A 50-year plan now in the works could change zoning rules and real estate development goals for the seven costal counties stretching from Key West to the Indian River Lagoon.

Seven50, a long-term plan for economic and civic growth in seven southeast Florida counties, is a proposal from the South Florida and Treasure Coast regional planning councils. Proponents say it anticipates rising sea levels, the projected influx of 3 million-plus new residents and other issues the region will face in coming decades.