On This Week’s Record High CO2 Readings at Mauna Loa

Robert MonroeDaily Measurements, Measurement Notes

Mauna Loa Observatory. Photo: NOAA

On Saturday, Feb. 3, the daily Keeling Curve record was broken when instruments at Mauna Loa detected a carbon dioxide concentration of 426.5 parts per million (ppm). It was the first time in the modern record a daily reading had exceeded 425 ppm, though the annual peak does not typically take place until May. Since then, several daily readings have surpassed 425 ppm.

The reading was also an increase of more than 4 ppm from the previous day’s. Scripps CO2 Program Director Ralph Keeling said that a shift in weather patterns played a role.

“We attribute the large increase in CO2 that occurred from Feb. 2 to Feb. 3 to a strong wind shift, as a new weather system moved in,” Keeling said.  “Before this weather shift, the Mauna Loa Observatory was receiving air that had blown in from lower latitudes.  After the shift, the air was coming from northern latitudes, where CO2 is normally higher this time of year.  An upwards shift in CO2 was therefore to be expected.”