Page 16 of 16

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.

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 ... 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%)

César 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 ... 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 ... 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.


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.

Re: The Methane Thread pt. 2

Unread postPosted: Mon 29 Jul 2019, 14:57:01
by dohboi
scientists are not sure as to why recent methane emissions into the atmosphere are surging.

Earth's methane emissions are rising and we don't know why ... -know-why/

Levels of a powerful greenhouse gas jumped again last year, continuing a surge in the past few years that researchers still cannot fully explain.

Atmospheric concentrations of methane climbed by 10.77 parts per billion in 2018, the second highest annual increase in the past two decades, according to provisional data released recently by US agency NOAA.

As, indicated by the last linked article, industry is under reporting their amounts of methane by as much as a factor of 100. Maybe this has something to do with consensus climate scientists uncertainty on anthropogenic emission rates

Industrial methane emissions are 100 times higher than reported, researchers say ... igher.html

"Emissions of methane from the industrial sector have been vastly underestimated, researchers from Cornell and Environmental Defense Fund have found."

Re: The Methane Thread pt. 2

Unread postPosted: Thu 22 Aug 2019, 07:43:40
by Tanada

April 2019: 1865.8 ppb
April 2018: 1856.7 ppb

Re: The Methane Thread pt. 2

Unread postPosted: Sat 07 Sep 2019, 16:35:04
by dohboi
Thanks again to T for keeping track of both CO2 and CH4 numbers. Ultimately, it's CO2e that we need to be watching, but that can be a bit more complex to calculate.

The majority of consensus climate change authorities (such as the IPCC and US EPA) continue to use old procedures for calculating CO2-e; yet the linked article makes it clear that following the best science available C02-e is currently well above 500ppm:

Why there's more greenhouse gas in the atmosphere than you may have realised ... lised.html
Studies published in 2016 and 2018 led to the estimate of methane's warming potential being revised upwards by 15%, meaning methane is now considered to be 32 times more efficient at trapping heat in the atmosphere than CO₂, on a per-molecule basis over a 100-year time span.

Considering this new evidence, we calculate that greenhouse gas concentrations at Cape Grim crossed the 500ppm CO₂-e threshold in July 2018.

This is higher than the official estimate based on the previous formulation for calculating CO₂-e, which remains in widespread use. For instance, the US National Oceanic and Atmospheric Administration is reporting 2018 CO₂-e as 496ppm

see also (assuming non-conservatively that ECS is about 3C):

NOAA's Annual Greenhouse Gas Index

"The IPCC suggests that a constant concentration of CO2 alone at 550 ppm would lead to an average increase in Earth’s temperature of ~3°C (5.4°F). "

Re: The Methane Thread pt. 2

Unread postPosted: Tue 10 Sep 2019, 07:49:26
by Tanada

May 2019: 1862.8 ppb
May 2018: 1854.8 ppb