From 350.0RG: 350 parts per million is what many scientists, climate experts, and progressive national governments are now saying is the safe upper limit for CO2 in our atmosphere.

Accelerating arctic warming and other early climate impacts have led scientists to conclude that we are already above the safe zone at our current 390ppm, and that unless we are able to rapidly return to 350 ppm this century, we risk reaching tipping points and irreversible impacts such as the melting of the Greenland ice sheet and major methane releases from increased permafrost melt.

There are three numbers you need to really understand global warming, 275, 390, and 350.

For all of human history until about 200 years ago, our atmosphere contained 275 parts per million of carbon dioxide. Read more (by Bill McKibben)>>>>

350.org is calling on people around the world to organize an action on October 24 incorporating the number 350 at an iconic place in their community, and then upload a photo of their event to 350.org website.

Video about 350.org: