A recent study published in *Nature* points out that the threat from sea-level rise caused by climate change is potentially greater than previously believed. The study, spearheaded by Katharina Seeger from the University of Padua, reveals that over 90% of existing studies on sea levels have been using a reference sea level that's lower than what's actually been measured along coastlines. This difference means that the risk of coastal flooding might be more serious, affecting tens of millions more people across the globe.