350 DAY: October 24 has been dubbed a day of action worldwide to push for returning greenhouse gas levels to 350 parts per million in the atmosphere.
Courtesy of 350.org

Author Bill McKibben never saw this coming. Founder of 350.org, an environmental campaign aimed at holding atmospheric carbon dioxide concentrations below 350 parts per million, McKibben sent word that this Saturday would be the day to take to the streets.

The call went viral in ways far beyond anything McKibben and fellow organizers imagined: As of Thursday morning some 4,317 actions and rallies are planned in 171 countries, with 300 events in China, 1500 across the United States, 500-plus in Central and South America.

Organizers credit the increasing inter-connectedness of Web, cellular and social networks for the spread, saying such random and organic growth would have been impossible even two years ago.

The climate crisis is also starting to resonate in a significant way, McKibben added. This is arguably the largest political event ever to take a data point as a rallying cry, he said, and people—particularly the youth behind many of the actions planned for Saturday—get it.

"This is the one most important number in the world right now," McKibben said in an interview. "It's the one number that applies as absolutely in the Maldives as in Manhattan. It somehow has worked its magic."

* On the shores of the dwindling Dead Sea, Israeli activists will make a giant human "3" on their beach, Palestinians a huge "5" on their shore and Jordanians a "0" on theirs.
* In the coup-ridden capital of Honduras, parishioners of the Amor, Fe, y Vida church will host a neighborhood tree-planting while across town activists plan a 5-kilometer march.
* Up in Canada's Yukon Territory, a Whitehorse youth group is planning a group hug—350 people strong—of the territorial legislature.
* With a nod to folk singer Pete Seeger, Greenfield, Mass.' Amandla Chorus has reworked the lyrics to Beethoven's classic Ode to Joy and will perform their version at the town 350 Day festival.
* An energy group is throwing a black-tie gala in Shanghai; in Beijing a few hundred students intend to cycle through downtown; way out in Western China a handful of students plans to hike to a melting glacier.

"We were prepared for a great day in the United States," said Jamie Henn, 350.org's coordinator, who organized China with a visit, some emails, a few calls and a bunch of instant message "chats." "We had no idea it would take off the way it has internationally."

"The great thing about these digits (3-5-0) is that you can recognize them no matter what script you're using," he added. "It goes to show how wired the world is in many ways, and how you can take a real simple and focused bit of information and broadcast it around the world."

The number stems from the amount of planet-warming carbon dioxide scientists believe the atmosphere can safely hold before climate systems start to go haywire.

For the millennia before the industrial revolution, when humans started pumping industrial emissions into the atmosphere, carbon dioxide levels had held fairly steady at about 280 ppm. Carbon dioxide concentrations rose gradually but steadily to the mid-20th century, when they started to skyrocket. Today the level is 387 ppm, with many analysts expecting the globe to hit 450 ppm or even 550 ppm before world economies "decarbonize" sufficiently to radically reduce emissions.

The problem is that data from the past 100 million years suggests the planet was largely ice-free until carbon dioxide levels fell below 450 ppm, plus or minus 100 ppm. Somewhere between 350 ppm and 550 ppm, climatologists suspect, is a critical threshold that triggers irreversible climate change, loss of major ice sheets, abrupt sea-level rise and massive shifts in forests and agriculture.

Until recently the notion of bringing atmospheric carbon dioxide levels back to 350 ppm—voiced most vocally by McKibben and NASA's Jim Hansen—was dismissed as wild-eyed optimism. The Earth last saw 350 ppm in 1987, when President Reagan was in office; the molecule hangs in the atmosphere for centuries; and the world's major industrialized economies so far have shown little ability—to say nothing of inclination—to turn off the tap.