Sea levels along the world’s coastlines are much higher than previously assumed, more than 3 feet in some regions, according to new research, raising alarms that the world is underestimating the extent of the threat and how quickly coastlines could disappear.Sea level rise is one of the most visible and alarming impacts of the human-driven climate crisis, threatening hundreds of millions of people who live along global coastlines. Scientists estimate we’re already locked into around 6 inches of global sea level rise by 2050.But their calculations may not be starting from an accurate place, according to the study, published Wednesday in Nature.AdvertisementAdvertisementTo predict how sea level rise will affect coastal communities, scientists often use a model which estimates sea level by looking at the Earth’s gravitational field and rotation. But this doesn’t account for other influencing factors, such as tides, winds, ocean currents, temperature and saltiness.For reliable sea level information, the model should be combined with real-world satellite data that can accurately measure sea height, said Philip Minderhoud, a study author and an associate professor at Wageningen University and Research in the Netherlands.The report authors analyzed 385 peer-reviewed studies published over the past 15 years on sea level rise and the hazards it poses to coastlines. They found 90% relied only on assumptions from models rather than real, measured observations.It’s a “methodological blind spot” that has resulted in widespread underestimations of coastal sea levels and people’s exposure to their related hazards, Minderhoud said.AdvertisementAdvertisementGlobal coastal sea level is on average around 1 foot higher than currently assumed, the report found, with some places — such as Southeast Asia and parts of the Pacific — reaching up to 3 feet higher.The findings suggest that if sea level rises by around 3 feet, it would put 37% more land under water than currently assumed, affecting up to 132 million people across the world.“Simply put, if sea level in reality is higher for your particular island or coastal city than was previously assumed, the impacts from sea-level rise will happen sooner than projected,” Minderhoud said.The findi …