CO2 Now


What the world needs to watch

Global warming is mainly the result of CO2 levels rising in the Earth’s atmosphere. Both atmospheric CO2 and climate change are accelerating. Climate scientists say we have years, not decades, to stabilize CO2 and other greenhouse gases.

To help the world succeed, makes it easy to see the most current CO2 level and what it means. So, use this site and keep an eye on CO2.  Invite others to do the same. Then we can do more to send CO2 in the right direction.

Watch CO2 now and know the score on global warming, practically in real time.

CO2 Now
Scripps CO2 Data - Mauna Loa Observatory PDF Print E-mail

Scripps Institution of Oceanograph

This page presents data for atmospheric CO2 measurements by the Scripps CO2 Program at the Mauna Loa Observatory in Hawaii.   Starting March 1958, the Scripps Mauna Loa data is the longest-runing, high-precision instrument record for atmospheric CO2. 

About the Scripps CO2 Program

The Scripps CO2 program was initiated in 1956 by Charles David Keeling who directed the program until he died in 2005.  The program is now operated by  Ralph F. Keeling who also runs the Scripps O2 Program that measures atmospheric oxygen and argon.   Both programs are based at the Scripps Institution of Oceanography in San Diego (La Jolla) California.


Scripps Data

Source Update:  June 4, 2015:

CO2Now Documents:        Scripps CO2 Data        Scripps CO2 Data    

Scripps CO2 Program:      Scripps Source CO2 Data (CSV) 


Scripps Program

Scripps CO2 Program Home Page | Scripps CO2 Program


More from the Scripps CO2 Program

Keeling Curve Website  |  See the most recent daily average for atmospheric CO2

Keeling Curve Twitter  |  Daily averages for atmospheric CO2 (recent and historical)




NOAA CO2 Data |

Earth's CO2 Home Page PDF Print E-mail

CLICK HERE for daily CO2Now data updates.






Atmospheric CO2 for September 2015

preliminary monthly average

Mauna Loa Observatory (NOAA-ESRL)


NOTE:  On May 10, 2013, NOAA & Scripps first reported daily averages that temporarily reached 400 ppm.

Atmospheric CO2 data and trend  

CO2 Data Set:

Original CO2 data files dated:  Monday October 5, 2015 (NOAA)

Measuring Location:

Mauna Loa Observatory, Hawaii


Why is CO2 significant?
Carbon dioxide (CO2) is the chief greenhouse gas that results from human activities and causes global warming and climate change. To see whether enough is being done at the moment to solve these global problems, there is no single indicator as complete and current as the monthly updates for atmospheric CO2 from the Mauna Loa Observatory.
What is the current trend?
The concentrations of CO2 in the atmosphere are increasing at an accelerating rate from decade to decade.   The latest atmospheric CO2 data is consistent with a continuation of this long-standing trend.
What level is safe?
The upper safety limit for atmospheric CO2 is 350 parts per million (ppm). Atmospheric CO2 levels have stayed higher than 350 ppm since early 1988.


This atmospheric CO2 is one of four planetary boundaries that have been surpassed.   Read more about the earth's climate boundary and others at the Stockholm Resilience Centre.


Current Data for Atmospheric CO2 PDF Print E-mail

The world's most current data for atmospheric CO2 is measured at the Mauna Loa Observatoy in Hawaii.  Measurements are made and reported independently by two scientific institutions:  Scripps Institution of Oceanography and the National Oceanic and Atmospheric Administration (NOAA).  Monthly data is posted below.   

Mauna Loa CO2 Data Sets:

    Monthly     NOAA CO2 Data
    Weekly        NOAA CO2 Data

    Monthly    Scripps CO2 Data
Scripps CO2 Data

NOAA Mauna Loa CO2 Data PDF Print E-mail


NOAA release date for monthly CO2 data:

September 7, 2015 

Atmospheric CO2
Mauna Loa Observatory (Scripps / NOAA / ESRL)
Monthly Mean CO2 Concentrations (ppm)
Since March 1958


The monthly MLO data set is reposted by in 2 formats:

 NOAA CO2 Data for the Mauna Loa Observatory     PDF Version 

Source Data

Mauna Loa Monthly Mean CO2

Source data published by the National Oceanic and Atmospheric Administration (NOAA)

Mauna Loa Annual Mean CO2

Source data published by the National Oceanic and Atmospheric Administration (NOAA)


Data Notes

  • At, data for March 1958 - April 1974 was obtained by Charles David Keeling of the Scripps Institution of Oceanography (Scripps).  Data for CO2 since May 1974 was obtained by the National Oceanic and Atmospheric Administration (NOAA).   The Scripps Institution of Oceanography also maintains a CO2 monitoring program at the Mauna Loa Observatory.  Click here to access the Scripps data for the Mauna Loa Observatory.   
  • Monthly mean CO2 concentrations are determined from daily averages for the number of CO2 molecules in every one million molecules of dried air (water vapor removed).  Annual mean CO2 concentrations are the arithmetic mean of the monthly averages for the year.  Atmospheric CO2 concentrations are expressed as parts per million (ppm).


  • NOAA data published within the past year is preliminary and subject to change by NOAA due to its recalibration of the reference gas mixture used or other quality control procedures.  In some cases, data from earlier years may be changed for the same reasons.  Usually, these changes are minor. See the NOAA change log and notes that was started in August 2008 to keep a public record of the adjustments and reasons for the adjustments.   


  • All data in this table is republished from the most current data available from NOAA.  Data is republished independently by Pro Oxygen at to make it easier for people to see the latest atmospheric CO2 data and trend information.  A delay of 4 to 24  hours typically occurs between the release of monthly data by NOAA and the publication of updates at   The accuracy of republished data can be checked by reviewing the source data.   In the event that a publication error is detected, please send details to This e-mail address is being protected from spam bots, you need JavaScript enabled to view it .   



More Data



CO2 Acceleration  |

Mauna Loa Science and Wonder  |

The CO2Now Climate Sheet PDF Print E-mail

The Climate Sheet

Data current as of January 19, 2014

Climate Sheet posts the world’s most current and important planetary data and targets – together in one place from leading global sources.  The CO2Now Climate Sheet enumerates the chain of causes that are driving humanity’s largest environmental crises – global warming, climate change and ocean acidification.  It also sets out key scientific markers for a stable climate system.

Mauna Loa CO2 Board PDF Print E-mail

The Most Current CO2 Data on Earth | October 2015

Atmospheric CO2  |  Mauna Loa Observatory

NOAA-ESRL  |  Data available since 1974

Scripps CO2 Program  |  Data available since 1958


Latest Data



Last Update 


click here or here

397.55 ppm

October 3 2015**

395.04 ppm

October 4 2014


Scripps CO2

October 5 2015


click here

396.24 ppm

October 5 2015**

no comparison

is available

for 2014


October 6, 2015



397.20 ppm

September 27 - October 3 2015

395.34 ppm

September 27 - October 3 2014


October 5 2015

also see historical Scripps weekly CO2 data here


398.60 ppm

August 2015

397.22 ppm

August 2014

Scripps CO2

September 5  2015


397.64 ppm

October 2015

395.26 ppm

October 2014



October 5, 2015


398.60 ppm*


396.52 ppm*


Scripps CO2

June 4, 2015


398.55 ppm


396.48 ppm



September 7, 2015

* Scripps annual CO2 data is calcuated by CO2Now using Scripps monthly CO2 data.
** Averages determined by Scripps and NOAA cover a different 24-hour time period due to time zone differences. 


Atmospheric CO2    |  Global Data

NOAA-ESRL Cooperative Air Sampling Network 

Global Data Available Since 1980


Latest Data 


Last Update 


396.86 ppm 

August 2015

394.79 ppm 

August 2014

October 5, 2015


397.15 ppm 


395.22 ppm 


October 5, 2015



Weekly Data | Atmospheric CO2 PDF Print E-mail

September 2015

Atmospheric CO2  - Weekly Data
Mauna Loa Observatory   |   NOAA-ESRL Data


Atmospheric CO2 

Sept. 27 - Oct. 3, 2015

397.20 ppm

(last week)

Sept. 27 - Oct. 3
, 2014



(1 year ago)


Sept. 27 - Oct. 3, 2005


376.49 ppm

(10 years ago)


Atmospheric CO2  -  Increase Since 1800
Mauna Loa Observatory   |   NOAA-ESRL Data

As of Last Week

Increase Since 1800 

Sept. 27 - Oct. 3, 2015

+ 120.80 ppm

NOAA-ESRL updated weekly data on October 5, 2015.  ("ppm" means parts per million)


Annual Data | Atmospheric CO2 PDF Print E-mail

annual mean co2

Annual Atmospheric CO2 DataThe 2014 average annual concentration of CO2 in the atmosphere (Mauna Loa Observatory) is 398.55 parts per million (ppm).   The 2013 average is 396.48 ppm.  

For the past decade (2005-2014) the average annual increase is 2.1 ppm per year.  The average for the prior decade (1995-2004) is 1.9 ppm per year.    Annual data for 2014 was first posted January 6, 2015, by NOAA-ESRL in the United States. 

Since the 1958 start of high-precision instrument measurements of CO2 in the atmosphere, the annual mean concentration of CO2 has only increased from one year to the next.   The CO2 data below provide a simple view of the annual trend. 

How CO2 is Measured PDF Print E-mail


NOAA  |  In situ CO2 monitoring program

NOAA  |  Mauna Loa FAQs

NOAA  |  Location of the Mauna Loa Observatory


Carbon Impact Map PDF Print E-mail


When carbon fossil fuels are extracted from the Earth’s crust and burned for energy, the emitted carbon dioxide is not visible.  That makes it hard to see and know how the use of fossil fuel adds up to serious global impacts like sea level rise, increased famine and species extinction.  The Carbon Impact Map is a climate literacy tool from that traces the progression of carbon from its extraction and use to impacts on the planet and civilization to planetary feedbacks.   It presents an overall picture insix major steps.  The Carbon Impact Map is not an exhaustive list of the factors. 

Humanity's Carbon Extraction

Global Carbon Emissions PDF Print E-mail

Global Carbon Budget 2010

Global CO2 Budget 2014 posted data for the 2014 Global Carbon Budget on September 21, 2014.  Some key findings are set out below:

*In 2013, global CO2 emissions due to fossil fuel use (and cement production) were 36 gigatonnes (GtCO2); this is 61% higher than 1990 (the Kyoto Protocol reference year) and 2.3% higher than 2012.

*In 2014, global CO2 emissions are projected to increase by an additional 2.5% over the 2013 level.  

*CO2 emissions were dominated by China (28%), the USA (14%), the EU (10%), and India (7%)--with growth in all of these states except for a 1.8% decline in the EU (28 member states). 

*The 2013 carbon dioxide emissions (fossil fuel and cement production only) breakdown is: coal (43%), oil (33%), gas (18%), cement (5.5%) and gas flaring (0.6%).

*Emissions from land use change accounts for 8% of total CO2 emissions; the data suggests an overall decreasing trend in land use change emissions particularly since 2000.

*Key Sources:   CDIAC 2013 Global Carbon Budget

>>>>  Links to the source data, credits and high-resolution images are given below.