That oceanfront property in Stinson Beach you’ve dreamed about may not be so perfect after all. A report published Monday finds that nearly 4,400 homes in Marin County might not make it beyond a 30-year mortgage because of encroaching seawater. According to the publication by the Union of Concerned Scientists, Marin County leads the state in the number of parcels that could literally be underwater by 2045 because of climate-driven sea level rise. Across California, more than 20,000 homes are at risk.