No Evidence Climate Change Has Accelerated Sea Level Rise, Finds First Global Study Of Real World Data
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{Michael Shellenberger
@shellenberger | 02 September 2025}
Climate change will make oceans rise 3 - 10 feet by the end of this century, said scientists and the media. Nonsense. A new, first-ever global study of real world data, not models, finds no evidence climate change accelerated sea level rise. This is a massive scientific scandal.
For over a quarter-century the world’s leading climate scientists and news media have warned that human-caused climate change has doubled the rate of sea level rise and is thus putting civilization in grave danger. “We will see at least four feet of sea level rise and possibly ten by the end of the century,” wrote The New York Times’ David Wallace-Wells in 2019. “The oceans we know won’t survive climate change,” claimed The Atlantic that same year. The author, Robinson Meyer, quoted estimates by Princeton University’s Michael Oppenheimer that sea levels would rise by more than 34 inches by 2100.
When I asked Oppenheimer about those numbers at the time, he told me, “The actual number, which is based on the sea level rise amount in [IPCC Representative Concentration Pathway] 8.5 for its [Special Report on the Ocean and Cryosphere in a Changing Climate] report, is 1.1 meters, which is 3 feet, 7 inches,” or 43 inches.
All of those claims have been proven false by the first-ever global study of sea level rise based on data gathered locally rather than on models extrapolating from assumptions. The Journal of Marine Science and Engineering published the peer-reviewed article, “A Global Perspective on Local Sea Level Changes,” by Hessel Voortman, a Dutch engineer, and Rob de Vos, a researcher, last week.
“The average rate of sea level rise in 2020 is (only) around 1.5 mm/year (15 cm per century),” said Voortman. “This is significantly lower than the 3 to 4 mm/year often reported by climate scientists in scientific literature and the media.”
Indeed, the significance of the study lies in the fact that most of what the media and climate scientists claimed about climate change and sea level rise was false. Scientists and the media tend to focus on the IPCC projections of the extreme uppper end of sea level rise despite reality tracking at the very low end.
Voortman conducted the research without financial support and does not deny the reality of climate change, sea level rise, or the need for models. “It is important to stress that there are good reasons to have models. If we as engineers design something in the coastal zone, then we try to achieve a technical lifetime of 50 to 100 years, and that means we need to try to look into the future.”
An expert on the impacts of climate change, Roger Pielke, Jr., said, “Most people are not aware that the scientific community uses different concepts to discuss sea level rise. What matters for communities is what happens where they are located, not an abstract global average.”
Headlines about sea level rise have been catastrophic for decades. Because of sea level rise, the earth would become “uninhabitable,” said The Times’ Wallace-Wells in 2019. “As oceans rise,” wrote Brad Plumer in The New York Times in 2020, “crashing waves and extreme high tides will be able to reach farther inland, putting tens of millions more people and trillions of dollars in assets worldwide at periodic risk of flooding.”
Plumer’s article assumed sea levels would rise 12-36 inches. Instead, it appears they could increase just six inches, the same as during the 20th Century.
Strikingly, nobody in over 25 years of research had done what Voortman and De Vos did. “It is crazy that it had not been done,” said Voortman. “I started doing this research in 2021 by doing the literature review. ‘Who has done the comparison of the projections with the observations?’ And there were none.”
Nobody paid Voortman to do his study, nor does he belong to a university. “I'm a hydraulic engineer by profession, almost 30 years now, and involved in flood protection, coastal infrastructure adaptation projects all over the world,” he explained. “From practice, I had already encountered the situation that sea level projections were exceeding sea level observations.” First he published a paper in 2023 on the discrepancy between projections and what was happening in the Netherlands. “Then, I decided to try to analyze as many locations over the world as possible.”
In other words, despite billions of dollars poured into climate science over the last 25 years from governmental and philanthropic sources, with major climate centers in universities around the world, no scientist had done what Voortman did, without money, off the side of his desk.
Why did the media and scientists get sea level rise so terribly wrong? And why didn’t anyone bother comparing real world data to the predictions of the models? Graduate students sometimes struggle to find gaps in the scientific literature to fill. Why didn’t any of them notice this one? Why did it take an engineer volunteering his time to determine whether sea level rise was accelerating?
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