Talk:Atmospheric methane

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Section sizes

Section size for Atmospheric methane (11 sections)
Section name	Byte count	Section total
(Top)	8,411	8,411
Role in climate change	8,505	8,505
Sources	1,383	1,383
Measurement techniques	1,666	1,666
Global monitoring	12,174	12,174
Natural sinks or removal of atmospheric methane	8,169	14,098
Mean lifespan	3,023	3,023
Methanotrophs in soils and sediments	2,836	2,836
Removal technologies	70	70
Methane concentrations in the geologic past	9,181	9,181
References	127	127
Total	55,545	55,545

Archives

Archive 1

This page has archives. Sections older than 180 days may be automatically archived by when more than 8 sections are present.

Atmospheric lifetime of methane

About the section 'Mean lifespan': I was surprised to see the numbers given here for the atmospheric lifetime of methane and I believe they are somewhat confused, in particular 'By 2013, methane's mean lifetime in the atmosphere was estimated to be twelve years.' Source [69] is the Guardian with no scientific source given. Source [29] is a report from 2013 - not 2023, when it was accessed - that is based on scientific literature, which cites the IPCC 2007 report. The IPCC 2007 gives a perturbation time of 12 years and an atmospheric lifetime of 8.7 years.

The turnover time of a gas is its atmospheric abundance divided by the total loss rate. The perturbation time includes feedback mechanisms and thus better describes how long emissions actually remain in the atmosphere (=lifespan?). Usually, the atmospheric lifetime is given as a turnover time.

Newer studies including the IPCC 2013 report typically use the numbers by Prather et al. 2012 [doi:10.1029/2012GL051440] given with 9.1 years, e.g. source [68] (also mentioned in this section) that analyzes factors that change the atmospheric lifetime.

Unfortunately, no source is given for 'As of 2001, the mean lifespan of methane in the atmosphere was estimated at 9.6 years.'

Given that number is correct, the first paragraph is then somewhat misleading if the lifetime actually drops from 9.6 to 9.1. The variation in the estimated OH sink (difficult to quantify), probably plays a significant role.

In total, I think some work is required here to put this paragraph in line with the scientific findings. Pelicanelson (talk) 13:15, 5 January 2024 (UTC)[reply]

In their May 21, 2021 173-page "Global Methane Assessment", the UNEP and CCAP....

Could CCAP be CCAC (abbreviation for Climate & Clean Air Coalition) instead? Thanks for your kind attention. ThomasYehYeh (talk) 06:04, 3 February 2024 (UTC)[reply]

You're right, I've correct that now. EMsmile (talk) 11:14, 2 July 2024 (UTC)[reply]

Clarification is needed for quoted wordings

"The direct radiative greenhouse gas forcing effect of methane relative to 1750 has been estimated at 0.5 W/m2 (watts per meter²) in the 2007 IPCC "Climate Change Synthesis Report 2007".: 38 " What the purpose for "0.5 W/m2" here, is it an increase from 1750's level? ThomasYehYeh (talk) 06:08, 3 February 2024 (UTC)[reply]

I think it's indeed an increase relative to the 1750s level. I've changed it now accordingly. Someone please check if I got it right. But should we replace this figure with more recent data? EMsmile (talk) 11:22, 2 July 2024 (UTC)[reply]

problem

maybe I am ranting, but this page, like almost all pages on Climate Science, lacks basic numbers how many kg of Methane are in the atmosphere ? we get ppm but not this very basic number. and IMO this sloppy lazy thinking pervades climate science. — Preceding unsigned comment added by 2601:197:D00:3CA0:2D0D:D116:491B:9A6C (talk) 13:40, 27 July 2024 (UTC)[reply]