Deriving the Eustatic Sea Level Component in the Kattaegatt Sea
Environment Sea Level Rise - الصفحات الشخصية | الجامعة...
Transcript of Environment Sea Level Rise - الصفحات الشخصية | الجامعة...
Coastal & MarineEnvironment
4Chapter
Sea Level Rise
Mazen AbualtayefAssistant Prof., IUG, Palestine
Coastal & MarineEnvironment
4Chapter
Sea Level Rise is defined as a mean
rise in sea level
What is Sea Level Rise?
Coastal & MarineEnvironment
4Chapter
What happens to the island?
When sea level rises……
How does the slope of the land influence the loss of shoreline?
Gentle slopeSteeper slope
west east
Island
Coastal & MarineEnvironment
4Chapter present sea level
Tide gauge
increase due to climate warming
decrease due to climate cooling
Coastal & MarineEnvironment
4Chapter present sea level
Tide gauge
decrease due to land rising
increase due to land subsidence
Coastal & MarineEnvironment
4Chapter present sea level
Tide gauge
What about an area with excessive sediment input, does sea level change?
Sea level remains constant, the container holding the water (oceans) is very large.
Coastal & MarineEnvironment
4Chapter
• Climate warmingGlacial ice melts and seawater volume expands
• Climate coolingMore glacial ice forms and seawater volume
contracts
• Land rebound (rising)Rebound of land due to former glaciation and
removed
• Land subsidence (sinking)Withdrawal of groundwater or petroleum
Relative Sea Level Change
Coastal & MarineEnvironment
4Chapter
Global Warming Processes
(Source:http://www.cotf.edu/ete/modules/climate/GCclimate1.html)
(Source:http://library.thinkquest.org/C0051
37F/automobile_traffic_pollution.jpg)
• This process can
lead to an increase in
global temperature
when greenhouse
gases are added to
the atmosphere
• An increase in global
temperature can result
in sea level rise due to
the melting of glaciers
The Greenhouse Effect
is a process that
makes the Earth
inhabitable
(Source: NASA)
Coastal & MarineEnvironment
4Chapter Ice and snow profoundly affect our
climate. During the Northern Hemisphere
winter, they blanket up to 16% of the Earth’s
surface with a bright covering that reflects
much of the Sun’s radiant energy back to
space. During the Southern Hemisphere
winter, they cover about half this area.
An expected consequence of global warming
is a decrease in the Earth’s snow and ice
cover, which would increase the global
absorption of solar radiation and, in the event
of a significant melting of land ice, increase
sea level.
Background
Iceberg
Coastal & MarineEnvironment
4Chapter
Ice sheets and glaciers are important
reservoirs for fresh water. Approximately 75%
of the world’s fresh water is stored in ice, the
remainder being stored underground or in
lakes, rivers and streams. Of the 75% in ice,
approximately 91% is held in the Antarctic ice
sheet, 8% in the Greenland ice sheet, and the
remaining 1% in mountain glaciers.
Background
Coastal & MarineEnvironment
4Chapter
Over the past century, sea level has slowly been
rising. This is in part due to the expansion of
ocean water as it warms and in part due to the
addition of water to the oceans through either the
melting or the calving off of icebergs from the
world’s land ice. A vast majority of individual
mountain glaciers and ice caps are known to have
been retreating, some very rapidly, and their melt
and consequent runoff contribute to sea level rise.
Although scientific evidence is increasing that on
balance, both the Greenland and Antarctic ice
sheets are shrinking, it is still uncertain what
impact this will have on the world’s population. If
all the ice melted or otherwise entered into the
oceans, global sea level would rise by
approximately 70 meters.
Background
Coastal & MarineEnvironment
4Chapter
Average Rate ~ 1.8 mm/year
0.8 mm/year
2.0 mm/year
Global Mean Sea Level from Tidal Gauge observations around world
Coastal & MarineEnvironment
4Chapter
100 0.0740.018
50 0.1280.026
Warmest 12 years:1998,2005,2003,2002,2004,2006, 2001,1997,1995,1999,1990,2000
Period Rate
Years /decade
Global mean temperatures
Coastal & MarineEnvironment
4Chapter
Contribution to Sea Level by
Thermal Expansion
-15
-10
-5
0
5
10
15
20
1960 1970 1980 1990 2000
DM
SL
(m
m)
Year
Rate = 0.4 mm/year (1955-2004)
Coastal & MarineEnvironment
4Chapter
Contribution to Sea Level by
Mountain Glaciers
0
5
10
15
20
25
1960 1970 1980 1990 2000 2010
DM
SL (
mm
)
Year
1961-2003: 0.5 mm/year
0
5
10
15
20
25
1960 1970 1980 1990 2000 2010
DMS
L (
mm
)
Year
Coastal & MarineEnvironment
4Chapter
Sea Level Budget (IPCC-2007, mm/year)
Thermal Expansion
Mountain Glaciers
Greenland Ice Melt
Antarctic Ice Melt
Land Water Storage
Total of Observed Contributions
+
+
+
=
Observed Sea Level Change
1.6 ± 0.5
0.8 ± 0.2
0.2 ± 0.1
0.2 ± 0.3
?
2.8 ± 0.7
1993-2003 1961-2003
0.4 ± 0.1
0.5 ± 0.2
0.1 ± 0.1
0.1 ± 0.4
?
1.1 ± 0.5
3.1 ± 0.7 1.8 ± 0.5
Coastal & MarineEnvironment
4Chapter
1. According to observations and
measurements, average global
increase in sea level is 1-2
mm/year.
2. Mean Sea Level is projected to
rise by 0.18 m to 0.59 m by 2100,
But with Significant Regional
Variations, IPCC 2007)
Coastal & MarineEnvironment
4Chapter
Factors affecting sea level
Not directly climate related:
• Tides – Periodic changes due to changing orbital motions of earth & moon
• Storm surges - Atmospheric effects
• inverse barometer, tropical storm/hurricane surges
• Wind-stress driven surge
Directly climate related:
• Isostatic – Vertical movement of land
• Eustatic – changes of total sea water mass
• Steric – Thermal expansion of water volume
Coastal & MarineEnvironment
4Chapter
Factors affecting sea level:
Astronomical tides
0 5 10 15 20 25Time (days)
-2
-1
0
1
2
Sea
leve
l
Coastal & MarineEnvironment
4Chapter
Factors affecting sea level:
Atmospheric variations
Inverse barometer effect
The inverse response of sea level to changes in atmospheric pressure.
A static reduction of 1.005 mb in atmospheric pressure will cause a stationary rise of 1 cm in sea level
1000mb
980mb
20cm
Low Atmospheric Pressure
Coastal & MarineEnvironment
4Chapter
Factors affecting sea level:
Storm surges
1. A deep centre of low pressure situated over
Scandinavia produces northerly winds.
2. Wind stress forces surface waters into the “bottle-
neck” of the English Channel.
3. Flow is restricted by the Straits of Dover and sea
levels rise along the adjacent coasts of East Anglia
and the Netherlands.
4. Other key ingredients include high Spring tides and
on-shore winds.
Coastal & MarineEnvironment
4Chapter
Factors affecting sea level:
Isostatic changes
Isostatic changes = vertical land movements
Examples:
• Stockholm, Sweden (Glacial Isostatic Adjustment).
• Nezugaseki, Japan (abrupt jump in sea level
record following earthquake in 1964).
• Fort Phrachula Bangkok, Thailand (sea level rise
due to increased groundwater extraction since
about 1960).
• Manila, Philippines (recent deposit from river
discharges and reclamation works).
• Honolulu, Hawaii (a site in the PGR 'far field'
without evident strong tectonic signals on
timescales comparable to the length of the tide
gauge record and with secular trend 1.5 mm/year).
Coastal & MarineEnvironment
4Chapter
Factors affecting sea level:
Eustatic changes
Eustatic changes = volumetric (mass) changes
Glaciers, ice-caps or ice-sheets:• Gain mass by accumulation of snow (snowfall and
deposition by wind-drift), which is gradually transformed to ice.
• Lose mass (ablation) mainly by melting at the surface or base with subsequent runoff or evaporation of the melt water.
• Net accumulation occurs at higher altitude.• Net ablation at lower altitude.• The mass balance for an individual body of ice is
usually expressed as the rate of change of the equivalent volume of liquid water, in m3/yr; the mass balance is zero for a steady state.
Coastal & MarineEnvironment
4Chapter
Factors affecting sea level:
Steric rise• As oceans warm, density decreases and thus even at
constant mass the volume of the ocean increases.
• Thermal expansion (or steric sea level rise) occurs
at all ocean temperatures.
• Water at higher temperature or under greater
pressure (at greater depth) expands more for a given
heat input. Therefore, the global average expansion
is affected by the distribution of heat within the ocean.
• Salinity changes within the ocean also have a
significant impact on the local density and thus local
sea level, but have little effect on global average sea
level change.
• The rate of climate change depends strongly on the
rate at which heat is removed from the ocean surface
layers into the ocean interior – if heat is taken up
more readily, climate change is retarded but sea level
rises more rapidly.
Coastal & MarineEnvironment
4Chapter
Δh (t) = X (t) + g (t) + G (t) + A (t) + I (t) + p (t) + s (t)
The components of MSL rise are due to:
X is the thermal expansion (steric rise);
g is the loss of mass of glaciers and ice caps (eustatic rise);
G is the loss of mass of the Greenland ice sheet due to current climate change
(eustatic rise);
A is the loss of mass of the Antarctic ice sheet due to current climate change
(eustatic rise);
I is the loss of mass of the Greenland and Antarctic ice sheets due to the ongoing
adjustment to past climate change (eustatic rise);
p is the runoff from thawing of permafrost (eustatic rise);
s is the deposition of sediment on the ocean floor.
Coastal & MarineEnvironment
4Chapter
Sea-Level Rise Impacts
• Periodic flooding and permanent inundation – “a whole new floodplain”
• Coastal squeeze– Coastal ecosystem migration halted by
engineered shoreline defenses
• Shoreline recession– Inland migration of natural shorelines
• Ecosystem transformation – Shift in aereal extent of coastal habitats
and habitat relationships
• Saltwater intrusion– Inland migration of salt/fresh surface and
groundwater interface
Coastal & MarineEnvironment
4Chapter
Coastal erosion and accretion
• 1 cm rise in MSL erodes approx 1m horizontally of beach
• Sea level rise has a profound effect on rate of sedimentation
• Varying of sedimentation rates -> changing vegetation zones e.g. growth/shrinkage of marshes
• Storm surges force large quantities of shore-face sediments through inlets -> create tidal deltas/barriers
1m 0.1
Coastal & MarineEnvironment
4Chapter
Vulnerable populated regions
Large Coastal Cities:Populations >8 million
(over 50% of US population live in coastal areas, >110 million)
Highly populated Delta regions:Vulnerable to MSL rise
http://www.survas.mdx.ac.uk
Coastal & MarineEnvironment
4Chapter
Flood and storm damage
• Coastal region more susceptible to storm surges, flooding, beach/coastal erosion=> disruption of activities; danger to life; infrastructure damage
• 1 m rise in MSL would enable a 15-year storm to flood areas that today are only flooded by 100-year storms
• Urban flooding: contaminated water supply; drainage/waste systems overwhelmed
• Flood damages would increase 36-58% for a 30-cm rise in sea level, and increase 102-200% for sea level rise greater than 90 cm
Source: National Hurricane Service
Coastal & MarineEnvironment
4Chapter
Increased salinity in estuaries• Saltwater will penetrate farther inland and
upstream in estuaries i.e. estuarine salt wedge.
• Higher salinity impairs both surface water and human groundwater water supply
• Saltwater intrusion would also harm ecosystems:• aquatic plants and animals e.g. salt marshes,
mangroves• Higher salinity has been found to decrease
seed germination• Flooded agricultural land takes a long time to
recover from saline water
• Decline of coastal commercial fisheries e.g. Salinity intrusion has already been cited as primary reason for reduced oyster harvests in Delaware and Chesapeake Bays in the USA
Coastal & MarineEnvironment
4Chapter
Potential Impacts on the
Natural Environment
Loss of habitat such as coral reefs
and wetlands may have significant
impacts in the coastal zone
Coastal & MarineEnvironment
4Chapter
Potential Impacts on Humans
and the Built Environment
(Source: www.jri.org.uk/brief/ climatechange.htm)
As coastal
populations
increase,
vulnerability of
those populations
to sea level rise
increases as well.
7 million people live
below the 1 meter
contour line in
Bangladesh.
Coastal & MarineEnvironment
4Chapter
Sea-Level Rise Policy
Continuum
Coastal County or Municipal Government
Coastal & MarineEnvironment
4Chapter
To ensure adequate protection of the
built environment through soft and hard
shoreline stabilization that seeks to
maintain a static shoreline position
within the City.
Protection
Coastal & MarineEnvironment
4Chapter
Seawall - Kailua-Kona, HI
Motorway Dike - Netherlands Living Shorelines
Hard Stabilization
Living Shorelines
Soft Stabilization
Coastal & MarineEnvironment
4Chapter
Protection Considerations
Advantages Disadvantages
• Protects important private
and public infrastructure
• Creates investor certainty
• Can be used with other
strategies
• Requires long-term
maintenance
• May be unsustainable
(depending on SLR rates)
• Ecologically problematic
• Loss of sandy beaches,
coastal squeeze
Coastal & MarineEnvironment
4Chapter
Accommodation
To accommodate increasing sea
levels and the additional flooding
that will result by adapting the built
environment and enhancing the
resiliency of the natural environment
where it is economically and
ecologically practicable to do so.
Coastal & MarineEnvironment
4Chapter
Floating Bridge - Seattle, WA
Multi-family floating canal houses -
Scheepstimmermanstraat, Amsterdam House on stilts – New Orleans, LA
Floating House – Brad Pitt’s Make
it Right Foundation, New Orleans,
LA
Coastal & MarineEnvironment
4Chapter
Accommodation Considerations
Advantages Disadvantages
• Allows development to
proceed in transition
areas and where SLR is
uncertain – threat of sea
level rise is prolonged
• Minimizes damage
• Increases vulnerability
• Alters the
characteristics of
shorelines
• Short-term solutions that eventually lead to
protection or managed
relocation strategy
Prolonged: مطول
Vulnerability: قابلية اإلصابة
Coastal & MarineEnvironment
4Chapter
To Reduce vulnerability in the built
environment and preserve coastal
ecosystems through changes in land
use and the orderly abandonment
and /or landward relocation of
structures and associated
infrastructure
Managed Relocation
Coastal & MarineEnvironment
4Chapter
Managed Relocation Considerations
Advantages Disadvantages
• Promotes ecosystem
migration
• Minimizes threats to
humans
• Financially sustainable
in the long-term
– Potentially expensive
for areas that are
significantly
developed
• Politically problematic to
implement
• May be subject to legal
challenge
• Relocation issues
Coastal & MarineEnvironment
4Chapter
Scenarios
by
Projected
SLR for the
Nile Delta
CASE STUDY
Coastal & MarineEnvironment
4Chapter
Trend and Accelerated Sea Level Rise
(ASLR) Measured Along the Nile Delta
Coast.
(CoRI-2007), First Scenario
Sea Level
Rise (Cm)
2100
Sea Level
Rise (Cm)
2075
Sea Level
Rise (Cm)
2050
Sea Level
Rise (Cm)
2025
Average
Annual
ASLT
(Cm)
Station
16.012.08.04.00.16Alex.
23.016.2511.55.750.23Al-Burullus
53.039.7526.513.250.53Port Said
Coastal & MarineEnvironment
4Chapter
Expected SLR Till 2100 by Projected
Increase in Air Temperature
(B1 Scenario (
2100207520502025Year
1.81.81.30.9
Temperature
(ºC)
28 cm27 cm16.0 cm 7.0 cm
ASLR at
Alexandria
35.0 cm32.25 cm19.5 cm8.75 cm
ASLR at
Al-Burullus
72.5 cm64.3 cm39.5 cm18.12 cm
ASLR at
Port Said
Coastal & MarineEnvironment
4Chapter
Total affected area and its percentage to the
Nile Delta area According to CoRI
measurements till 2100
(Without Mohammed Ali wall and zero level for lakes borders)
2100207520502025Year
832.7748.4691.8633.8
Total Area
Affected
(km2)
3.333.02.572.53
Total % of
the Nile
Delta Area
Coastal & MarineEnvironment
4Chapter
Total affected area and its percentage to the
Nile Delta Area According to CoRI
measurements till 2100
(With Mohammed Ali wall lakes borders)
2100207520502025Year
183.8139.2134.093.68
Total Area
Affected
(km2)
0.740.560.540.37
Total % of
the Nile
Delta Area
Coastal & MarineEnvironment
4Chapter
Muhammed Ali Sea Wall Protected
Cultivated Low Lands (1.5m - 2.5m
Below Sea Level)
Coastal & MarineEnvironment
4Chapter
Abu Quir Bay
Low Lands (1.5 – 2.5 m Below Sea Level)
Protected By Muhammed Ali Sea Wall
Muhammed Ali
Sea Wall
Coastal & MarineEnvironment
4Chapter
Detached Breakwater
Ras Al-Bar Resort Has Gained Lands After the Construction of
Protection Works
Coastal & MarineEnvironment
4Chapter
• Sand dunes systems should be treated as the first defensive line for the Nile Delta.
• Decision makers in coastal governorates as well as concerned ministers should be aware ofthe importance of sand dunes systems and their role in protecting the coastal zone of the Nile Delta.
• Consideration should be paid to coastal lakesas one of the most appropriate adaptive measure against sea level rise.
• Coastal international road should be considered as the second protection measure and studies to support it are urgently required.
• Coastal protection constructions need regular maintenance and should be considered in any coastal zone management plans.
• The northwest coast extended from Alexandria to the Egyptian-Libyan borders is not vulnerable as it has elevation more than 10 m above average sea water level.
Adaptive Process and Policies
Coastal & MarineEnvironment
4Chapter References
1. Global ice and snow presentation, National Aeronautics and Space
Administration, NASA
2. ENVI3410: Coupled Ocean & Atmosphere Climate Dynamics
3. Krystle Macadangdang, LL.M, Melissa Newmons, J.D. Sea Level Rise
Ready.
4. Prof. Ibrahim Elshinnawy, Vulnerability Assessment and Adaptation
Policies for C C Impacts on the Nile Delta Coastal Zones.