350 means safety from the climate crisis.
Please take time to read Mr. McKibben's artilce in Rolling Stone magazIne - same title as this posting.
Then visit 350.org to learn more about what you can do. What is 350?
To preserve our planet, scientists tell us we must reduce the amount of CO2 in the atmosphere from its current level of 392 parts per million ("ppm")to below 350 ppm. But 350 is more than a number—it's a symbol of where we need to head as a planet.
At 350.org, we're building a global grassroots movement to solve the climate crisis and push for policies that will put the world on track to get to 350 ppm.