Scientists have found that sea levels along the world's coastlines are higher than previously assumed, with some places reaching up to 3 feet higher. The research suggests that the world is underestimating the threat and how quickly coastlines could disappear. The study, published in Nature, found that 90% of peer-reviewed studies on sea level rise only relied on assumptions from models rather than real, measured observations. 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. The researchers suggest that more work is needed to reevaluate global sea levels and the full implications of the risks posed to coastal communities.