LI‑COR Analyzers Monitoring Carbon Dioxide Worldwide as Atmospheric Levels Reach 400 parts per million

May 15, 2013

On May 13, the National Oceanic and Atmospheric Administration (NOAA) reported a preliminary daily average carbon dioxide (CO2) reading of 400.07 parts per million (ppm) at the Mauna Loa Observatory on the Big Island of Hawaii.

On May 9, a reading over 400 ppm was reported at the site for the first time ever. But that reading (400.03 ppm) was later revised to 399.89 ppm. The first CO2 measurement at the observatory was 313 ppm in 1958. According to the Scripps Institution of Oceanography, these measurements—known as the “Keeling Curve”—make up the world's longest unbroken record of atmospheric CO2 concentrations. The Keeling Curve, with its steady upward slope, has been used to show a relationship between increased fossil fuel burning and increasing atmospheric CO2 levels.

Charles David Keeling established CO2 monitoring at the Mauna Loa Observatory using high-precision infrared gas analyzers. Today, the LI‑7000 CO2/H2O Gas Analyzer—manufactured by LI‑COR Biosciences in Lincoln, Nebraska—is one of the instruments used at Mauna Loa. At their Earth Systems Research Laboratory in Boulder, Colorado, NOAA also uses the LI‑7000 for analyzing flasks of air collected from more than 60 sites around the world. These data are used to populate global models and understand changes in atmospheric CO2 concentrations over time. The lab receives 15,000–20,000 flasks for analysis each year. In addition, LI‑COR's gas flux measurement systems are helping researchers study greenhouse gas emissions and global climate change. LI‑COR CO2/H2O analyzers are used in over 90% of CO2 flux towers worldwide, to identify and quantify sources and sinks of greenhouse gases.

The Mauna Loa Observatory includes two CO2 monitoring programs; one by NOAA and the other by the Scripps Institution of Oceanography. CO2 readings and background information can be found at or Details about NOAA's flask sampling program are at

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