This Saturday, Oct. 24, is the big day -- across every time zone -- for 350.org . Founded to give a voice to ordinary people across the globe in advance of the U.N. climate change meeting in Copenhagen this December, the 350 campaign has been building to this Global Day of Climate Action, Oct. 24. The symbol, and the message, is a number: 350 parts per million, what scientists say is the safe limit of CO2 in the atmosphere for life to continue as human beings have known it.
We are currently at 387 and rising, 350.org  says. It won't be easy to reverse the trend, but it's not impossible. As 350.org  cofounder Bill McKibben said last month when I heard him speak at St. Philip Neri Parish  in Portland, Ore., what we need is the political will to make the necessary changes -- and political will is something millions of voices around the world can go a long way toward generating.
The day begins with a rally at dawn next to a wind turbine in New Zealand, and will move across the planet, where more than 4,000 events in 170 countries are planned. Some of the planned actions include:
- A cross-continent collaborative art project will form giant 3s, 5s and 0s.
- Churches have agreed to ring their bells 350 times.
- Villagers in a remote, drought-stricken region of Somalia will demonstrate 350 solar cookers.
- In Bolivia, indigenous Aymara shamans will hold a ceremony where the glacier Chacaltaya disappeared earlier this year.
- Palestinians, Jordanians and Israelis will form a trans-boundary 350 on the shore of the shrinking Dead Sea.
- Hundreds of citizens of the endangered island nation of the Maldives will form an underwater 350. (Last week, the Maldives' President Mohamed Nasheed held a cabinet meeting underwater to sign a declaration calling for action on climate change.)
When I heard McKibben talk about 350.org, I knew I wanted to be a part of this moment. So I'll be joining the rally here in Kansas City, Mo. Want to join in? You can find a local action by going to 350.org/action-list  and entering your city into the search.