Scientists estimated global average carbon dioxide concentration at 397.2 parts per million (ppm) in 2014, as the global growth rate of carbon dioxide continues to accelerate. 

Montzka in a snow pit in Antarctica

Some of the chemicals that replaced ozone-harming CFCs are long-lived greenhouse gases. At NOAA's lab in Boulder, Colorado, chemist Steve Montzka leads the effort to monitor the concentration of CFC-substitutes and their potential impact on global warming.

Charles Keeling's measurements of carbon dioxide from the summit of Mauna Loa have become a landmark for mankind’s impact on the Earth. In this video, NOAA scientists talk about the history of the observations that allow us to connect Earth's warming climate to the greenhouse gases from burning fossil fuels.

Decision Maker's Toolbox Annual Greenhouse Gas Index

Since 2004, researchers in NOAA’s Global Monitoring Division have released the Annual Greenhouse Gas Index: a single value that compares the total warming effect of each year's concentrations of heat-trapping gases to 1990 levels.

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