Title: Sea Level Rise | Smithsonian Ocean
Headings: Smithsonian Ocean
Smithsonian Ocean
Sea Level Rise
History of Sea Level Rise
Last Glacial Period
Sea Level on the Rise
Why is it Rising?
Thermal Expansion
Melting Ice
Other Contributions
Modern Sea Level
Measuring Global Sea Level
Changing Regional and Local Sea Levels
Impacts
Storms and Flooding
Changing Coastlines
Saltwater Intrusion
There's No Place Like Home
Regional Case Studies
Florida and the U.S. Gulf Coast
Island Nations
Alaska
River Deltas
Future Sea Level & Adaptation
Reducing Emissions
Holding Back the Sea
Moving Inland
Additional Resources

Content: Sea Level Rise | Smithsonian Ocean
Smithsonian Ocean
Credit: James Balog/Extreme Ice Survey
Sea Level Rise
Sections
Introduction
History of Sea Level Rise
Why is it Rising? Modern Sea Level
Impacts
Regional Case Studies
Future Sea Level & Adaptation
Additional Resources
Breadcrumb
Home
Through Time
Ancient Seas
Sea Level Rise
The Ocean Portal Team
Reviewed by Dr. Joshua K. Willis
(link is external)
, NASA-JPL, Dr. Andrew Kemp
(link is external)
, Tufts University, and Dr. Benjamin H. Strauss
(link is external)
, Climate Central
The ocean never stops moving. When you visit the beach, waves roll in and recede and the tides rise and fall. These are small daily changes that balance out over time. But over the past century, the average height of the sea has risen more consistently—less than a centimeter every year, but those small additions add up. Today, sea level is 5 to 8 inches (13-20 centimeters) higher on average than it was in 1900. That's a pretty big change: for the previous 2,000 years, sea level hadn't changed much at all. The rate of sea level rise has also increased over time.