Coming soon on eTown: Billie Marten, one of England’s most compelling young singer-songwriters, shares songs from her latest work. Also, Portland’s Dean Johnson, who didn’t begin his music career until his fifties but has quickly become one of folk music’s most distinctive voices. Plus, eTown host Nick Forster interviews former Denver TV meteorologist Mike Nelson to discuss his book The World’s Littlest Book on Climate: 10 Facts in 10 Minutes about CO2.