The semi-annual Sing Out special “Accordions Save the World” presents two hours of the world’s greatest accordion recordings — from every continent, from Italy to Madagascar, from rock to classical, from Rolling Stones to Kronos Quartet — as a salute to the 23rd Cotati Accordion Festival (Aug. 17-18). Hosted by Larry Kelp, whose first instrument was the accordion, and who believes that accordion music can save humanity from global catastrophe.