Mauna Loa Observatory, Hawaii (USA) Atmospheric CO2 was 387.27 parts per million (ppm) in the last month of 2009, according to scientific data released January 7, 2010, by the National Oceanic and Atmospheric Administration (NOAA) in the United States. Atmospheric CO2 was 385.54 ppm one year earlier in December 2008.
The 2009 annual mean concentration of CO2 in the atmosphere was 387.35 ppm, up from 385.57 ppm in 2008.
These rising levels are significantly higher than the natural range (~180 ppm to 300 ppm) that existed for at least 2.1 million years until the start of the industrial revolution. [reference]
Carbon dioxide (CO2) is the chief human-made greenhouse gas that fuels global warming, climate change and ocean acidification. The main anthropogenic source of CO2 emissions is the use of fossil fuels for energy. Atmospheric CO2 levels continue to rise with on a year-over-year basis because carbon emissions from human sources exceed the capacity of the land and oceans to absorb it. The absorbtion of CO2 by oceans is a natural process that both slows the rate of global warming and puts damaging quantities of carbonic acid in the oceans. The most direct thing that people can do is make decisions and take actions that actually reduce and eliminate the addition of more invisible CO2 into the atmosphere.