“Coastal communities that are adapting to and preparing for future sea-level rise are largely adapting to the amount of sea-level rise that has already occurred,” said co-author Andrea Dutton, a geoscientist and sea level expert at the University of Wisconsin–Madison. In a best-case scenario, she added, they are preparing for sea level rise at the current rate of a few millimeters per year, while the research suggests that rate will double within decades.