Kudos to 350.org for organizing the most widespread day of political action in the planet’s history. You wouldn’t know it if you get your news from the New York Times, the Huffington Post or the blogosphere but yesterday there were more than 5,200 rallies and demonstrations in 181 countries making the case that climate change must be addressed immediately and forthrightly.

The number 350 comes from a NASA research team headed by American climate scientist James Hansen, which surveyed both real-time climate observations and emerging paleo-climatic data in January of 2008. They concluded that above 350ppm CO2, the earth’s atmosphere couldn’t support “a planet similar to the one on which civilization developed and to which life on earth is adapted.” Current global CO2 concentration is at 390 parts per million.

“Glaciers and sea ice are melting, drought is spreading, and flooding is on the increase because our planet has reached a proven unsafe level of CO2 emissions,” said 350.org founder and writer Bill McKibben in New York City yesterday. “Today’s action is an example of the huge worldwide momentum we need to drive political change. Our leaders have heard from major corporations and big polluters for a long time–today, finally, they are hearing from citizens and scientists. And what they are hearing is 350.”

350.org skillfully harnessed global grassroots energy to organize the international events, employing internet tools and SMS networks, distributing lightweight Flip video cameras, and training young people in “climate camps” on multiple continents. On Saturday, organizers filmed and photographed their actions and immediately uploaded the material to the group’s website. Many of the most dramatic images were then displayed on the giant advertising screens of Times Square in Manhattan (where space was donated by the corporate owners).

Go to 350.org for more about yesterday’s historic actions and to find out how you can sign on to the global climate change movement.

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