If you eat a lot of farm-raised beef and then start getting all those calories from chicken instead it will indeed be a significant reduction of your carbon foo

If you eat a lot of farm-raised beef and then start getting all those calories from chicken instead it will indeed be a significant reduction of your carbon footprint. If you give up air travel, while you're at it, you might cut it just as much again, or more. (depending, of course, on how much you fly).