Climate Central: On most days, Bill Dewey can be found wearing waist-high waders and inspecting Manila clams — the West Coast version of the littleneck — at his Washington clam farm, Chuckanut Shellfish. Under an arrangement that’s unique to the state, Dewey owns 32 acres of tidelands. Unlike land-based farms, he can only harvest when the tide recedes, leaving over a mile of mudflats, and shellfish, exposed. He gathers the clams with the help of a former tulip-bulb harvesting machine that’s carried out aboard his…