U.S. Department of the InteriorU.S. Geological Survey

Dr. Virginia BurkettUSGS Chief Scientist for Global Change Research

Climate Change and Regional

Coastal Hazards

OutlineOutlineI.I. Global and regional climate trends Global and regional climate trends

and projectionsand projections

II.II. Key climate change drivers in coastal Key climate change drivers in coastal systemssystems

III.III. Effects on coastal hazards and Effects on coastal hazards and infrastructure infrastructure

Small Sea Changes: BIG Infrastructure ImpactsHouston, TexasNovember 13, 2009

379 ppm379 ppm

Temperature and C02 record from Vostok, Antarctica ice core projectTemperature and C02 record from Vostok, Antarctica ice core project

Lower, red line = temperature Lower, red line = temperature Upper, blue line = C02 levelUpper, blue line = C02 level

(Petit et al. 1999)

Past 400,000 Years:

-55

-50

-45

-40

-35

-30

-25

05101520

Tem

pera

ture

in C

entra

l Gre

enla

nd (C

)

Thousands of years before present

10º C increase in several decades at end of Younger Dryas interval (YD)

(based on Alley, 2000)

warmer

colder

YD

Past 20,000 Years:

©IPC

C W

G1, 2007

Past 10,000 Years:

© IPCC, 2007

Atmospheric ChangeAtmospheric Change• C02 increased 35%, methane increased 150% compared to pre-industrial levels (attributed to fossil fuel use & land use change)

Past 100 years:

• Global average temperature increased 0.74 ºC over past 100 yrs, 0.65 ºC over past 50 years

Change in ice and snow:Change in ice and snow:• Arctic summer sea ice has shrunk

7.4% per decade since 1978 • Less snow at low altitudes and

earlier spring runoff• Mountain glaciers declined globally

©IPC

C, 2007

Glacier Mass

March-April Snow Cover in the Northern Hemisphere

© IPCC, 2007

• Ocean temperature increased from surface down to at least 3000 m

• Increase in N. Atlantic hurricane activity • Increase in ocean acidity

Geographic Variability in the Rate of

Sea Level Rise (1955 to 2003)

© IPCC, 2007

Ocean change:Ocean change:

(acceleration or natural variability?)

• Global sea level rise - 1.7 mm/yr during 20th century- 3.1 mm/yr during 1993-2003

Projected Projected future future changes changes • Warming is expected to be about 0.4º C during next

20 years – with greatest warming over land and at high latitudes in the northern hemisphere

• GHG emissions at or above current rates would induce other changes in 21st century climate that are very likely to be larger than those observed over the past century

• Very likely that heat waves, heat extremes and heavy precipitation events will increase

• More intense tropical storms • Accelerated sea level rise

© IPCC, 2007

Climate Change Drivers in Coastal Systems

Church, J.A. and White, N.J. (2006) http://maps.grida.no/go/graphic/trends-in-sea-level-1870-2006

Global Mean Sea Level Rise, 1870-2006

Other causes of subsidence in Gulf Coast region:

NORMAL LAKE 1.0 FT LEVEL

SPH DESIGN ELEV 11.5 FT17.5 FT

HURRICANEPROTECTION LEVEE& FLOODWALL

AVG ANNUAL HIGHWATER 14 FT18 FT PROJECT FLOWLINE23 FT

FLOODWALL ALONGMISSISSIPPI RIVER

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Net Effect on New Orleans Elevation

“Relative sea level rise” is a combination of eustacy and regional or local land surface elevation change generally

associated with tectonism, isostacy, or subsidence

2.14 mm/yr

6.5 mm/yr

9.85 mm/yr

NOAA Historical Tide Gauge Data (1900-2000)

As the oceans warm and land ice declines, sea level rise is expected to accelerate

(IPCC, WGI, 2007)

As the oceans warm and land ice declines, sea level rise is expected to accelerate

The Greenland Ice Sheet Dominates

Land Ice in the Arctic

Over the past two decades, the melt area on the Greenland ice

sheet has increased on average by about

0.7%/year (or about 20% from 1979 to

2005).

The Greenland Ice Sheet Dominates

Land Ice in the Arctic

Over the past two decades, the melt area on the Greenland ice

sheet has increased on average by about

0.7%/year (or about 20% from 1979 to

2005). Photo Source: Business Week 2004

(USG

CR

P 20

09)

Melt area of the Greenland ice sheet increased on average by 0.7% per yr

between 1979 and 2005.

With sustained warming of 4º-13ºF over central Greenland most of the

Greenland Ice Sheet will melt, raising sea level 6-7 m.

(USG

CR

P 2009)

Mean Sea

Level (Meters)

MeltwaterPulses

Onset of Holocene Delta Formation

present sea level

Sea-level rise influences coastal ecosystems through several mechanisms

LA

FL

SC

• Increases salinity • Alters plant community structure & productivity• Alters fish, shellfish & wildlife populations

MD

Inland Expansion of Oyster LeasesBarataria Basin, LA 1947, 1959, 1975

(Van Sickle, Barrett, Gulick and Ford, 1976)

Sea-level rise influences coastal ecosystems through several mechanisms

• Increases salinity • Alters plant community structure & productivity• Alters fish, shellfish & wildlife populations• Accelerates shoreline erosion• Makes restoration more difficult & expensive• Enhances infilling of estuaries with coastal sediment• Amplifies effects of other stresses, such as

navigation channels• Increases storm surge & normal tide levels

Increased temperature of the sea surface affects both the volumeof the ocean (sea level) and the propensity for hurricanes.

Map of the cumulative tracks of all tropical cyclones during the1985–2005 time period.

Atlantic MDR

Gulf of Mexico

Upper graph: Bell et al., 2007Lower Graph: National Climate Data Center, Smith and Reynolds, 2004

Sea Surface Temperature is expected to continue to increase in the Atlantic Main Development Region for Hurricanes and in the Central Gulf of Mexico

Blue lines = historical storm tracks

Increased storm intensity amplifies the effects of sea-level rise

Low-lying coastal communities may be inundated by rising sea level and coastal erosion will accelerate if storms increase in intensity.

Dauphin Island, AL

Source: United Houma Nation

Source: Isle De Jean Charles band

Source: United Houma Nation

Historical photo source: United Houma Nation

Isle de Jean Charles tribe pursues relocating from island (Houma Courier, Sept. 22, 2009)

HOUMA — Members of a local American Indian tribe are making a new push for government help moving away from their ancestral home on a remoteTerrebonne Parish island.Related Links:Council to take up potential relocation of islanders In search of higher ground Island Road repairs will cost millions Island residents insist on staying put Federal hurricane-recovery dollars may be available to help pay for a mass relocation from Isle de Jean Charles to higher ground, parish and state officials saidAnd the group’s leader said he wants to seize the chance before the island’s residents disperse on their own and lose their community.Since Hurricane Lili in 2002, families have trickled from the island. Now an estimated two dozen families remainon the one-and-one-half-mile sliver of land.Albert Naquin chief of the Band of Biloxi-Chitimacha

Examples of impacts on oil and gas operations

Port Fourchon, LA

1. Onshore oil and gas facilities could be more difficult to permit, construct, and maintain (due to stresses on coasts associated with climate change and sea level rise).

Examples of impacts on oil and gas operations

1. Onshore oil and gas facilities could be more difficult to permit, construct, and maintain (due to stresses on coasts associated with climate change and sea level rise).

2. Sea level rise and/or increase in tropical storm intensity will affect oil and gas infrastructure (offshore and onshore)

Rig damage during Hurricane Lilli

off the LA coast, Eugene Island area

3. Surface transportation systems that are essential to coastal onshore and offshore oil and gas development may be impassable more frequently or permanently.

Net Effect of Relative Sea Level Rise in Lafourche Parish

LA Highway 1, less than a foot above sea level, is a key highway that supports the offshore oil and gas industry in the Central Gulf Coast Region

4. Erosion of coastal barriers will affect wave energy and storm surge in oil and gas fields that were developed under more protected conditions.

(Stone et al. 2003)

Terrebonne BayChange in Wave Height

8’-10’ Change in Storm Surge, 1950-1990

(Stone et al. 2003)

Red dots are oilfield platforms in Terrebonne Bay, LA and adjacent

nearshore waters

East Timbalier

island

Terrebonne Bay

5. High-energy waves can erode sediments, exposing a pipeline to stress levels it was not designed to withstand, causing a fracture. An exposed offshore pipeline also could be vulnerable to lateral and vertical displacement during storms, exposure to vessel traffic and fishing trawls, or rupture by currents.

(Seismic profile from Dave Twitchell, USGS Woods Hole)

Terrebonne Bay

Pits scoured in flat-lying deposits seaward of the Chandeleur Islands

Erosional Features in Chandeleur Island Bathymetry

NAVD88 Elevation (m)

0.5 -15

AB

A

B

Pits Linear troughs

(Dave Twitchell, USGS Woods Hole)

Distribution of erosional pits

Pit dimensionsmin: 7.1 mmax: 339.8 mmean: 78.5 m

(Dave Twitchell, USGS Woods Hole)

6. Permafrost decline is already affecting oil and gas facilities in coastal Alaska.

The U.S. Bureau of Land Management has identified about 30 old oil exploration wells that will soon be in danger of erosion. BLM has plans to plug these wells to prevent contamination.

Stan Porhola photo (BLM)

J.W. Dalton wellsite, National Petroleum Reserve AK

September - 2005

Susan Flores photo (BLM)

September - 2004

7. Hazards associated with the formation of thermokarstlakes in the coastal zone and the stability of shelf sediments due to thawing ice in sediments and the release of gas from clathrates.

Accelerated land loss and formation of thermokarst lakes

along Alaska Beaufort Sea coast

John (Lyle) Mars, Dave Houseknecht, & Chris Garrity, USGS

8. Navigation routes through the Northwest and Northeast Passages may be opened, even if ice simply thins to the point that shipping lanes can be mechanically maintained by icebreakers. Longer ice free season for exploration and development.

Arctic Summer Sea Icesource: NASA GSFC

1979

2007

What can be done to reduce adverse impacts?

mitigation• Reduction of greenhouse gas

emissions or enhancement of carbon sequestration

adaptation• Purposeful actions taken to reduce

undesirable effects or enhance positive effects of climate change