patrickbdevaney/mia9 · Datasets at Hugging Face

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Global average sea level will rise by 0.5–1.0 meter
(about 20–40 inches) and possibly more by 2100
(National Research Council, 2010).
WHAT IS POSSIBLE:
Major inputs of water from the melting of high-latitude and high-altitude ice reservoirs could cause a
global average sea-level rise of up to two meters this
century and several more meters over the subsequent
centuries (Rahmstorf, 2010).
II. Sea-Level Rise and Its Effects
on Florida’s Ocean
and Coastal Resources
DRIVER: Sea-Level Rise
Florida’s geology, chemistry, biology, and human population have already been, and will continue to be, profoundly
affected by rising sea levels. For the past few thousand years, sea level around Florida has been rising very
slowly (Maul and Martin, 1993), although a persistent upturn in the rate of sea-level rise has begun in recent
decades. Geological studies show that in the more distant past, sea level around Florida and the world rose
or fell much more rapidly than in more recent times. The response of ice reservoirs to global warming is the
biggest unknown in the projections of sea level over the next century. The rate at which sea level rises is equally
as important to coastal resources as how much it rises.
WHAT WE KNOW:
Florida sea-level rise can, for most practical societal purposes, be considered to be essentially
similar to global sea-level rise throughout the
state’s coastal areas (Merrifield et al., 2009).
The rate of global sea-level rise increased from
the 19th century to the 20th (Kemp et al.,
2009) and is still doing so. This rate increase is
due to both ocean warming and the contributions from both land-based ice melt from
glaciers and the ice sheets of Greenland and
Antarctica.
The most recent satellite observations confirm
global average sea-level rise to be about 80%
faster than the best estimate of the IPCC Third
Assessment Report. See Figure 1, reproduced
from Richardson et al. (2009).
Figure 1: Change in sea level from 1970 to 2008, relative to
the sea level at 1990. The solid lines are based on observations
smoothed to remove the effects of interannual variability (light
lines connect data points). Data in most recent years are
obtained via satellite-based sensors. The envelope of IPCC
projections is shown for comparison; this includes the broken
lines as individual projections and the shading as the uncertainty
around the projections.
II

3

II. Sea-Level Rise and Its Effects
on Florida’s Ocean
and Coastal Resources
EFFECT : Changes in Barrier Islands, Beaches, and Inlets
Beaches and inlets are regional systems of sediment deposition, erosion, and transport. These processes are
profoundly affected by changes in sea level and rates of sea-level change as well as by storm events. Scientists and resource managers will be challenged to separate the effects of sea-level changes from the effects
of storms and the alterations resulting from beach and inlet management actions.
WHAT WE KNOW:
Florida’s shoreline is both advancing because of
sediment accumulation and retreating (Sallenger et
al., 2006). On Florida’s Atlantic coast over the
past 100 years, shoreline position has advanced
by about 20 centimeters (about 8 inches) per year.
This shoreline advance occurred along approximately 60% of the coastline. The remaining 40%
of the coast retreated. The increases in elevation of
mean water levels combined with major hurricane
landfalls have increased barrier island erosion and
overwash deposition, contributing to shoreline retreat. This is a natural process that allows barrier
islands to migrate onshore and, potentially, maintain their elevations above sea level.
However, Florida has been successful in stabilizing
some of its beaches through nourishment and an
effective Coastal Construction Control Line program that maintains good location and construction standards along its coastline. These steps help
to counteract the long-term impacts of coastal erosion (Dehring, 2006; Klein and Osleeb, 2010).
Example: The coastline at Cape Canaveral is experiencing
steady, long-term erosion that is due to dune overwash. The
blue profile shows LIDAR elevations sampled in November of
1999. The red profile shows the elevations in 2006. The
dune and beach have migrated approximately 12 meters
inland in this period. The slight increase in dune elevation is a
result of restoration efforts. (Photo and diagram: USGS)
II

4

II. Sea-Level Rise and Its Effects
on Florida’s Ocean
and Coastal Resources
New inlets can be cut through barrier islands by
waves superimposed on storm surges (Sallenger et
al., 2005, 2006). When barrier island dune elevations are reduced below a threshold that allows
complete inundation during storms, the overland
flow of water can cut a channel (breach) that connects ocean and estuary (Sallenger et al., 2005,
2006). The threshold may be reached by increasing the surge elevations (more powerful storms),
raising the sea level, or progressively eroding and
lowering the dune elevations—or all three at once.
Even with beach nourishment and other mitigation
efforts, there will be an increase in the impacts on
coastal infrastructure. This is an ongoing problem
associated with populations being located near
the shoreline and at low elevations.
Example: North Captiva Island, Florida, breaching as a
result of the landfall of Hurricane Charley in 2004. (Photo:
USGS)
Example: The top photograph in each pair was obtained prior to landfall of (left) Hurricane Frances and (right) Hurricane Ivan,

Global average sea level will rise by 0.5–1.0 meter

(about 20–40 inches) and possibly more by 2100

(National Research Council, 2010).

WHAT IS POSSIBLE:

Major inputs of water from the melting of high-latitude and high-altitude ice reservoirs could cause a

global average sea-level rise of up to two meters this

century and several more meters over the subsequent

centuries (Rahmstorf, 2010).

II. Sea-Level Rise and Its Effects

on Florida’s Ocean

and Coastal Resources

DRIVER: Sea-Level Rise

Florida’s geology, chemistry, biology, and human population have already been, and will continue to be, profoundly

affected by rising sea levels. For the past few thousand years, sea level around Florida has been rising very

slowly (Maul and Martin, 1993), although a persistent upturn in the rate of sea-level rise has begun in recent

decades. Geological studies show that in the more distant past, sea level around Florida and the world rose

or fell much more rapidly than in more recent times. The response of ice reservoirs to global warming is the

biggest unknown in the projections of sea level over the next century. The rate at which sea level rises is equally

as important to coastal resources as how much it rises.

WHAT WE KNOW:

Florida sea-level rise can, for most practical societal purposes, be considered to be essentially

similar to global sea-level rise throughout the

state’s coastal areas (Merrifield et al., 2009).

The rate of global sea-level rise increased from

the 19th century to the 20th (Kemp et al.,

2009) and is still doing so. This rate increase is

due to both ocean warming and the contributions from both land-based ice melt from

glaciers and the ice sheets of Greenland and

Antarctica.

The most recent satellite observations confirm

global average sea-level rise to be about 80%

faster than the best estimate of the IPCC Third

Assessment Report. See Figure 1, reproduced

from Richardson et al. (2009).

Figure 1: Change in sea level from 1970 to 2008, relative to

the sea level at 1990. The solid lines are based on observations

smoothed to remove the effects of interannual variability (light

lines connect data points). Data in most recent years are

obtained via satellite-based sensors. The envelope of IPCC

projections is shown for comparison; this includes the broken

lines as individual projections and the shading as the uncertainty

around the projections.

II

3

II. Sea-Level Rise and Its Effects

on Florida’s Ocean

and Coastal Resources

EFFECT : Changes in Barrier Islands, Beaches, and Inlets

Beaches and inlets are regional systems of sediment deposition, erosion, and transport. These processes are

profoundly affected by changes in sea level and rates of sea-level change as well as by storm events. Scientists and resource managers will be challenged to separate the effects of sea-level changes from the effects

of storms and the alterations resulting from beach and inlet management actions.

WHAT WE KNOW:

Florida’s shoreline is both advancing because of

sediment accumulation and retreating (Sallenger et

al., 2006). On Florida’s Atlantic coast over the

past 100 years, shoreline position has advanced

by about 20 centimeters (about 8 inches) per year.

This shoreline advance occurred along approximately 60% of the coastline. The remaining 40%

of the coast retreated. The increases in elevation of

mean water levels combined with major hurricane

landfalls have increased barrier island erosion and

overwash deposition, contributing to shoreline retreat. This is a natural process that allows barrier

islands to migrate onshore and, potentially, maintain their elevations above sea level.

However, Florida has been successful in stabilizing

some of its beaches through nourishment and an

effective Coastal Construction Control Line program that maintains good location and construction standards along its coastline. These steps help

to counteract the long-term impacts of coastal erosion (Dehring, 2006; Klein and Osleeb, 2010).

Example: The coastline at Cape Canaveral is experiencing

steady, long-term erosion that is due to dune overwash. The

blue profile shows LIDAR elevations sampled in November of

1999. The red profile shows the elevations in 2006. The

dune and beach have migrated approximately 12 meters

inland in this period. The slight increase in dune elevation is a

result of restoration efforts. (Photo and diagram: USGS)

II

4

II. Sea-Level Rise and Its Effects

on Florida’s Ocean

and Coastal Resources

New inlets can be cut through barrier islands by

waves superimposed on storm surges (Sallenger et

al., 2005, 2006). When barrier island dune elevations are reduced below a threshold that allows

complete inundation during storms, the overland

flow of water can cut a channel (breach) that connects ocean and estuary (Sallenger et al., 2005,

2006). The threshold may be reached by increasing the surge elevations (more powerful storms),

raising the sea level, or progressively eroding and

lowering the dune elevations—or all three at once.

Even with beach nourishment and other mitigation

efforts, there will be an increase in the impacts on

coastal infrastructure. This is an ongoing problem

associated with populations being located near

the shoreline and at low elevations.

Example: North Captiva Island, Florida, breaching as a

result of the landfall of Hurricane Charley in 2004. (Photo:

USGS)

Example: The top photograph in each pair was obtained prior to landfall of (left) Hurricane Frances and (right) Hurricane Ivan,