loss of tourism, recreation, and transportationfunctions.57

Adaptation• Disaster preparedness

• Evacuation• Prediction

• Development planning, phased evacuation andbuilding codes

• Engineering upgrades• Define impact zones (floodplains, wave runup,

wetlands)• Assess infrastructure (floodwalls, erosion

prevention, drainage)• Install detection systems(surges, waves)

• Focus international aid (ex. World Bank)• Modernize insurance rates

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Adaptation Actions

World Bank

US Army Corps ofEngineers

State of CAExecutive Order

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Questions?

Hundreds gather inNortheast to protestglobal warming

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Update May2012 = 395

Latestpredictions forrange 550-1100

Sea levels 13-20’ (4-6m)higher than today with

temps 5-9ºF higher(~2100 prediction)

Last ice age ended~10,000 years ago, sealevels about 390’(120m) lower

Possible “Abrupt” Changes (IPCC, 2007)

• Ocean circulation and acidification• Ice cover/glacier ablation Sea level rise (coastal/island inundation)• Hydrologic cycle (floods and droughts)• Ecosystem changes• Rapid release of methane from permafrost and ocean

sediments• Increased risk of species extinctions

Peak SLR rate = 45mm/yr

* “Likely” means 66% chance; ** CA Climate Change Research Center, 2009

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Range 2 – 13.5ºF Range 7 – 23”

CA Prediction** 3-10.5ºF

(1-2.5ºF by2050)

20-55”

(11-18” by2050)

Expected range for2100

Long-term“modern” average~280 ppm