The sea is higher than we thought and millions more are at risk, study finds

The sea is higher than we thought and millions more are at risk, study finds A new study in the journal Nature says most sea level rise research may have underestimated coastal water heights by an average of 1 foot or about 30 centimeters By SETH BORENSTEIN Associated Press and ANNIKA HAMMERSCHLAG Associated Press March 4, 2026, 11:01 AM Climate change's rising seas may threaten tens of millions more people than scientists and government planners originally thought because of mistaken research assumptions on how high coastal waters already are, a new study said. Researchers studied hundreds of scientific studies and hazard assessments, calculating that about 90% of them underestimated baseline coastal water heights by an average of 1 foot (30 centimeters), according to Wednesday's study in the journal Nature . It's a far more frequent problem in the Global South, the Pacific and Southeast Asia, and less so in Europe and along Atlantic coasts. The cause is a mismatch between the way sea and land altitudes are measured, said study co-author Philip Minderhoud, a hydrogeology professor at Wageningen University & Research in the Netherlands. And he attributed that to a “methodological blind spot” between the different ways those two things are measured. Each way measures their own areas properly, he said. But where sea meets land, there's a lot of factors that often don't get accounted for when satellites and land-based models are used. Studies that calculate sea level rise impact usually “do not look at the actual measured sea level so they used this zero-meter” figure as a starting point, said lead author Katharina Seeger of the University of Padua in Italy. In some places in the Indo-Pacific, it's close to 3 feet (1 meter), Minderhoud said. One simple way to understand that is that many studies assume sea levels without waves or currents, when the reality at the water's edge is of oceans constantly roiled by wind, tides, currents, changing temperatures and things like...