If you've ever tried to tell people about 350.org, you've probably heard this question before: "What's 350?" No, it's not "almost a circle" or a popular baking temperature, you've had to answer. It stands for 350 parts per million. That's the safe level of CO2 in the atmosphere according to the latest science. 

Thanks in large part to all the great organizing you've done around the world, more and more people are seizing onto this 350 target as a simple, scientific way to explain the climate challenge we face.

Today, the New York Times published a front-page story all about the history of "parts per million" and the scientist who first started measuring the concentration of greenhouse gases in our atmosphere. The article begins: 

MAUNA LOA OBSERVATORY, Hawaii — Two gray machines sit inside a pair of utilitarian buildings here, sniffing the fresh breezes that blow across thousands of miles of ocean.They make no noise. But once an hour, they spit out a number, and for decades, it has been rising relentlessly.
(That's a picture of some 350.org supporters at Mauna Loa itself during a day of action).
Take a few minutes to read through the article and share it with family and friends — what better time to discuss climate change then over the holidays, right?. It's a great chance to brush up on your basic climate science and become more familiar with the story of "ppm." 
Of course, by joining this movement, you've become a part of this story as well. Because just as the amount of CO2 steadily ticks upwards at Mauna Loa, so too does the number of people joining this "people powered movement." Now that's a "ppm" we can get excited about. 
Click here to read the rest of the article in the New York Times. 

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