U.S. Coastal Sea Level Rise Rate Doubled in Past Century, New Study Finds

By Woods Hole Oceanographic Institution, whoi.edu.

For harbor operators and coastal infrastructure planners, accurate sea level data is essential for making critical decisions about dock elevations, bulkhead construction, and long-term facility planning. A new scientific study highlighting significant acceleration in U.S. coastal sea level rise has important implications for harbors nationwide, particularly as communities assess the adequacy of current flood protection measures and plan for future waterfront development.

According to a Woods Hole Oceanographic Institution press release:

A new study by Chris Piecuch, a physical oceanographer with the Woods Hole Oceanographic Institution (WHOI), finds that the rate of U.S. coastal sea-level rise has more than doubled in the past 125 years, from a rate of less than 2 millimeters per year in 1900 to more than 4 millimeters per year in 2024, and that present rates are well above the historical average. This translates to a rise in U.S. coastal sea level of about 40 centimeters, or nearly 16 inches, over that time.

In contrast to a DOE report that analyzed data from just five tide gauge locations, the Piecuch study uses data from 70 tide gauges distributed along the contiguous U.S. coast. The data set comprises all active U.S. tide-gauge stations with more than 30 years of data.

“The DOE report paints an incomplete picture of the rates of sea level change by picking just a handful of locations that are subject to local effects and that are not representative of the large-scale aggregate relative sea level behavior,” said Piecuch.

The study, published in the journal AGU Advances, concludes that the acceleration represents “conclusive evidence that coastal sea level in the U.S. is accelerating, likely due to climate change.” The findings are consistent with global patterns related to ocean warming, thermal expansion, and ice loss from glaciers and ice sheets.

Originally published December 17, 2025, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts.

High tide flooding in Boston Harbor. Photo Shutterstock, Keith J Finks