Investigating Sea Level Trends in the United States
How it works
The problem of the rise of sea levels isn’t a singular country’s issue, or a west or east coast issue, it is a world issue. The global sea rise has created monumental issues, such as storm surges becoming deadly and excessive flooding further inland. These may seem like issues that already occur, but the rising water levels make them all the more serious. The biggest factors in the sea levels increasing is thermal expansion caused by the warming of our oceans and a large amount of ice melting off of glaciers and ice sheets such as Greenland. All of that runoff must go somewhere, and when it enters the ocean, levels rise. When the heat from our emissions enters the ocean, the water absorbs the majority of the emissions, which warms the water. Economically, the coasts hold massive amounts of populations that are affected by tropical storms, hurricanes, and rising sea levels. All of this is connected, and rebuilding what was destroyed by these surges is very costly.
Investigating the problem: Sea level trends for the East, West, and Gulf coast
The following table presents a visual representation of the trend in sea level rising in the past 100 years with fifteen different locations from the East coast, West coast, and Gulf Coast of the United States.
How it works
In summary, this table shows the relative trend, the time frame of data, and the change in 100 years. For the East coast, we see an average of 3.56 mm per year relative trend with an average increase of 1.17 feet over 100 years. The West coast varied from north to south, with some, such as Crescent City, CA, actually decreasing, but North Spit had a 4.81 mm relative trend. The Gulf coast was what shocked me the most, especially with the 9.08 mm relative trend for Grand Isle, LA. The average relative trend for the Gulf coast was a total of 4.608mm per year. As we can see from these numbers, rising sea levels are an issue, and it is a reality. The data doesn’t lie, and for places such as Grand Isle, LA, and our own area of Sewell’s Point, VA, it is something we must try to change.
Why are there differences in sea levels from coast to coast? On the East coast, there are three major factors in the rise of sea levels. The slowing of the Gulf Stream, the EL Nino cycle, and changes in North Atlantic weather patterns. Scientists are referring to some flooding as “sunny day” flooding, and one scientist in particular name William Sweet, who is an NOAA oceanographer, investigated what is causing this issue. He used data from buoys to track the speed of the Gulf Stream and found that a northeasterly wind and the slowing of the stream are actually causing these sunny day floods. Another researcher named Tal Ezer, who is an oceanographer at ODU, also looked at the currents and weather patterns to explain this rise in sea level on the east coast. What he found by using satellites was that the sea surface elevation across the Gulf Stream has a slope. This slope on the coastal side can be a few feet lower than on the east side. When the Gulf Stream’s current is flowing stronger, this causes the slope to be steeper, which is caused by the Earth’s rotation. When the stream slows, that slope will decrease, which pushes more water up against the land, ultimately causing flooding during the high tides.
The second and third factor was the El Nino years which we learned about in class as well. We know that El Nino happens in the Pacific Ocean, but its effects go across our continent, which affects a change in wind patterns and water levels rising along the East coast. The change in weather affects the jet stream, and more wind comes with storms, and this changes the distribution of water in the North Atlantic Ocean, which increases sea levels along the East Coast. What scientists found was that El Nino actually controls the increases and decreases of water on the coast.
The sea level trends in the Gulf Coast are some of the highest and worst in the United States. With the warm waters of the Gulf Coast, if a hurricane makes its way into them, it will intensify and be even more dangerous and deadly, as we saw with Hurricane Katrina and Hurricane Harvey. As I’ve stated previously, the factors that affect the East coast also affect the Gulf Coast, but on top of that, summer tides are getting higher, and winter tides are getting lower because the summers and winters are becoming hotter and colder. This cycle, along with air temperature and air pressure, plays massive roles in the rising of sea levels. Even if the changes in tide are small, this still leads to more storm surges and flooding, which we have witnessed in our own communities of Norfolk and Virginia Beach.
The East coast is affected by the melting ice sheets of Greenland, but the West Coast suffers from the same, just from Antarctica. Both continents are melting, and the rates are increasing, which isn’t just a United States issue but a global issue. Warming waters and melting glaciers are the biggest factors in the global sea level rise. The El Nino years affect the West coast even more than the East and Gulf because they occur right in the Pacific Ocean. This can set off even stronger storms and, due to the sea level rise, leads to more landslides and floods. Plate tectonics plays a role due to the lifting of land along the west coast. Where the Pacific and North American plates slide past each other on the San Andres fault line, there is a change in sediment and water. This causes areas to shift lower and lower every year while the sea levels increase. Over time eventually, these will catch up to each other, with parts of California left underwater.
Implications of Changing Sea Levels on the Local Level
I personally live in the area code 23507, which is very close to the Chelsea district of Ghent. I know we are in zone A which speaks for itself, considering we would be the first to be told to evacuate. If we are the first to evacuate, then it doesn’t take much research to know we are the most at risk for flooding issues. According to the risk finder website, there are 2.900 people in this area code that lives on exposed land below 6 ft. 2.900 people live here in this part of zone A. 1869 of them are in the low social vulnerability population. Older residents and residents with mental disabilities are common in my area. Not only that, but we also live right near the tunnel and the shipyard. That’s tons of transportation and movement, which put a lot of people at risk in the case of a deadly flood, not to mention the destruction of homes which, according to the website, was an average of $367 million! I feel like there doesn’t need to be that much argument for the mitigation of this issue in this area. It seems like a no-brainer to me that if any number of people live somewhere, especially in a high-risk zone, then something should be done to protect them and the city’s land. Not only would there be large impacts on personal property, but economically, there’s a chance of loss of jobs in trade due to the shipyard and rail system close to my house and the tunnel tolls.
Adapting and Mitigating to Sea Level Changes
In the area where I live, every single time it rains hard, the streets flood. During a single rain storm, not even a hurricane, just a storm, the street next to us actually flooded enough to go over the hood of cars parked there. In that historic district, there are a few streets with brick that do not have drainage on them. If a street is going to flood in a storm, imagine what would happen to the entire area during a hurricane! One of the strategies I think would help to mitigate flooding issues would be more federal grants to assist people in the lifting of their homes. On Hampton Blvd in Norfolk, there are a few who have actually done so, but I don’t think as many people know about this possibility as much as they should. Perhaps hold meetings in the city to put out more information, maybe send out pamphlets in the mail from the city, but information needs to be provided in order to take advantage of this opportunity and potentially save your home from flood damage. Another strategy for this area would be to not build in areas that are prone to this. Build higher and in smarter locations where you can control rain runoff. This goes along with maybe having a rule or law passed making it mandatory for new builders of any kind to lift their buildings a certain amount of feet. This prevents them from building low and potentially claiming large numbers on their insurance and/or losing their property to flood and damages. Lastly, the mitigation strategies we could benefit from is maybe a sea wall like Galveston, Tx, implemented on their coast. This would not only cost a lot of money to make, but it would provide a lot of jobs in the time it took to create. This would be a long-term solution but at a high cost.