For reference, we are currently at approximately 394 ppm [0] [0]http://www.esrl.noaa.gov/gmd/ccgg/trends/global.html http://www.esrl.noaa.gov/gmd/ccgg/trends/g

For reference, we are currently at approximately 394 ppm [0] [0]http://www.esrl.noaa.gov/gmd/ccgg/trends/global.html http://www.esrl.noaa.gov/gmd/ccgg/trends/global.html