Sea levels along the United States coast are rising faster than they did in the past, and new research shows that the change is not subtle.
A study published in AGU Advances reveals that the pace of coastal sea level rise has more than doubled over the last century, directly challenging recent claims that U.S. sea levels are not accelerating
In July 2025, a report from the U.S. Department of Energy argued that tide gauge data across the country show no clear increase beyond a long term average rate.
That conclusion, however, does not hold up when the full body of available data is examined.
Physical oceanographer Chris Piecuch from the Woods Hole Oceanographic Institution (WHOI) took a broader approach and reached a very different result.
How sea level rise is measured
Scientists use tide gauges to measure sea level along the coast. These tools track how high the ocean rises compared to the land and, in some places, have been doing so for more than a hundred years.
Tide gauges are important because they show the sea level changes that coastal communities actually deal with.
At the same time, individual locations can tell an incomplete story. Local land can sink or rise over time due to geology or human activity.
Ocean currents, storms, and atmospheric pressure also affect short term readings. Looking at just a few tide gauges can exaggerate local effects and hide larger trends.
To avoid this problem, Piecuch analyzed data from 70 tide gauges spread along the contiguous U.S. coastline. Each site included more than 30 years of data.
By combining all of these records, the analysis reduced local distortions and revealed how sea level has changed at a national scale.
Data on sea level rise
The results point clearly in one direction. Around 1900, the U.S. coastal sea level was rising at less than 2 millimeters per year. By 2024, that rate had climbed to more than 4 millimeters per year.
Over 125 years, this added up to about 40 centimeters, or nearly 16 inches, of sea level rise along the U.S. coast.
“This represents conclusive evidence that coastal sea level in the U.S. is accelerating, likely due to climate change,” noted the study authors.
The analysis also shows that today’s rate of sea level rise sits well above the historical average calculated since 1900. Sea level rise has not stayed constant. It has picked up speed.
Why earlier conclusions fall short
The Department of Energy report based its conclusion on data from only five tide gauge locations.
According to Piecuch’s study, those sites are strongly influenced by local land changes and do not reflect large scale coastal behavior.
“U.S. tide-gauge records taken collectively do show an obvious RSL acceleration above the long-term historical average trend,” said Piecuch.
In contrast, the new study includes every active U.S. tide gauge with a long enough record to support meaningful analysis. This wider view changes the outcome entirely.
Local land motion and why it matters
Some coastal regions experience land subsidence, where the ground sinks over time. This can make sea level rise appear faster in certain places.
The DOE report focused on locations such as Grand Isle in Louisiana and Galveston in Texas, areas known for strong local land effects.
“These local and regional processes are thought to have caused significant land loss and subsidence, or sinking of coastal land, particularly during the 1960s and 1970s,” said Piecuch.
Processes like sediment movement linked to the Mississippi River and land compaction from oil and gas extraction play an important role locally.
However, these effects vary from place to place and do not explain why sea level rise is accelerating across the entire U.S. coastline.
Climate change drives sea level rise
The study acknowledges that vertical land motion influences relative sea level measurements.
However, land motion usually changes slowly and steadily over long periods. It does not create the kind of widespread acceleration seen in the data.
Piecuch points out that the U.S. coastal trend matches global patterns driven by ocean warming and the ongoing loss of ice from glaciers and ice sheets.
“You can’t argue that U.S. sea level rates are not increasing by looking at just five cherry-picked sites,” Piecuch said.
“When you consider all the available observations, the data point in the opposite direction – that U.S. coastal sea level is clearly on an accelerating course.”
Sea levels along the U.S. coastline
As sea level rise speeds up, coastal flooding begins from a higher baseline than before. High tides now reach farther inland, while storms cause more damage and place increasing strain on everyday infrastructure.
Roads flood more often, homes face repeated water damage, wetlands struggle to survive, and freshwater supplies come under pressure as saltwater slowly pushes its way in.
The study makes one thing clear. Old averages no longer match what is happening along U.S. coastlines today.
Sea level rise has not slowed down or stopped. It is happening faster, and future coastal planning will need to take that into account.
The study is published in the journal AGU Advances.
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