Rajendra Pachauri, chairman of the Intergovernmental Panel on Climate Change (IPCC) personally endorses ambitious goals to cut carbon dioxide (CO2) concentrations to below 350 parts per million (ppm). The IPCC originally reported in 2007 that woldwide CO2 concentrations must be kept below 450 ppm to prevent critical global temperature rise, however a growing body of scientific evidence suggests that concentrations must be cut even more. Read the full story here.