A view of downtown Boise, Idaho. —4kodiak—Getty ImagesThe water in Charleston does not flow through the city as a policy debate. It comes gushing over curbs, through intersections, around school buses and storefronts. The city sits at sea level, and the sea is rising. For years, Charleston flooded, recovered, and waited for the next storm. What changed was not the weather, but participating in the Bloomberg Harvard City Leadership Initiative and…