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Re: The Methane Thread pt. 2

Unread postPosted: Wed 19 Jun 2019, 13:54:15
by Tanada
Before anyone gets too wound up over current methane levels remember to look at this graph. Since high quality monitoring started we have gone from roughly 1.63 ppmv CH4 free in the atmosphere to 1.86 ppmv. Even if you take the worst case scenario with CH4 having 125*CO2 global warming potential that increase of 0.23 ppmv only adds up to 28.75 ppmv CO2 equivalent increase. During the same period actual CO2 levels increased from 338.1 ppmv in January 1980 to 410.83 ppmv CO2 in January 2019. That is a real world increase of 72.73 ppmv CO2 or more that three times the CH4 increase worst case scenario impact. While CH4 emissions continue to grow they are tiny in comparison to the main culprit in man influencing the climate. Also remember that about half of the actual change induced by CO2 is in the continuing increase in atmospheric humidity because warm air holds more water vapor and water vapor is the most powerful GHG. When the CH4 reaches the Ozone Layer it gets converted into CO2+2(H2O) if it doesn't get broken down by OH- radicals before it rises that high. So CH4 is a self limiting problem, as long as the sun keeps emitting so much UV radiation the Ozone layer gets constantly rebuilt. H2O on the other hand tends to saturate dust motes into micro droplets, then keep growing until the droplets are heavy enough to actually precipitate out of the atmosphere. Unlike those two however the CO2 in the upper atmosphere tends to remain in the upper atmosphere for geological timescales of thousands to hundreds of thousands of years.
Image
https://www.esrl.noaa.gov/gmd/ccgg/trends_ch4/

Re: The Methane Thread pt. 2

Unread postPosted: Wed 03 Jul 2019, 16:26:26
by dohboi
Thanks for the perspective, T. Still, I would say the most important phrase in your explanation is 'so far.'

The following study is about both methane and CO2, but such issues seem to usually go in this thread, so here it is (thanks to vox at asif...does he come here anymore?):

Scientists Find Thawing Permafrost Releasing Carbon at Higher Rates than Previously Thought


https://phys.org/news/2019-07-scientist ... igher.html

... "This study was novel because we used new methods to directly track the soil carbon losses, and they were much higher than we previously thought," Schuur said. "This suggests that not only is carbon being lost through greenhouse gases directly to the atmosphere but also dissolved in waters that flow through the soil and likely carried carbon into streams, leaves and rivers."

... According to the study, 5 to 15 percent of the soil carbon held in the permafrost could be released into the atmosphere by the end of the century, using the original scenario. The modeling exercise the research team used to compare agreed with the observations but suggests that the loss rate could be twofold or more higher. (I.e. >10-30%)

C├ęsar Plaza et al. Direct observation of permafrost degradation and rapid soil carbon loss in tundra, Nature Geoscience (2019)

Re: The Methane Thread pt. 2

Unread postPosted: Wed 10 Jul 2019, 10:35:32
by dohboi
New (to me) link to methane mapping site:


Methane forecasts

https://atmosphere.copernicus.eu/charts ... h4_surface

Re: The Methane Thread pt. 2

Unread postPosted: Wed 10 Jul 2019, 15:01:15
by Plantagenet
dohboi wrote:New (to me) link to methane mapping site:


Methane forecasts

https://atmosphere.copernicus.eu/charts ... h4_surface


WOW! Thats really interesting. My eye immediately went to the three CH4 hot spots in Arctic Alaska. What in heck is that......

But then I saw the much bigger Methane hot spot over Sweden and Scandinavia. And finally the gigantic CH4 anomalies over Siberia and China.

And all I can saw is : We are screwed. We are truly screwed.

Cheers!

Re: The Methane Thread pt. 2

Unread postPosted: Wed 10 Jul 2019, 17:59:28
by dohboi
Yeah, the folks that said that the thawing tundra is a more immediate threat than the subsea clathrates seem to have been right, I am ready to concede. Clathrates are still the sleeping/slowly-awaking giant, though, imho.