The Impact of Projected Sea Level Rise
Jordan King
John Kirk
Allison Perdue
Yanni Thomas
The Impact of Projected Sea Level Rise
Since time began, Earth has constantly been going through cycles
in several different aspects. One important cycle that affects
every other aspect of Earth is the sea level. Over millions of
years the earth flows back and forth between ice age and heightened
temperature, drastically changing the sea level. During these
times, the entire face of our planet changes, from the local
temperature all the way to the individual species that thrive in
certain areas. As a species, our main concerns with sea level
change are the CO2 emissions, impact on the coast and global
impact.
Sea level, since time began, has fluctuated greatly, primarily
due to the rotation and tilt of the earth. For thousands to
millions of years at a time the earth cycles between ice ages and
the sea level rising, the earths global temperature will increase
followed by a slow but steady drop. In times when the temperature
is increasing, the sea level increases with it. There are several
factors behind this, the three main reasons being thermal
expansion, melting of the ice caps and glaciers as well as ice loss
from Greenland and Antarctica. As the temperature increases, the
water gets warmer and expands raising the sea level, also the
rising temperature is not suitable for ice, causing a great deal of
it to melt.
The reason why sea level rise has become the issue it is today
is because humans have done a great deal of damage to earths
atmosphere, quickening the pace of earths natural cycle. Records
show little change in sea level from 0-1900 AD. At this point the
Industrial Revolution started as well as sea level rise at about a
rate of 1-2.5 mm/year. In 1992, the estimate was about 3 mm/year
and has only increased since then.
The history of CO2 levels can also be compared to the past
average sea levels to find a significant relationship between the
two. When looking at graphs of CO2 concentration, global
temperature, and sea level over the past thousands of years (Figure
1) a clear relationship is seen as each line on the graph is almost
identical. Whenever there is an increase in one part of the graph
there is almost a similar increase in the same part of the other
two lines. Although, a relationship is obvious on this graph, it is
hard to determine exactly what that relationship is based solely on
this graph. However, the graph matches what one would expect if CO2
was acting as a heat-trapping greenhouse gas that was raising the
global temperature and sea levels. The most popular theory of why
CO2 concentrations are affecting the earth is seen with their large
absorption of infrared radiation. This radiation comes from when
visible light and ultraviolet radiation hits and warms the earth.
The warm earth then emits the energy back out as infrared
radiation, which usually passes through the atmosphere unhindered.
However, when large concentrations of CO2 are in the atmospheric
air this infrared radiation is absorbed by the CO2 molecules which
then emit the energy in every direction including back at the
earth. This extra energy warms the earth even more which causes a
global rise in average temperature. A hotter average temperature
melts more ice from large ice caps. Since ice caps float above the
surface of the water, when they melt completely sea level can rise
globally by a significant amount. With the recent large increase of
CO2 concentration in the past 200 years, this relationship causes
serious concern for global climate. If the data from the past is an
indicator of the long term relationship between the three
variables, then a future global scale climate change might be on
the way. The long term future could hold a significantly warmer
Earth and a significantly higher sea level. Predictions and models
have estimated that the average global temperature can increase
anywhere from 2oF to 11.5oF depending on various variables. Sea
level predictions for that time go as high as a 4.9 feet
increase.
Figure 1.
It is already known that sea level fluctuates depending on the
earths climate. In the past several thousand years, sea level has
been continuously increasing, since the time of the last ice age.
Currently, the sea level in the Gulf area is rising at an
approximate rate of 1/5-inch-per-year. As ice and glaciers continue
to melt, the volume of ocean water increases and expands and as it
warms, leading to an accelerated rate of melting. Furthermore, the
current rate of sea level rise in the Gulf Coast area is expected
to, at the very least, double by the end of this century as the
atmosphere continues to warm and larger masses of ice melt into the
oceans. In Texas, two issues are actually occurring: the Gulf
waters are rising, and the coastal land is becoming less stable.
This is due in part to recent reductions in sediment deposits along
the coast resulting in coastal erosion and retreating shorelines.
Given this knowledge, the projected sea level rise along the Texas
coast ranges from a hopeful 1-2 feet increase, to the worst- case
scenario of almost 6 feet.
In addition to the detrimental effect on the physical coastline,
rising sea levels would also prove injurious to the socioeconomic
culture of the coast. Texas, as with many of the other Gulf Coast
states, has a high population density in its coastal counties in
comparison to the overall state. In fact, almost 25% of the states
entire population resides in the 18 coastal counties. A rise in sea
level would mean the displacement of potentially millions of people
to counties further inland. Furthermore, 10 of the nations busiest
ports are located in Texas, leaving a sizeable portion of the
shipping economy at risk of the negative impacts of changing sea
level. Texas ports receive approximately half of all foreign crude
oil imports into the country, and generate over $50 billion in tax
revenues and income, as well as providing millions of jobs. An
increase in sea level resulting in an altered coastline location
would lead to incredibly adverse effects on not only the Texas
economy, but the national as well. Without proper facilities along
the coast, shipping traffic as well as refineries would cease to
function and cripple the entire economy. In addition to the
pressing matters of CO2 correlation and coastal impacts, there are
various other major global consequences that are sure to emerge
with the slightest sea level rise. As the earth is mainly covered
by water (70%) the availability of drinking water does not seem to
be an issue, until it is taken into consideration that 97% of the
water is salt water. With the rise of ocean levels the preexisting
fresh water shortage is worsened as the salt water contaminates
both the surface and underground fresh water supplies. As water is
a basic and essential need for the continuation of life, this issue
is serious and should be addressed. It is also important to realize
that not only drastic changes can have repercussions, With [just]
one meter sea level rise some island nations, such as the Maldives,
would be completelysubmerged, (Sea Level Rise). In addition to
breaking apart the lives of the inhabitants,this increase can wipe
away what was once fertile farmland as well as further augmenting
water contamination. According to Greenpeace International, small
islands are not the only ones who have to worry about ending up
below sea level; New York, London, Shanghai, and Bangkok are only a
few of the larger cities who, if submerged, will cause massive
population displacement and economic instability. Another
significant complication that arises is the question, Do we have
the billions of dollars necessary to adapt to the changes and
destruction? In 2012 it was averaged that the re-acclimation to a
one meter sea level rise would cost us $156 billion (3% of total
GNP) as well as an extensive portion of land that would have to be
abandoned. Even as one of the worlds superpowers this is a huge
setback, so imagine the toll it would take on smaller, poorer
countries that do not have anywhere near as many resources.
In conclusion, sea level rise is an important matter that needs
to be addressed and a solution should be found. Even though it is a
cycle that the earth naturally goes through, humans are doing a
great deal to speed it up. This, in turn, will be very detrimental
for the generations to come
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Nov. 2013.
Current Sea Level
Low-end range: +8-12 inches
High-end range: +48-78 inches
A family living next to the sea in the village of Betio, on the
South Pacific island of Kiribati, pull themselves from the high
waves of the 'king tide'
