Climate change will cost U.S. coastal areas twice what analysts had predicted, according to a new study. Researchers had estimated that preparing coastal cities, repairing property damages, and relocating inhabitants for future sea level rise could have a roughly $500 billion price tag by 2100. But storm surge from tropical cyclones can cause additional local rises in sea level rise; that figure hits about $1 trillion, researchers report this month in Climatic Change. Researchers modeled the combined effects of sea level rise and U.S.-striking tropical cyclones on coastal property around the country. They chose 17 multicounty areas on the Gulf, East, and Pacific coasts and then estimated the impacts to the remaining, nonmodeled coastal areas based on how the modeled areas closest to them were impacted. The team also assumed that society would spend billions on adaptation measures, which studies suggest could be a cost-effective policy measure. Among these measures are abandoning properties in low-level areas, adding more sand to beaches, and building barriers to reduce beach erosion. The costs from sea level rise and storm surge together, including adaptation, total $930 billion to $1.1 trillion nationally by 2100, 84% to 110% higher than from sea level rise alone, the researchers found. The Gulf and East coasts would suffer nearly all the costs. Future costs would be $84 billion to $140 billion lower if emissions of the greenhouse gas carbon dioxide were to level off and gradually fall, but most impacts through midcentury are already locked in because emissions cuts take time to work, the researchers say. The study, they warn, doesn’t account for potential additional damages to business activity, infrastructure such as roads and power grids, and natural resources and wildlife.