Higher Tides, Shorter Timelines

The rate of sea-level rise along U.S. coastlines has more than doubled over the past 125 years, according to a new analysis that examined data from scores of tide gauges from around the country.

The findings stand in contrast to a wide-ranging, widely criticized assessment of climate science that the Trump administration released this summer.

Chris Piecuch, a sea-level scientist at Woods Hole Oceanographic Institution, said he undertook his analysis in response to that Energy Department report, which he and others argue uses cherry-picked data to conclude that “U.S. tide gauge measurements reveal no obvious acceleration beyond the historical average rate of sea-level rise.”

Piecuch said that while the rate of rising seas varies from place to place, the full range of available data leads to “a dramatically different conclusion” about what is actually unfolding along the nation’s coastlines.

“If you want to be thorough, you take all the data we have. When you do that, you find pretty unambiguous evidence of sea-level rise over the past century” in much of the country, said Piecuch, the author of the study published Wednesday in the journal AGU Advances.

“It’s not politics. That’s what the data say.”

Over the past century, as the Earth’s atmosphere has continued to heat up, scientists have documented roughly eight inches of global sea-level rise as oceans expand and land-based ice sheets melt. In addition, researchers have detailed how the rate of global sea-level rise has doubled over the past three decades due largely to changes in the climate — an acceleration that NASA highlighted earlier this year.

But less research has focused on more local and regional changes in sea levels, which can be influenced by a variety of forces.

In the handful of tide gauges highlighted in the Trump administration report, including places such as Galveston, Texas, and Grand Isle, Louisiana, the authors argue that natural factors such as sinking land, and human-caused factors such as oil and gas extraction play a more prominent role than global warming in accounting for relative changes in sea levels.

That assessment also underscores that some places, such as the Pacific Coast, have experienced little sea-level rise compared with places such as the gulf coast. Some spots in Alaska have even seen an overall decrease as sea-level rise is outpaced by a phenomenon known as “glacial rebound,” where the land lifts as glaciers recede.

Piecuch is quick to acknowledge that there are indeed many such local forces at work, leading different areas of the country to record higher or lower rates of “relative” sea-level rise. But the overall trajectory, he said, is anything but murky.

“None of those factors would cause the large-scale, nationwide sea-level acceleration that’s clearly seen when you look at U.S. tide gauges in aggregate,” he said.

A group of 85 scientists who issued a joint rebuttal to the administration’s climate science report this summer agreed. They cited what they called a series of errors and misrepresentations, labeling its conclusions “a vibes-based assessment of sea-level acceleration” that “performs no statistical analysis” and fails to consider the economic impacts already occurring.

For his study, Piecuch used data from 70 tide gauges distributed along the continental United States. While only about a dozen active U.S. tide gauges have records that date to the turn of the 20th century, the study says, scientists and statisticians have developed and published methods to account for “gappy, noisy, heterogeneously distributed datasets.”

The result, Piecuch found, was that the average rate of sea-level rise along American coastlines went from about slightly less than 2 millimeters per year in 1900 to more than 4 millimeters per year in 2024. In addition, he writes, gauges show “obvious evidence” of a more recent acceleration in sea-level rise.

“What surprised me is just how rapid the change is,” Piecuch said.

Coastal engineer Sönke Dangendorf, who was not a co-author on Wednesday’s study but has worked on sea-level research with Piecuch in the past, said the analysis is meticulous and important.

“This is indeed a novel thing. Nobody else has really done that before,” Dangendorf said. “Chris did this with a lot of statistical rigor.”

Documenting what is happening — and likely to happen — around the United States is critical in being able to help communities adapt and prepare for rising seas. “It’s already reshaping our coastlines,” he said.

In an in-depth series of stories last year, The Washington Post documented how the American South has experienced one of the most rapid surges of sea levels anywhere on the planet — even when accounting for sinking land, known as subsidence.

At more than a dozen tide gauges spanning from Texas to North Carolina, sea levels had risen at least six inches higher than they were in 2010 — a change similar to what occurred over the previous five decades. A Post analysis of satellite data showed that the Gulf of Mexico has experienced twice the global average rate of sea-level rise since 2010.

The real-world consequences of such change are growing, The Post found. In Louisiana, some wetlands are in a state of “drowning.” Choked septic systems are failing and threatening to contaminate waterways in South Florida and elsewhere. Insurance companies are raising rates, limiting policies or even pulling coverage in vulnerable places. Some roads are increasingly falling below the highest tides, leaving residents delayed or stranded until waters recede.

A growing body of research also has documented how fast-rising seas are forcing coastal communities to endure flooding more frequently than previously thought — and more often than federal tide gauges would suggest.

In one study published in June, two North Carolina researchers installed sensors inside stormwater drains and cameras above each to document the true prevalence and duration of flooding in several communities. They found that instances of “sunny day flooding” were far more prevalent than official predictions.

“I view it as a harbinger of what’s to come,” Katherine Anarde, a coastal engineering professor at North Carolina State University, told The Post at the time.

The National Oceanic and Atmospheric Administration has said that on average, the United States will experience as much sea-level rise by 2050 as it did over the preceding century. And while a certain amount of rising seas are baked in over the coming decades, scientists say, how much depends largely on whether humans significantly cut greenhouse gas emissions caused by burning fossil fuels.

The Energy Department climate report this year, which also cast doubt on long-term forecasts of the continued acceleration in sea-level rise, generally concluded that human-caused global warming is less economically disastrous that commonly believed and that the aggressive mitigation strategies most of the world’s nations have agreed to pursue might be misguided.

“Climate change is real, and it deserves attention,” Energy Secretary Chris Wright said upon its release. “But it is not the greatest threat facing humanity.”

The Energy Department did not respond to a request for comment on Wednesday’s study.

In August, the advocacy groups Environmental Defense Fund and the Union of Concerned Scientists, filed a federal lawsuit claiming the Trump administration illegally sought out a secret group of “five handpicked skeptics” to produce a report casting doubt on mainstream climate science. The goal, the lawsuit asserts, was to “manufacture a basis to reject this overwhelming scientific consensus” and to use the report as a basis for undermining key federal climate regulations.

That litigation is ongoing.

Also ongoing, Piecuch said, is the steady uptick in sea levels. Climate models and real-world observations “tell a pretty darn similar story” over the coming years.

“All the scientific evidence,” he said, “points to the fact we’re going to continue to see an acceleration into the future.”

https://www.washingtonpost.com/climate-environment/2025/12/17/sea-level-rise-doubling-trump-report/