Yale Environment 360: As atmospheric concentrations of carbon dioxide approach the milestone of 400 parts per million (ppm), a scientist at the Scripps Institution of Oceanography has launched a Website that will publish daily readings of CO2 concentrations, an online resource he hopes will drive home the urgent threat of rising greenhouse gas emissions. Ralph Keeling, director of the Scripps CO2 program and son of the first scientist to measure CO2 concentrations, hopes the daily tracker will attract more attention than...