How to rally a global climate movement? That’s the question the heros at take up in this video highlighting the 4,641 global actions currently planned for tomorrow, Saturday, October 24.

A year ago, NASA’s James Hansen and his team produced a landmark series of studies. They showed that if the amount of carbon in the atmosphere tops 350 parts per million, the planet “similar to the one on which civilization developed and to which life on earth is adapted” will be perhaps irreversibly harmed.

The bad news is we’re already past that number–we’re at 390 parts per million, which is why the Arctic is melting, why drought is spreading across the planet, why people are already dying from diseases like dengue fever and malaria occurring in places where they’ve never been seen before. The good news is that there’s a growing global awareness of the urgency of the problem and groups like mobilizing an international movement.

Tomorrow’s series of international actions promises to be the largest climate action the world has ever seen, as this interactive world map suggests.

They’ll be school children planting 350 trees in Bangledesh, scientists hanging banners saying 350 on the statues on Easter Island, 350 scuba divers diving underwater at the Great Barrier Reef, and thousands of other creative actions.

“We encouraged lots of different groups to join,” May Boeve, a partnerships director told The Guardian. “We’ve cast a very large net.” Those groups will include churches, performance artists, extreme athletes, and a Chinese businessman holding a black-tie gala in Shanghai.

At each event, people will gather for a big group photo that somehow depicts 350–and upload that photo to the web As actions take place around the world, all the pictures will be linked together electronically, offering what should be a powerful visual petition linking together the entire planet. A photo has even come from troops in Afghanistan.

These actions are focused on convincing the world’s leaders to reach agreement on a new climate treaty when they meet in Copenhagen in December.

Find an event near you, help spread the word about and support the group’s upcoming campaigns.

PS: If you have extra time on your hands and want to follow me on Twitter — a micro-blog — click here. You’ll find (slightly) more personal posts, breaking news, basketball and lots of links.