350.org was founded in 2008 by a group of university friends in the United States along with author Bill McKibben, who wrote one of the first books on global warming for the general public. The goal was to build a global climate movement. 350 was named after 350 parts per million — the safe concentration of carbon dioxide in the atmosphere. Our first actions were global days of action that linked activists and organizations around the world, including the International Day of Climate Action in 2009, the Global Work Party in 2010, Moving Planet in 2011. 350 quickly became a planet-wide collaboration of organizers, community groups and regular people fighting for a fossil free future.