Keywords: CO2-Mauna-Loa.png graph A graph depicting CO<sub>2</sub> levels from 1958 to 2009 as measured at Mauna Loa Hawaii Year is on the x-axis atmospheric carbon dioxide concentration in parts per million is on the y-axis The cause for the yearly rise and fall is the annual cycle of plant respiration The cause of the increasing trend is the anthropogenic release of CO<sub>2</sub> mainly due to the use of fossil energy sources Graph drawn by Hanno using data published on the web by P Tans 2007 as Monthly mean atmospheric carbon dioxide at Mauna Loa Observatory Hawaii Global Monitoring Division Earth System Research Laboratory National Oceanic and Atmospheric Administration U S Department of Commerce U S A http //www cmdl noaa gov/ccgg/trends/co2_data_mlo php Hanno Hanno Global warming graphs Mauna Loa |