The rate of sea level rise is incremental, typically measured in millimeters per year. But Pat Neild has lived long enough to witness how those millimeters have added up. “In my lifetime, which is 94 years now, the sea level has come up at least a foot, maybe 18 inches,” said Neild, the owner of a large grain farm on Maryland’s Eastern Shore that is slowly being overtaken by the Chesapeake Bay. “I can tell that by the land that we can’t till anymore.”