From 350.org:

About 350

Where do we go from here? Our first step is to wean ourselves from coal and oil and we have to do it while still allowing the poor parts of the world to develop. We can do this by creating a global clean energy economy that is strong enough to lift the world’s poor out of poverty. It won’t be easy, and there are many possible approaches. We need to act swiftly, however—this is the greatest crisis human civilization faces.

350 is the red line for human beings, the most important number on the planet. The most recent science tells us that unless we can reduce the amount of carbon dioxide in the atmosphere to 350 parts per million, we will cause huge and irreversible damage to the earth.

But solutions exist. All around the world, a movement is building to take on the climate crisis, to get humanity out of the danger zone and below 350. This movement is massive, it is diverse, and it is visionary. We are activists, scholars, and scientists. We are leaders in our businesses, our churches, our governments, and our schools. We are clean energy advocates, forward-thinking politicians, and fearless revolutionaries. And we are united around the world, driven to make our planet livable for all who come after us.

We are everywhere, and together we are unstoppable.

Our Mission:

Our first job is to make sure everyone knows the target so that our political leaders feel real pressure to act. Reaching 350 ppm will require unprecedented international cooperation. The United Nations is negotiating a treaty that could put the world on a course to solve the climate crisis, but the current plans for the treaty are much too weak to get us back to safety. 350.org will bring millions of new voices to the table, united by our common call to action. Together, we will redefine the possible and rally the world behind the solutions that science and justice demand.

Join us today.

Our Vision:

Where do we go from here? Our first step is to wean ourselves from coal and oil and we have to do it while still allowing the poor parts of the world to develop. We can do this by creating a global clean energy economy that is strong enough to lift the world’s poor out of poverty. It won’t be easy, and there are many possible approaches. We need to act swiftly, however—this is the greatest crisis human civilization faces.

Read more and learn what you can do at 350.org