CO2 measurements are made by two independent CO2 monitoring programs (NOAA and Scripps) at the Mauna Loa Observatory in Hawaii, about 3400 metres above sea level. Explore the tabs below where you will see daily CO2 charts and related links.

NOTE: The Daily CO2 page is now a beta web app. We are making adjustments as needed to ensure that daily CO2 readings are kept up-to-date and accurate. This work is self-funded and brought to you by a small number of volunteers who are promoting widespread sharing and reporting of CO2 levels to spur conversations and innovations that ramp up efforts to stabilize GHGs in the atmospher end end the global climate crisis.

Resource hub for broadcasters, publishers, bloggers and others who are share the CO2 signal with people in their worlds.

Resource hub for broadcasters, publishers, bloggers and others who are share the CO2 signal with people in their worlds.

Questions and answers on all thing CO2: From measurements and tracking to targets and solutions.

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This table presents the most up-to-date, daily average reading for atmospheric CO2 on the planet. Units = parts per million (ppm). Measurement location = Mauna Loa Observatory, Hawaii. Source = NOAA-ESRL . See the tabs below for more info and CO2 readings.

Daily Global CO 2 Trend

NOAA's Daily Global CO2 chart averages seasonally-adjusted data from four core observatories at different latitudes from the South Pole to Alaska. Recent values are estimates, not current observations.

Source Graphic: NOAA Global CO2 Trend webpage

NOAA states that lines in the graphic "are a very good estimate of the global average levels of CO2."

NOAA | Estimated CO2 Trend (seasonally adjusted) daily values

NOAA | Curve Fitting Methods Applied to Time Series in NOAA/ESRL/GMD

Why does the graph show us?

NOAA's Daily Global CO2 table shows us atmospheric CO2 phenomena that Charles David Keeling discovered with the high-precesion CO2 measuring instruments and programs he created in the 1950s. These phenomna include:

seasonal fluctuations of CO2 levels in well-mixed background air that is free of local influence such as plant respiration and industry

large difference in seasonable fluctuations betwen the South Pole (least fluctuation) to near the North Pole (highest fluctuation) which shows that seasonal fluctuations are driven mainly by vegetation cycles in the Northern Hemisphere where most land is located.

year-over-year increases in carbon dioxide--increases that have continued and accelerated since Keeling's discovery and which scientists attribute primarily to emissions caused by human activities (roughly 90% fossil fuel combustion and most of the remainder due to land use changes)

Why does CO2 Earth focus on Mauna Loa CO2 readings?

Maybe you are wondering why CO2 Earth features daily readings from the Mauna Loa Observatory (MLO) alone and not a seasonally adjusted estimate? If you are, there are many reasons.

First, CO2 readings from Mauna Loa are direct observations of the Earth system. They are precise measurements of the air made at one location in the Earth's atmosphere. They are not projections, estimates or averages that use advanced mathematics to generate a daily number. CO2 Earth was created to make it easy for non-scientists to see changes of consequence to the planet as they happen. Whether the CO2 problem is getting worse or getting resolved, people deserve to have access to objective informaiton without filters and delays. For this reason, CO2 Earth use data from direct observations when it reports the latest available CO2 levels.

This brings us to another reason. Unlike CO2 readings from other observing stations in the world, CO2 readings from Mauna Loa are practically real time.

A third reason relates to reliability. CO2 readings are available from not one, but two scientific institutions: NOAA ESRL (Global Monitoring Division) and the Scripps Institution of Oceanography at UCSD (Scripps CO2 Program). Each institution measures CO2 readings with separate instruments and reports their readings indepndently of the other. Scripps started continuous measurements at Mauna Loa in 1958. The NOAA-ESRL program started in 1974.

Fourth, the Mauna Loa CO2 record is the the world's longest, continuous record of observations using high precision instruments. Observations today can be compared against observations at the same location over a period of time that is longer than any other.

Fifth, year-over-year comparisons of Mauna Loa CO2 gives people a signal of planetary significance. It's true that Mauna Loa is just a spot on the map. But the year-over-year trend in the Mauna Loa CO2 is essentially the same as the trends at other observing stations. “CO2 is rising everywhere, and at about the same rate” (Volk, 2008, pp. 39-41). Further, the CO2 data presents a trend that is so clear that statistical analysis is not needed to detect it (Tans & Bolin, 2006, p. 329).

And then there is the Mauna Loa Observatory and its remote location in the middle of the largest and deepest ocean on the planet. It is 3,400 metres above sea level on a slope about 3/4 of a kilometre metres below the top of the tallest mountain on Earth. (McGee, 2017, p. 99) NOAA-ESRL states that "the undisturbed air, remote location, and minimal influences of vegetation and human activity at MLO are ideal for monitoring constituents in the atmosphere that can cause climate change (NOAA-ESRL, GMD, 2020)."