Founded and led by Bill McKibben, 350.org is an international campaign to promote global environmentalism and to generate support for intergovernmental regulations on greenhouse-gas emissions. The group derives its name from the measurement "350 parts per million" (350 ppm), which some scientists believe is the maximum amount of carbon dioxide (CO2) that should be permitted to exist in the earth's atmosphere. The leaders of 350.org contend that if the benchmark of 350 ppm is not reached in the near future, a global catastrophe will result. Indeed, 350.org maintains that many harbingers of such a cataclysm are already evident: polar icecap melting, worldwide increases in disease, food shortages, and general environmental degradation.
Especially important to the mission of 350.org was the work of Dr. James Hansen, head of the NASA Institute for Space Studies in New York City. Hansen, who is a 350.org "messenger," has worked to promote the idea that 350 ppm is a necessary carbon-dioxide ceiling. Much of 350.org’s activity is designed to make the “350” number, and by extension its environmental significance, a universally recognizable meme.
350.org vehemently opposes the use of fossil fuels, particularly oil and coal. Likewise, the organization opposes off-shore oil drilling. In the wake of the massive 2009 Gulf Coast oil spill, 350.org launched a campaign to protest off-shore drilling and the use of fossil fuels in general.
Most of 350.org’s ongoing campaigns are geared toward organizing concerted events and demonstrations around the world. This is especially true in advance of landmark global-warming conferences such as the 2009 global-climate summit in Copenhagen. In an effort to generate public support for the summit within the faith community, 350.org partnered with the World Council of Churches to enlist houses of worship in numerous countries to ring their bells 350 times during the weekend of December 11-13, 2009, while the Copenhagen conference was in session. Notable participants in this bell-ringing initiative included Archbishop Desmond Tutu of South Africa and the Archbishop of Canterbury, Rowan Williams. In addition, 350.org collaborated with such luminaries as Tutu and Avaaz.org executive director Ricken Patel to organize a candlelight vigil promoting the Copenhagen talks.
But the celebration did not last long, once it became clear that President Obama had left the door open to the possibility that the Keystone proposal might eventually pass regulatory muster. Outraged, 350.org vowed to protest every subsequent public appearance by Obama until such time as he announced a final decision regarding the pipeline.