Joseph J. Romm (born June 27, 1960) is an American author, blogger, physicist and climate expert who concentrates on methods of reducing greenhouse gas emissions and global warming and increasing energy security through energy efficiency, green energy technologies and green transportation technologies. In December 2008, Romm was elected a Fellow of the American Association for the Advancement of Science. In March 2009, Rolling Stone magazine named Romm to its list of "100 People Who Are Changing America". In September 2009, Time magazine named him one of its "Heroes of the Environment (2009)", calling him "The Web's most influential climate-change blogger".