Activists Rally Around the World to Mark 'Magic' Climate Change Number

Activists held events around the world Saturday to mark the number they say the world needs to reach to prevent disastrous climate change: 350.

The number represents 350 parts per million of carbon dioxide emissions in the atmosphere that some scientists say is the safe upper limit. The atmosphere currently reaches about 390 parts per million, according to research by NASA climate scientist James Hanse cited by 350.org.

Activists held events around the world Saturday to mark the number they say the world needs to reach to prevent disastrous climate change: 350.
The number represents 350 parts per million of carbon dioxide emissions in the atmosphere that some scientists say is the safe upper limit. The atmosphere currently reaches about 390 parts per million, according to research by NASA climate scientist James Hanse cited by 350.org.