Organizing around one goal: reducing carbon dioxide in the atmosphere.How low can you go? That's the question environmentalists will be asking world leaders when they gather in Copenhagen, Denmark, in December to hash out a new global climate treaty mandating how drastically countries will slash their greenhouse gas emissions. Galvanized by NASA scientist James Hansen, a growing number of advocates are pushing an ambitious target: 350 parts per million, which they say is the maximum concentration of carbon dioxide we can support in our atmosphere if we want to prevent the most catastrophic effects of climate change.Carbon particles trap heat from the sun, causing a cascade of threats to Earth: the melting of glaciers, an increase in droughts, and possibly the spread of mosquito-borne disease. The atmosphere currently contains 385 ppm of CO2-and that number is climbing. The Intergovernmental Panel on Climate Change has identified a higher-and more politically feasible-450 ppm cap to stop global warming.Budding environmental scientist Ryan Hottle, 26, decided he wouldn't wait for the meeting in Copenhagen. "We're not moving fast enough right now to avoid dangerous and potentially catastrophic climate change," he says. With a group of fellow students at Columbia University and $4,000 from its climate and society program, Hottle held a 350 conference in May that attracted, fittingly, 350 academics and concerned citizens. In addition to scientists, like Hansen, the Columbia conference featured Majora Carter of the environmental justice group Sustainable South Bronx and Kevin Conrad, environmental ambassador for Papua New Guinea, both voices that, Hottle notes, "often get left out of these very scientific conferences."Other consciousness-raising events are being organized by the 350.org campaign-which inspired Hottle's efforts. On October 24, community activists around the world will stage activities about the Copenhagen summit, the 350 ppm emissions target, and alternative energy sources (like wind and solar power) that could make it a reality. Says Hottle: "You hope momentum builds to say, ‘Hey, we can't shoot for 450. We may have to look to more robust ways to cut carbon emissions.'"Return to interactive site

---