 Rennie wrote the blog "The Savvy Scientist" for SmartPlanet between November 2011 and September 2012 and penned a handful of articles for the General Electric sponsored online magazine, Txchnologist, in 2011 and 2012.In 2017, Rennie joined the staff of "Quanta Magazine" as a deputy editor.Rennie is listed as adjunct faculty for the graduate Science, Health and Environmental Reporting Program at New York University's Arthur L. Carter Journalism Institute.