Global Carbon Dioxide Levels Set to Pass 400 ppm Milestone
The Guardian (U.K.), April 29, 2013
The Guardian (U.K.), April 29, 2013
Yahoo Finance, April 29, 2013
U-T San Diego, April 28, 2013
U-T San Diego, April 28, 2013
U-T San Diego, April 26, 2013
Yahoo! India, April 24, 2013
KPBS, April 23, 2013
U-T San Diego, April 23, 2013
U-T San Diego, April 22, 2013
La Prensa San Diego, April 19, 2013