Sea Level Rise and Coastlines
Rising and falling sea levels can change the coastlines. Sea levels fall during the ice ages (glaciation) because glaciers and ice sheets trap and hold enormous amounts of water from the world’s oceans causing the coastlines to expand into the sea. Such a scenario is called an emergent coastline. In the opposite event where the ice sheets and glaciers melt (interglacial periods), sea levels rise causing the formation of a submergent coastline. Currently, the sea levels are rising at a rapid rate, and cities around the world are preparing for the retreating coastlines. Watch the following video on how two cities in the US are responding to the rapidly rising sea levels.
Exercise 8 – Sea Level Rise
Answer the following questions:
- New York City and Charleston, SC are examples of:
- Submergent coastlines are a normal coastal process that is a result of glacial and interglacial periods on Earth. T/F
- What evidence of rising sea levels is observed in the Charleston area?
- What are the predictions for the rise in sea levels in the Charleston area over the next 100 years?
Climate Central is a research nonprofit that studies coastal hazards including sea-level rise. It is expected that the sea levels will rise depending on the measures taken by the global community to curb CO2 emissions and curb climate change and its impacts. Click on Climate Central | Land below water link and let’s focus on Folly Beach County Park at the Southwestern end of Folly Beach and the College of Charleston campus SSM building on 202 Calhoun St.
First, click on “Choose Map” on top and select “Year“.
- In the year 2030, is SSM Building accessible by road?
- By which year is the sea level expected to be next to the building?
- In the year 2030, is Folly Beach County Park accessible by road?
- In the year 2030, is the Town of Folly Beach accessible by road (Hwy 171, Folly Beach Rd)?
Now, click on “Choose Map” on top and select “Water Level“.
- At 3 ft above current sea level, is SSM Building accessible by road?
- At which water level above the current sea level makes the sea arrive next to the SSM building?
- At which water level above the current sea level does the Folly Beach County Park become inaccessible?
- At which water level above current sea level does the is the Town of Folly Beach become inaccessible by road (Hwy 171, Folly Beach Rd)?
Topography of Coastlines
The topography of the coastlines can also impact how quickly a coastline can submerge or become susceptible to coastal storms and erosion. Some coastal features are more likely to be found on different coastlines.
Exercise 9 – Coastal Topography
The USGS National Map is an excellent resource to study different geological and geographical features within the US. Let’s use this map to study two coastal regions – one near San Francisco, CA, and one near Folly Beach, SC.
First, click the link to explore the Point Reyes National Seashore to explore the topography of this area.
- What is the approximate elevation at the southern edge of Point Reyes Headland? (Click on “XY” tool at the top right of the map, then click “Activate” and then click on the point of interest.)
- Looking at the scale of the map at the bottom left of the screen, what is the approximate relief at the edge of this coastline? (Divide elevation of the edge above sea level by the distance to the water in feet.)
- Based on this topographical information, do you expect this headland to experience erosion?
- Explain your previous answer.
Now let’s return to Folly Beach at this link to explore the topography here.
- What is the approximate elevation at the Folly Beach County Park? (Click on “XY” tool at the top right of the map, then click “Activate” and then click on the point of interest.)
- Looking at the scale of the map at the bottom left of the screen, what is the approximate relief at the edge of this coastline? (Divide elevation of the edge above sea level by the distance to the water in feet.)
- Based on this topographical information, do you expect this park to experience erosion?
- Explain your previous answer.
