Weekly means for atmospheric CO2 originate from the NOAA Earth System Research Laboratory (ESRL) and its Mauna Loa Observatory in Hawaii.


Weekly CO2

  Mauna Loa Observatory | NOAA-ESRL



Atmospheric CO2

Last Week

March 21 - 27, 2021

417.67 ppm

1 Year Ago

March 21 - 27, 2020

415.67 ppm

10 Years Ago

March 21 - 27, 2011 

393.61 ppm

  Data Updated:  March 29, 2021
  NOAA dataset: Web + .txt

weekly mean concentrations  |  ppm = parts per million


NOAA-ESRL and Scripps CO2 provide continually-updated graphics with daily and weekly data points plotted over multiple time periods.  Use the tabs below to view these graphics as well as links to the NOAA and Scripps websites.  The CO2 Earth Records page tracks the latest weekly record-high CO2 levels

Recent data is preliminary.  NOAA-ESRL is the only weekly dataset with values updated in real time.  Scripps CO2 posts a weekly CO2 dataset that is updated less frequently.


CO2 Past.  CO2 Present.  CO2 Future.