Sharp rise in CO2 levels recorded By David Shukman BBC science correspondent Scientists fear high carbon levels will trigger sudden changes US climate scientists have recorded a significant rise in the concentration of carbon dioxide in the atmosphere, pushing it to a new record level. BBC News has learned the latest data shows CO2 levels now stand at 381 parts per million (ppm) - 100ppm above the pre-industrial average. The research indicates that 2005 saw one of the largest increases on record - a rise of 2.6ppm. The figures are seen as a benchmark for climate scientists around the globe....