Understanding Rising Sea Levels

Rising sea levels are a significant concern for coastal communities worldwide. As global temperatures increase, polar ice caps and glaciers are melting, ocean waters are heating and expanding, all contributing to higher ocean levels. Locally, sea levels rise or fall relative the motion of the land at any location. Relative sea-level rise rates in the Chesapeake Bay are some of the highest along the U.S. east coast because the land is subsiding in and around the Chesapeake Bay from natural and human-induced causes. This phenomenon poses risks such as flooding, erosion, and habitat loss.

Causes of Rising Sea Levels

There are several digital tools available to help the public visualize the impact of rising sea levels on the landscape. The National Oceanographic and Atmospheric Administration (NOAA) has created a “Sea Level Rise Viewer "that allows the user to simulate water level rise in map view and on photos at local places. As you increase the water level on the slider, the water levels rise over the land’s topography (the land’s elevations) much like the water levels in a bathtub rise to fill the contour of the tub. Although useful for illustrating the scale of potential flooding, the “bathtub” model does not account for erosion, land subsidence, or future shore construction.

Explore sea-level rise impacts, high tide flooding, marsh migration, vulnerability, and local scenarios through NOAA's Sea Level Rise Viewer: Sea Level Rise and Coastal Flooding Impacts. Tutorials are available.

“The first few feet of sea-level rise alone will displace more than 100 million people worldwide and turn all our major Gulf and Atlantic coast cities into pre- Katrina New Orleans - below sea level and facing super-hurricanes.”

- Joseph J. Romm