2021 Mauna Loa CO2 levels

[Stephan]

Outlook:
Last year next week had an average of ca. 413.0 ppm. An increase of 2.25 ± 0.25 seems likely.

The first Sunday evening of a new decade, and time to start a new thread on Mauna Loa CO₂ levels.

Week beginning on December 27, 2020:     415.09 ppm
Weekly value from 1 year ago:                   412.80 ppm
Weekly value from 10 years ago:               390.00 ppm
Last updated: January 3, 2021

The annual increase of 2.29 ppm is as expected last week and lower than the 10 y average of 2.51 ppm/a.

Last week returned to stable values. As usual for this time of the year the values increase from day to day.

Outlook:
The first week of 2020 had an average of 413.0 ppm. Therefore I expect an annual increase of 2.40 ± 0.20 ppm in the forthcoming week.

[Stephan]

Outlook:
The first week of 2020 had an average of 413.0 ppm. Therefore I expect an annual increase of 2.40 ± 0.20 ppm in the forthcoming week.

It is time for an update of Mauna Loa CO₂ weekly average.

Week beginning on January 3, 2021:     415.25 ppm
Weekly value from 1 year ago:              413.39 ppm
Weekly value from 10 years ago:           391.73 ppm
Last updated: January 10, 2021

The annual increase of 1.86 ppm is much lower than expected, partly due to my not well matching guess of last year's value (413.39 instead of 413.0 ppm). The increase is also lower than the average of the last 10 years (2.35 ppm).
Jan 05 and Jan 08 had lower values than the other days, partly due to high intra-day variability.

Outlook:
Last year next week had an average of 413.3 ppm. An increase of 2.3 ± 0.25 ppm seems to be likely.

[Stephan]

Outlook:
Last year next week had an average of 413.3 ppm. An increase of 2.3 ± 0.25 ppm seems to be likely.

Sunday evening - time for an update of Mauna Loa CO₂ levels.

Week beginning on January 10, 2021:     414.83 ppm
Weekly value from 1 year ago:               412.76 ppm
Weekly value from 10 years ago:            390.64 ppm
Last updated: January 17, 2021

The annual increase is at 2.07 ppm, higher than last week but lower than the 10 y average of 2.42 ppm/a. After some stable days at the beginnig of the week the last two days were "unavailable" with a very high intra-day variability.
An outlook seems not to be reasonable this week.

[wolfpack513]

2020’s growth rates are right in line with lagged ENSO.  A weak Niño transitioned to La Niña in 2020. However with a 4 month lag, Niña was only just starting to show by November/December: dropping CO2 growth rates. That drop will continue well into 2021.  Don’t fall for COVID as the culprit.  ENSO variability on *concentration growth rates is >>> than 4-7% drop in anthropogenic *emissions. 

[Stephan]

It is Sunday evening, and new Mauna Loa CO₂ data are available.

We have gone through the little mid January minimum and go back into another increase for the next three weeks. The stability of the values has returned in the beginning of the week, so there were no "unavailable" days. But the last two days showed a peak, combined with higher intra-day fluctuations.

Week beginning on January 17, 2021:     415.18 ppm
Weekly value from 1 year ago:               413.80 ppm
Weekly value from 10 years ago:            391.63 ppm
Last updated: January 24, 2021

The annual increase of 2.38 1.38 ppm is almost 1 ppm lower than at the 10 y average of 2.36 ppm/a.

Outlook:
Last year next week had an average of about 413.6 ppm. Assuming that the peak will fade away an increase of 2 ppm/a should be expected.

[kassy]

It must be 1,38?

[Stephan]

Oh yes. My math wasn't good last night. Got it fixed. Thanks.

[Stephan]

Outlook:
Last year next week had an average of about 413.6 ppm. Assuming that the peak will fade away an increase of 2 ppm/a should be expected.

Sunday evening, a new CO₂ weekly average has been published by NOAA.

Week beginning on January 24, 2021:     415.77 ppm
Weekly value from 1 year ago:               413.73 ppm
Weekly value from 10 years ago:            391.49 ppm
Last updated: January 31, 2021

The annual increase of 2.04 ppm is lower than the 10 y average of 2.43 ppm/a.
The anomalies of last week have been "repaired".
4.23 ppm to go for the threshold value of 420 ppm, given in the poll (see in 2020 Mauna Loa CO₂ levels thread, just some more days to vote). Last year the difference between now and the highest weekly average was ca. 3.75 ppm.

Outlook:
Next week last year had an average of ca. 414.2 ppm (a little bit hard to estimate because of high day-to-day variations). Extrapolating the actuel trend into the near future will give us an annual increase of 1.8 ppm/a.

[kassy]

Next week also includes the end date of the 420 poll attached to last years thread:
https://forum.arctic-sea-ice.net/index.php/topic,2983.0.html

Voting closes on february 4th.

[Stephan]

Thank you kassy for reminding us all. So far 36 members have given their vote, please place your bet if you haven't done so already.

[Stephan]

And this is the result of the poll.
38 members have made their choice, the majority (myself included) chose the "May 2021" bin. In the last weeks the annual increase rate of CO₂ was below the 10 y average. If I project this behaviour onto the next months, then the winner will be one of those who voted for a bin in 2022.
See attached the screenshot of this poll, which needs two clicks to become readable.

[Stephan]

Here is the official January 2021 Mauna Loa CO₂ average.

January 2021:       415.28 ppm
January 2020:       413.39 ppm
January 2010:           391.33 ppm
Last updated: February 5, 2021

The annual increase of 1.89 ppm is lower than the 10 y average (2.39 ppm/a), a trend that has already manifested in the weekly average evaluation.

I set an index of 100 for the year 1980 [338.75 ppm]. Compared to that January 2021 is at 122.6.

[Gerntocratis#1]

Looks like there is a new all-time record high daily co2 concentration at Mauna Loa.

419.12 ppm for February 4, 2021.

[Stephan]

This is a sudden spike which should be flagged as an outlier. I am sure the values will return back to those of the last week.
See the hourly and daily averages of the last month.

[grixm]

I hope it holds, that random spike in 2018 having the record on co2levels.org has been bothering me 

[Stephan]

Outlook:
Next week last year had an average of ca. 414.2 ppm (a little bit hard to estimate because of high day-to-day variations). Extrapolating the actuel trend into the near future will give us an annual increase of 1.8 ppm/a.

Sunday evening the latest weekly Mauna Loa CO₂ average has been published:

Week beginning on January 31, 2021:     417.12 ppm
Weekly value from 1 year ago:                414.50 ppm
Weekly value from 10 years ago:             392.19 ppm
Last updated: February 7, 2021

The annual increase is 2.62 ppm, which lies above the 10 y average of 2.49 ppm/a. The increase rate is much higher than expected last week. It has been caused by the spike that has been reported about upthread. It reached its maximum on Feb 05 with 419.45 ppm, on Feb 07 the value has almost reached its pre-spike level (ca. 416.3 ppm).

Outlook:
Without any further spike the annual increase should go down to around 2.0 ppm.

[wolfpack513]

2021’s January growth rate of ~1.9 ppm falls in line with lagged ENSO. Lowest value since the tail end of 2017-2018 La Niña. 

The high weekly value at Mauna Loa follows typical behavior from enhanced convection from passing kelvin wave, equatorial Rossby wave. Convection lifts higher than usual amounts of CO2 concentration above marine inversion. Suppressed convection does the opposite: enhances marine layer inversion.

[Hefaistos]

Thanks wolfpack and Stephan, that you follow this and provide some depth knowledge as well!

[Stephan]

Outlook:
Without any further spike the annual increase should go down to around 2.0 ppm.

Sunday evening means a new weekly average of Mauna Loa CO₂ levels.

Week beginning on February 7, 2021:     416.91 ppm
Weekly value from 1 year ago:               414.91 ppm
Weekly value from 10 years ago:           391.64 ppm
Last updated: February 14, 2021

The annual increase of 2.00 ppm has returned to the pre-spike level. It is now again lower than the 10 y average of 2.53 ppm/a.
But a smaller spike was visible on Feb 10, Feb 13 was "unavailable".
We are now in a period of slowly decreasing values until beginning of March, after that the CO₂ levels will increase again.
We are 3.09 ppm away from the threshold of 420 ppm of the poll. Last year the difference between this week and the maximum was 3.00 ppm. So it is not decided yet.

Outlook.
Next week last year averaged at 414.2 ppm. I expect an increase of 2.25 ± 0.25 ppm.

[Stephan]

Please note that NOAA has updated its calibration method.

Quote:
"The WMO CO₂ in air scale has been updated to WMO CO₂ X2019. This scale revision has been retroactively applied to all calibrations performed at NOAA. Full details of the WMO CO₂ X2019 scale is given in Hall et al., 2020

The WMO CO₂ X2019 scale is based on 19 primary standards covering the nominal mole fraction range 250 - 800 ppm. All primary standards are natural air in high pressure aluminum cylinders. The CO₂ content was modified by spiking with a 10% CO₂ in natural air gas to target higher than ambient values or by trapping CO₂ during a portion of the filling process to target lower than ambient values. Value assignment of the primary standards comes from repeated (approximately every 2-3 years) manometric determinations. ..."

see for more details https://www.esrl.noaa.gov/gmd/ccl/co2_scale.html

This new calibration method does not mean a change in CO₂ levels and it does not force a re-evaluation of already measured values.

[Stephan]

Outlook.
Next week last year averaged at 414.2 ppm. I expect an increase of 2.25 ± 0.25 ppm.

My Sunday evening post gives you the latest weekly Mauna Loa CO₂ average.

Week beginning on February 14, 2021:     416.51 ppm
Weekly value from 1 year ago:                 414.12 ppm
Weekly value from 10 years ago:              391.92 ppm
Last updated: February 21, 2021

The annual increase is 2.39 ppm, close to the 10 y average of 2.46 ppm/a.
The values finally have "recovered" from the peak two weeks ago.
Next week we will see the local end of Feb minimum, an increase of the values through March and April shall be expected after that.
We are 3.49 ppm away from the threshhold value of the poll. Last year the difference between this week and the maximum end of May has been ca. 3.4 ppm. So it is not decided yet.

Outlook:
Last year's next week saw an average of 414.0 ppm. An increase of 2.3 ppm ± 0.25 seems to be likely.

[interstitial]

Us emissions theoretical. I wonder how far off they will be from reality

[Stephan]

Outlook:
Last year's next week saw an average of 414.0 ppm. An increase of 2.3 ppm ± 0.25 seems to be likely.

Sunday evening, time for an update of Mauna Loa CO₂ levels.

Week beginning on February 21, 2021:     416.31 ppm
Weekly value from 1 year ago:                 413.96 ppm
Weekly value from 10 years ago:             392.32 ppm
Last updated: February 28, 2021

The annual increase of 2.35 ppm is close to the 10y average of 2.40 ppm/a.

This week was very quiet, the values were stable. We probably saw the seasonal minimum on Feb 25. A slow increase in the next week shall be expected.
We are 3.69 ppm away from the "poll value". Last year the increase from now to the annual maximum was 3.7 ppm. So it is not decided yet.

Outlook:
Last year next week averaged at 414.0 ppm. So we should expect an annual increase of 2.3 ± 0.25 ppm.

[Stephan]

Each 5th of a new month the latest monthly average of Mauna Loa CO₂ has been published by NOAA:

February 2021:       416.75 ppm
February 2020:       414.34 ppm
February 2011:          391.86 ppm
Last updated: March 5, 2021

The annual increase of 2.41 ppm is lower than the average of 2020 and lower than the average of the last ten years (2.49 ppm/a), but higher than that of the last two months.

[Stephan]

Outlook:
Last year next week averaged at 414.0 ppm. So we should expect an annual increase of 2.3 ± 0.25 ppm.

My Sunday evening post gives you the latest Mauna Loa CO₂ weekly average.

Surprise, surprise. My expectation was wrong, look for yourself:
Week beginning on February 28, 2021:     417.97 ppm
Weekly value from 1 year ago:                 414.07 ppm
Weekly value from 10 years ago:             392.12 ppm
Last updated: March 7, 2021

What has happened?
From March 1 on the daily values climbed by about 1.5-2 ppm and stayed at that elevated level for the whole week. This resulted in an annual increase of incredible 3.90 ppm.
Because this week is exceptional there is neither an evaluation of the poll value nor an outlook. Sorry.

[oren]

Wow. Hopefully it will revert to mean next week.

[wolfpack513]

As Stephan mentioned above, February 2021 came in with a growth of 2.41 ppm over February 2020. Still following lagged ENSO for the most part. The peak of the 2020-2021 La Niña still not realized yet in the CO2 concentration growth data due to the lag.

[Stephan]

Wow. Hopefully it will revert to mean next week.

Yes, it returned to normal this week. Here is the latest weekly average of Mauna Loa CO₂:

Week beginning on March 7, 2021:     416.94 ppm
Weekly value from 1 year ago:           414.34 ppm
Weekly value from 10 years ago:       392.22 ppm
Last updated: March 14, 2021

The annual increase is 2.60 ppm, above the 10 y average of 2.47 ppm/a.
As I wrote above, the values have returned to normal level with an acceptable small intra-day variability.
3.06 ppm difference to the "poll value" of 420 ppm. Last year the difference from this week to the maximum was 3.3 ppm. But this week we have to take into account that two days still belonged to the peak from last week. "Purified" from this, the weekly average would have been at 416.5 ppm, the distance being then 3.5 ppm. Too early to say whether we will meet the poll value of 420 ppm in May 2021.

Outlook for next week:
Last year the average was at 414.5 ppm. Assuming a slight increase from this week's values I expect an annual increase around 2.3 ppm.

[Stephan]

Outlook for next week:
Last year the average was at 414.5 ppm. Assuming a slight increase from this week's values I expect an annual increase around 2.3 ppm.

My sunday evening post on Mauna Loa CO₂ levels is ready.

Week beginning on March 14, 2021:     417.73 ppm
Weekly value from 1 year ago:             414.52 ppm
Weekly value from 10 years ago:          392.63 ppm
Last updated: March 21, 2021

The annual increase of 32.21 ppm is in the expected range.
It is belowwell above the 10 y average of 2.51 ppm/a.
At this time of the year we are in the fast increasing part of the Keeling curve. Most days (except yesterday) showed acceptably or good daily stability.
We are 2.27 ppm away from the 420 ppm poll value. Last year the increase from this week to the maximum was 3 ppm. So it might be possible that 420 ppm can be reached, but last year next week showed a jump of almost 1.5 ppm which must be taken into account. Therefore it should be wise to wait until next Sunday to be sure, whether a weekly average of above 420 ppm can be reached this May.

Outlook:
Last year the next week had an average of 415.8 ppm. The annual increase will be around 2.5 ppm and probably follow the same 'jump' NOAA has observed one year ago.

[Gerntocratis#1]

The annual increase is actually 3.21 not 2.21

[Stephan]

Thank you. Got it corrected. I should visit a basic math course...

[oren]

Thank you Stephan for these recurring updates.

[Stephan]

Outlook:
Last year the next week had an average of 415.8 ppm. The annual increase will be around 2.5 ppm and probably follow the same 'jump' NOAA has observed one year ago.

It is Sunday evening and here are the latest Mauna Loa CO₂ weekly averages:

Week beginning on March 21, 2021:     417.67 ppm
Weekly value from 1 year ago:             415.67 ppm
Weekly value from 10 years ago:          393.61 ppm
Last updated: March 28, 2021

Annual increase is 2.00 ppm.
This week saw very uneven values, the difference between the highest and the lowest daily average was almost 2.7 ppm! In addition some days were "unavailable", therefore this average does not mean too much.

No outlook and no "poll value evaluation" possible, sorry once again.
 

[kassy]

Guess we just have to wait for the poll which is good for added suspense.

At least the calculation was easy. 

[Sigmetnow]

When your target audience doesn’t appreciate math :

Eric Holthaus on Twitter: "We've officially crossed over to 418ppm, the highest atmospheric carbon dioxide levels in millions of years — before the pyramids, before the ice age, before modern humans existed. Humanity has never experienced our planet like this. We are in a climate emergency.”
https://twitter.com/EricHolthaus/status/1377518011586912258

[crandles]

When your target audience doesn’t appreciate math :

Eric Holthaus on Twitter: "We've officially crossed over to 418ppm, the highest atmospheric carbon dioxide levels in millions of years — before the pyramids, before the ice age, before modern humans existed. Humanity has never experienced our planet like this. We are in a climate emergency.”
https://twitter.com/EricHolthaus/status/1377518011586912258

Last global monthly number
December 2020:       414.49 ppm
Last Mauna loa monthly number
Last Mauna loa annual number
2020:   414.24
Last Mauna loa monthly number
February 2021:       416.75 ppm
Last Mauna loa weekly number
Week beginning on March 21, 2021:     417.72 ppm
Last Mauna loa daily number
March 31:     417.41 ppm

so what does "officially crossed over to 418ppm" mean 

[Stephan]

This is what is meant by "CO₂ has risen over 418 ppm at Mauna Loa":
11-12 days (depending how you draw the green line) since March 2, 2021 showed daily averages above 418 ppm.
See attached screenshot from NOAA.

[interstitial]

looking at the chart one of the daily averages is around 419 ppm and one of the hourly averages is 422 ppm.
My guess is "officially crossed over" means the "monthly average is over" but I am guessing.
Another thought I wonder if decarbonizing the Hawaii electric grid and replacing fossil fuel vehicles with electric will significantly reduce the Mona Loa CO2 numbers variations.

[Tor Bejnar]

Mauna Loa was selected back in 1958, I understand, because the 4,170 m (13,680 ft) peak's air is dominated by pretty well mixed air flowing over half the Pacific.  Hawaii's (the Big Island's) volcanoes spew lots of gas, including CO2; when the daily readings are contaminated by this local source, they are purged.  Auto emissions in Honolulu, Oahu, 300 km (200 mi) away, or the towns which are all near Hawaii's (the Big Island's) coasts, will 'never' affect Mauna Loa readings.

[Diaminedave]

Hi Mr Crandles
Sigificant Figures rounds up to
Nothing more han that ...plus a little bit of stirring I suspect

[interstitial]

Mauna Loa was selected back in 1958, I understand, because the 4,170 m (13,680 ft) peak's air is dominated by pretty well mixed air flowing over half the Pacific.  Hawaii's (the Big Island's) volcanoes spew lots of gas, including CO2; when the daily readings are contaminated by this local source, they are purged.  Auto emissions in Honolulu, Oahu, 300 km (200 mi) away, or the towns which are all near Hawaii's (the Big Island's) coasts, will 'never' affect Mauna Loa readings.

I assumed Hawaii was selected for its remoteness from man made sources of co2. I have no reason to fault their site selection. I just wondered because some days measurements are all over the place and others are more stable. I assume that most of the time these instabilities have more to do with atmospheric conditions than instrument problems. If humanity stopped emitting co2 would the variability shrink or is it just the nature of atmospheric mixing? I was just curious.

[Tor Bejnar]

I have a vague memory of having read that the "pretty well mixed air" that mixes without much human involvement over the western Pacific is less well mixed than scientists had presumed 60 years ago.  This doesn't mean Mouna Loa isn't an excellent location to take Northern Hemisphere readings.

From Skeptical Science:

The influence of the volcano is easily spotted and removed, together with other even more important spurious influences.
...
A more subtle effect [than volcanic CO2 emissions contaminating the trans-Pacific air] is due to the diurnal cycle of the winds along the slopes of the mountain. After sunrise, the rising air from the warming land causes the winds to go uphill. Due to the diurnal photosynthesis cycle, this air is impoverished of CO2. After sunset this process reverses and the winds going downhill bring "clean" air from higher altidudes.

CO2 concentration measurements are taken continuously but are analyzed on a hourly basis.  ...

Much more, of course, at skepticalscience.

[interstitial]

interesting Tor thanks

[Stephan]

Sunday evening - the latest weekly average of Mauna Loa CO₂ is available.

Week beginning on March 28, 2021:     418.03 ppm
Weekly value from 1 year ago:             415.95 ppm
Weekly value from 10 years ago:         393.88 ppm
Last updated: April 4, 2021

The annual increase of 2.08 is lower than the 10 y average of 2.42 ppm/a and for the first time in human history above 418 ppm (see the short discussion upthread).

The "poll value" is now 1.97 ppm away. Last year the distance between this week and the maximum week was around 1.8 ppm. But it has to be taken into account that on April 03, 2021 the value peaked at 421.21 ppm which has lifted the weekly average by about 0.4 ppm. Therefore nothing is decided yet...

Outlook:
Last year next week had an average of 416.6 ppm. The annual increase should therefore decrease to around 1.4 ppm, assuming the peak of April 03 disappears and the values return to normal.

[Sebastian Jones]

Yes, it's an outlier, but for the 1st time a daily average reading over 421ppm:
https://www.esrl.noaa.gov/gmd/ccgg/trends/monthly.html

[karl dubhe2]

Yes, it's an outlier, but for the 1st time a daily average reading over 421ppm:
https://www.esrl.noaa.gov/gmd/ccgg/trends/monthly.html

How totally rude.   Somehow, this event should have waited for 4/20.     

[Stephan]

Here is the official monthly average of CO₂ for March 2021:

March 2021:       417.64 ppm
March 2020:       414.74 ppm
March 2011:       392.60 ppm
Last updated: April 7, 2021

The annual increase of 2.90 ppm is - due to several "peaks" and "outliers" - above of the increase rates of the last months and above the 10y average increase rate of 2.50 ppm/a. March 2021 lies 0.42 ppm above the long term linear trend line.
With an index 1980 = 100.0 the CO₂ concentration in March 2021 has grown to 123.3

The increase rate is further slowly increasing, see the orange trend line in the attached graph.

[Stephan]

!! Please note that March 2021 had the highest monthly average in human history (May 2020 was at 417.07 ppm) !!

[Ktb]

US Carbon Monitor launched today.

Shows CO₂ emissions from the US as a whole and each individual state, and from each sector of the economy.

Currently the website compares Jan 1st-Feb 28th 2021 to the same period from 2020.

https://us.carbonmonitor.org/

[Stephan]

Outlook:
Last year next week had an average of 416.6 ppm. The annual increase should therefore decrease to around 1.4 ppm, assuming the peak of April 03 disappears and the values return to normal.

Because there was a second spike this week, my prediction did not come true at all. But it was not only for the spike, also the baseline showed a steep increase.

Week beginning on April 4, 2021:     419.28 ppm
Weekly value from 1 year ago:         416.64 ppm
Weekly value from 10 years ago:     393.00 ppm
Last updated: April 11, 2021

The annual increase is at 2.64 ppm, almost close to the 10 y average of 2.63 ppm/a.
The highest weekly average since humans live on this planet

The difference to the poll value is 0.72 ppm. Last year the difference between this week and the maximum end of May was around 0.9 ppm. Therefore it is still not decided, whether we will reach a weekly average of > 420 ppm in May 2021. Maybe another "spike event" will help to reach it.

Outlook:
Last year next week averaged at 416.5 ppm. With the latest, higher, baseline an annual increase of about 2.75 ppm seems to be possible.