Sea Level 101
What are the Impacts of Sea Level Rise?
Flooding during high tides and storms will worsen in many locations in the U.S. due to sea level rise.
Sea Level Rise Worsens FloodingSea Level Rise is Making Flooding Worse
Sea levels are rising due to human-caused climate change. However, this rise varies from place to place, and so does its impacts on the United States' diverse coastlines. As sea levels rise, many coastal places will experience more frequent and widespread flooding during high tides and storms over the next 30 years and beyond. This is because sea level rise adds height on top of already existing sea levels. For example with 4 inches of sea level rise, if a water level used to reach 12 inches high during high tide or a storm, that same event would now reach 16 inches or more. And that extra height can push a flooding event further inland, causing greater damage.
This will only get worse as sea levels rise further in the coming decades and longer. For example, moderate high tide flooding which causes damage to buildings and infrastructure currently happens less than once per year on average in East and Gulf coasts communities. However, by 2050 these same flooding events are projected to occur 3-10 times per year.
The impact of sea level rise has already been felt by many coastal communities in the U.S. Due to sea level rise, in 2024 the U.S. now experiences five more days where flooding occurs compared to what happened in 2000. These impacts are being experienced most prominently along the East and Gulf coasts of the U.S. where sea levels are rising the fastest.
To find out more about changes in flooding related to sea level rise in your area, go to the National Sea Level Explorer.
Impacts to Coastal CommunitiesSea Level Rise Also Impacts Coastal Communities’ Land, Infrastructure, Economies, and People
In addition to flooding, there are a variety of other impacts from sea level rise coastal communities are already starting to experience. Many of these impacts are happening at the same time, leading to extra stress on communities. Communities that lack resources to protect them or to adapt are at even higher risk of harm.
At the shoreline, the added height from sea level rise can speed up erosion. Erosion can impact natural habitats and lead to the loss of land and property. When combined with flooding, erosion can damage roads, bridges, sewage systems, power plants, and other key infrastructure for the community. This can lead to health risks through the spread of waterborne diseases.
Below ground, saltwater can seep into freshwater aquifers as sea levels rise, known as saltwater intrusion. When saltwater mixes with the fresh groundwater, the water becomes unusable for drinking and agriculture. Furthermore, coastal and marine ecosystems that support industries and provide natural storm protection, resources and ways of life are all at risk of changing or degrading due to sea level rise.
Sea level rise impacts can lead to economic hardships for a community. In particular, communities that rely on coastal tourism, fisheries, and shipping may feel the impacts most deeply. Plus, many coastal communities also have a rich history that ties their culture to the water. These changes could lead to a loss of heritage sites or cultural practices.
However, actions are being taken in many coastal communities to help plan for and address these impacts.
Dive Deeper: The many factors that influence the impacts of sea level rise on coastal communities.