September 10th, 2009
(Editor’s note: For the latest development, see environmental activist Bill McKibben’s blog about climate economist Nicholas Stern adopting 350 ppm as the best target level for carbon dioxide in the atmosphere.)
By Ashley Phillips
Green Right Now
What is so significant about the number 350? It is the level scientists have identified as the safe upper limit for carbon dioxide in the atmosphere.




Barbara Kessler
Andrew Winston
Danielle Nierenberg
Anthony Swift