Today the concentration of CO2 in our planet's atmosphere is 390 ppm, say the organizers of 350.org, a group that called for an international action on October 24th. They helped organize more than 5,200 rallies in 181 countries, calling it the most widespread day of political action in history. In countries throughout the world activists called for a reduction of CO2 to a maximum of 350 ppm, and in Northern California residents in many of the state's diverse micro-climates took part in the big day.

In Santa Cruz, marchers carried placards through town to the clock tower where they held a mock trial of the automobile. In Humboldt County, demonstrators chose the ancient redwood forest in Richardson Grove as their site for protest because it is threatened by Caltrans’ proposal to widen highway 101. In San Francisco, folks spread a giant 350 banner across Justin Herman Plaza to call attention to this important number.

In Menlo Park, a San Francisco peninsula suburb, the Raging Grannies sang their message, saying the trick is getting leaders to craft policies that will get us to the number 350. In addition to lobbying politicians, the Grannies have joined a year-long project led by Menlo Park's Green Ribbon Committee to promote homeowner installation of "cool roofs" that, because they are white or other light colors, can help protect the earth's atmosphere.

Photos: 1 | 2 | 3 | 4 | 5 | Video | 350.org