A year ago, we learned that if we let the amount of carbon in the atmosphere go above 350 parts per million, we can't have a planet "similar to the one on which civilization developed and to which life on earth is adapted."

The bad news: We're already past that number – we're at 390 parts per million!

The good news: That number gives us a target to aim for. When the world's leaders meet in Copenhagen in December to reach agreement on a new climate treaty, we need them to make sure they'll put forward a plan that gets us back to safety.

On October 24, people in more than 4227 communities around the globe will be taking action in 170 countries under the banner of 350.org.

The 350.org website has a wealth of information, including this fact sheet on Food & Climate which encourages folks to "Go organic: If everyone converted 10% of their diet to organic, we could capture an addition 6.5 billion pounds of carbon in the soil – the equivalent of taking 2 million cars off the road each year!"

Here's a video from the 350.org in DC: