The Keeling Curve A daily record of atmospheric carbon dioxide from Scripps Institution of Oceanography at UC San Diego

The Scripps CO2 measurements at Mauna Loa have been supported for many years by the U.S. Department of Energy (DOE), and have more recently been supplemented by Earth Networks, a technology company that is collaborating with Scripps to expand the global GHG monitoring network. Support for website development was provided in part by the National Science Foundation (NSF). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of NSF.

Note on Reaching the Annual Low Point

September 23, 2016 Rob Monroe

We are now approaching the annual low point in the Mauna Loa CO₂ curve, which typically happens around the last week of September but varies slightly from year to year.

Brief Reprieve from 400 PPM Era May Be Thanks to a Hurricane

August 31, 2016 Rob Monroe

A hurricane bearing down on Hawaii prompted operators to shut down CO₂ monitoring equipment at Mauna Loa Observatory on the Big Island.

Daily Readings Have Been Restored

June 21, 2016 Rob Monroe

A failed disk that had prevented the reporting of daily readings was replaced on June 14 and the system is now running normally.

Note on Pause in Daily Readings

June 14, 2016 Rob Monroe

Readings of CO2 from Mauna Loa have been unavailable for two weeks.

According to technicians with the Scripps CO2 Group, the problem is a disk failure that handles the data buffering, which has broken the data stream and valve switching that impacts daily calibration. The air data are recoverable, because the computer onboard the actual instrument is still working and taking air data, but we will need to assess the stability of calibration once the instrument is working completely again. A replacement was shipped last week, so it should be up again shortly.

– Robert Monroe

Why Has a Drop in Global CO2 Emissions Not Caused CO2 Levels in the Atmosphere to Stabilize?

May 23, 2016 Rob Monroe

Note: Readers have asked why there has been no stabilization in the measured levels of the greenhouse gas carbon dioxide in the atmosphere when reported emissions of CO₂ have fallen. Scripps CO₂ Group Director Ralph Keeling gave this response: