Annual CO2

Atmospheric CO2 Concentrations
Mauna Loa Observatory (MLO) & Global

NOAA-ESRL
MLO

SCRIPPS UCSD
MLO (*)

Year

NOAA-ESRL
Global

400.83 ppm

400.88 ppm 2015 399.47 ppm

398.61 ppm

398.61 ppm

2014

397.16 ppm

396.48 ppm

396.57 ppm

2013

395.25 ppm

393.82 ppm

393.87 ppm

2012

392.48 ppm

May 5, 2016
May 4, 2016
latest update
May 5, 2015
.txt + web
.csv + web (*)
source datasets
.txt + web

annual mean concentrations  |  ppm = parts per million

* Annual values for Scripps are calculated by CO2.Earth as a
12-month average of Scripps monthly mean concentrations.

 

The direction of atmospheric CO2 has been constant for decades.  Year after year since 1958 when Charles David Keeling started measurements at the Mauna Loa Observatory in Hawaii, earth's background CO2 level has only gone up.   Overall, the increases have been accelerating.

The Mauna Loa Observatory is home to two independent CO2 monitoring programs:

  • April 1974 - Present  Global Monitoring Division | National Oceanic and Atmospheric Administration (NOAA) Earth System Research Laboratory (ESRL)
  • 1958 - Present  Scripps CO2 Program | Scripps Institution of Oceanography (SIO) at the University of California San Diego (UCSD)

NOAA operates the Mauna Loa facility.

 

Citing the Current Global Average

 

Two common ways exist for citing current global average concentrations of CO2 in the atmosphere.  One uses the annual average concentration measured at one location, the Mauna Loa Observatory (MLO).  The other uses an annual 'spatial' average of globally-averaged marine surface data from the NOAA-ESRL cooperative air sampling network.  The MLO average is considered a good approximation although the data above shows that it is typically about 1.4 ppm aove the spaial average. (Citing global averages is discussed by T.J. Blasing at footnote 7 of the CDIAC update for recent GHG concentrations.)

 

 

CO2 Past.  CO2 Present.  CO2 Future.