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Author Topic: Trends in atmospheric CH4  (Read 8757 times)

Shared Humanity

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Re: Trends in atmospheric CH4
« Reply #50 on: February 09, 2020, 07:37:43 PM »
I second Oren with the thanks. Tracking these atmospheric levels of greenhouse gases is the single best way to measure the adequacy of our efforts to avoid catastrophic warming. You are doing this site a service by providing these updates which serve as a context for discussions on many threads on this site. The numbers are not good but necessary.

Stephan

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Re: Trends in atmospheric CH4
« Reply #51 on: February 09, 2020, 09:00:58 PM »
Thank you SH.
I try to be as early and as reliable (concerning the time I find to do the posting and to compare the actual data with older ones and compute slopes) as possible. Just a number (x,yyy.z ppb) is in my opinion not enough to feed a discussion.
It is too late just to be concerned about Climate Change

dnem

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Re: Trends in atmospheric CH4
« Reply #52 on: February 19, 2020, 09:54:31 PM »
https://www.nature.com/articles/s41586-020-1991-8

Preindustrial 14CH4 indicates greater anthropogenic fossil CH4 emissions

Abstract
Atmospheric methane (CH4) is a potent greenhouse gas, and its mole fraction has more than doubled since the preindustrial era1. Fossil fuel extraction and use are among the largest anthropogenic sources of CH4 emissions, but the precise magnitude of these contributions is a subject of debate2,3. Carbon-14 in CH4 (14CH4) can be used to distinguish between fossil (14C-free) CH4 emissions and contemporaneous biogenic sources; however, poorly constrained direct 14CH4 emissions from nuclear reactors have complicated this approach since the middle of the 20th century4,5. Moreover, the partitioning of total fossil CH4 emissions (presently 172 to 195 teragrams CH4 per year)2,3 between anthropogenic and natural geological sources (such as seeps and mud volcanoes) is under debate; emission inventories suggest that the latter account for about 40 to 60 teragrams CH4 per year6,7. Geological emissions were less than 15.4 teragrams CH4 per year at the end of the Pleistocene, about 11,600 years ago8, but that period is an imperfect analogue for present-day emissions owing to the large terrestrial ice sheet cover, lower sea level and extensive permafrost. Here we use preindustrial-era ice core 14CH4 measurements to show that natural geological CH4 emissions to the atmosphere were about 1.6 teragrams CH4 per year, with a maximum of 5.4 teragrams CH4 per year (95 per cent confidence limit)—an order of magnitude lower than the currently used estimates. This result indicates that anthropogenic fossil CH4 emissions are underestimated by about 38 to 58 teragrams CH4 per year, or about 25 to 40 per cent of recent estimates. Our record highlights the human impact on the atmosphere and climate, provides a firm target for inventories of the global CH4 budget, and will help to inform strategies for targeted emission reductions9,10.


Stephan

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Re: Trends in atmospheric CH4
« Reply #53 on: March 06, 2020, 08:41:18 PM »
Finally, also CH4 received an update by NOAA:

November 2019:     1877.0 ppb
November 2018:     1866.2 ppb
Last updated: March 05, 2020

This converts into CO2 eq: 57.3 / 19.1 ppm (20 y / 100 y)

The annual increase of 10.8 ppb is at the very upper end of what has been observed in the last years. You have to go back to 2015/16 to find comparable rates.

I set an index of 100 to Jan 2000. November 2019 has a relative value of 105.7.
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Stephan

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Re: Trends in atmospheric CH4
« Reply #54 on: April 06, 2020, 09:00:30 PM »
Finally, also CH4 received an update by NOAA:

December 2019:     1874.7 ppb
December 2018:     1866.0 ppb
Last updated: April 05, 2020

The 2019 average is thus 1866.9 ppb, 9.5 ppb above the 2018 average.

This converts into CO2 eq: 57.3 / 19.1 ppm (20 y / 100 y)

The annual increase of 8.7 ppb is in the upper half of what has been observed in the last years, but much lower than in July-November 2019 (see posts above in this thread).

I set an index of 100 to Jan 2000. December 2019 has a relative value of 105.6.
It is too late just to be concerned about Climate Change

Stephan

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Re: Trends in atmospheric CH4
« Reply #55 on: May 05, 2020, 10:26:28 PM »
It is the fifth of the new month and so the average values of the "NOAA gases" are available.
Here is the value of CH4:

January 2020:     1873.5 ppb
January 2019:     1865.0 ppb
Last updated: May 05, 2020

This converts into CO2 eq: 57.2 / 19.1 ppm (20 y / 100 y)

The annual increase of 8.5 ppb is in the upper half of what has been observed in the last years, but much lower than in July-November 2019 (see posts above in this thread).

I set an index of 100 to Jan 2000. January 2020 has a relative value of 105.5.
It is too late just to be concerned about Climate Change

Stephan

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Re: Trends in atmospheric CH4
« Reply #56 on: June 05, 2020, 09:25:14 PM »
It is the fifth of the new month. Therefore the monthly averages of the "NOAA gases" are available. Here is the value of CH4:

February 2020:     1873.7 ppb
February 2019:     1864.9 ppb
Last updated: June 05, 2020

This is an annual increase of 8.8 ppb. This increase is still in the upper half of what has been observed in the last years.

I set an index = 100 for the 1980 average [1601.2 ppb]. February 2020 is at 117.0 compared to that index.
It is too late just to be concerned about Climate Change

Stephan

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Re: Trends in atmospheric CH4
« Reply #57 on: July 06, 2020, 09:13:58 PM »
It is the fifth of the new month. Therefore the monthly averages of the "NOAA gases" are available. Here is the value of CH4:

March 2020:     1876.4 ppb
March 2019:     1866.3 ppb
Last updated: July 05, 2020

This is an annual increase of 10.1 ppb. This increase is in the upper half of what has been observed in the last years.

I set an index = 100 for the 1980 average [1601.2 ppb]. March 2020 is at 117.2 compared to that index.
It is too late just to be concerned about Climate Change

Stephan

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Re: Trends in atmospheric CH4
« Reply #58 on: August 06, 2020, 07:36:11 PM »
It is the fifth of the new month. Therefore the monthly averages of the "NOAA gases" are available. Here is the value of CH4:

April 2020:     1876.3 ppb
April 2019:     1865.3 ppb
Last updated: August 05, 2020

This is an annual increase of 11.0 ppb. This increase is in the upper half of what has been observed in the last years.

I set an index = 100 for the 1980 average [1601.2 ppb]. April 2020 is at 117.2 compared to that index.

Attached the development since 1980. A much more complicated pattern than the CO2, N2O or SF6 graphs.
It is too late just to be concerned about Climate Change

Stephan

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Re: Trends in atmospheric CH4
« Reply #59 on: September 10, 2020, 08:32:31 PM »
Here is the latest monthly average of Mauna Loa CH4 concntration:

May 2020:     1874.7 ppb
May 2019:     1861.9 ppb
Last updated: September 05, 2020

This is an annual increase of 12.8 ppb. This is the highest annual increase since March 2015!

I set an index = 100 for the 1980 average [1601.2 ppb]. May 2020 is at 117.1 compared to that index.

It is too late just to be concerned about Climate Change

Stephan

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Re: Trends in atmospheric CH4
« Reply #60 on: October 06, 2020, 08:35:52 PM »
Here is the latest monthly average of Mauna Loa CH4 concentration:

June 2020:     1872.2 ppb
June 2019:     1858.8 ppb
Last updated: October 05, 2020

This is an annual increase of 13.4 ppb. This is the highest annual increase since February 2015!

I set an index = 100 for the 1980 average [1601.2 ppb]. June 2020 is at 116.9 compared to that index.
It is too late just to be concerned about Climate Change