. >> sreenivasan: 2014 was the hottest year on earth since susan goldberg modern record-keeping began in 1880. that is, until 2015. and then that was replaced by the hottest year on record, 2016. in advance of earth day, which occurs three weeks from today on saturday, april 22, the new edition of "national geographi"" magazine out this week, and the web site, www.natgeo.com, have published "seven things you need to know about climate change." to discuss that guide and related issues, i am joined from washington by "national geographic" editor-in-chief susan goldberg. first, why does "national geographic" feel it's necessary to do this type of a story? >> we want to do stories about climate change because "national geographic" has been doing this kind of coverage for our-- really, the entirety of our 129-year history. we've been writing about the planet and the health of the planet, animals, the environment, history, and cultures. and all of these topics are affected by what we're seeing with climate change >> sreenivasan: you're not a partisan organization. you're not trying to take