From: DOE/LAWRENCE BERKELEY NATIONAL LABORATORY
First direct observations of methane’s increasing greenhouse effect at the Earth’s surface
Scientists have directly measured the increasing greenhouse effect of methane at the Earth’s surface for the first time. A research team from the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) tracked a rise in the warming effect of methane – one of the most important greenhouse gases for the Earth’s atmosphere – over a 10-year period at a DOE field observation site in northern Oklahoma.
These findings were published online April 2 in the journal Nature Geoscience in an article entitled “Observationally derived rise in methane surface forcing mediated by water vapour trends.” The paper indicates that the greenhouse effect from methane tracked the global pause in methane concentrations in the early 2000s and began to rise at the same time that the concentrations began to rise in 2007.
“We have long suspected from laboratory measurements, theory, and models that methane is an important greenhouse gas,” said Berkeley Lab Research Scientist Dan Feldman, the study’s lead author. “Our work directly measures how increasing concentrations of methane are leading to an increasing greenhouse effect in the Earth’s atmosphere.”
Gases that trap heat in the atmosphere are called greenhouse gases, in large part because they absorb certain wavelengths of energy emitted by the Earth. As their atmospheric concentrations change, the scientific community expects the amount of energy absorbed by these gases to change accordingly, but prior to this study, that expectation for methane had not been confirmed outside of the laboratory.
The scientists analyzed highly calibrated long-term measurements to isolate the changing greenhouse effect of methane. They did this by looking at measurements over the wavelengths at which methane is known to exert its greenhouse effect and coupled those with a suite of other atmospheric measurements to control for other confounding factors, including water vapor.
This study was enabled by the comprehensive measurements of the Earth’s atmosphere that the DOE has routinely collected for decades at its Atmospheric Radiation Measurement (ARM) facilities, and conversely, would not be possible without such detailed observations.
The DOE ARM program manages and supports three long-term atmospheric observatories – the Southern Great Plains observatory in Oklahoma, the North Slope of Alaska observatory in far-northern Alaska, and the Eastern North Atlantic observatory on the Azores Islands. The program also deploys three ARM mobile facilities and several ARM aerial facilities. Together, these assets enable scientists to perform highly-detailed, targeted investigations to advance the fundamental scientific understanding of the Earth system.
The researchers believe this type of direct field observation can provide a more accurate and complete picture of the relationship between atmospheric greenhouse gas concentrations and their warming effect on Earth’s surface.
The research was funded by the Department of Energy’s Office of Science.
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Here is the paper, unfortunately, even though it is funded by tax dollars, it is paywalled, which I consider an abuse of the public trust.
https://www.nature.com/articles/s41561-018-0085-9
Observationally derived rise in methane surface forcing mediated by water vapour trends
Abstract
Atmospheric methane (CH4) mixing ratios exhibited a plateau between 1995 and 2006 and have subsequently been increasing. While there are a number of competing explanations for the temporal evolution of this greenhouse gas, these prominent features in the temporal trajectory of atmospheric CH4 are expected to perturb the surface energy balance through radiative forcing, largely due to the infrared radiative absorption features of CH4. However, to date this has been determined strictly through radiative transfer calculations. Here, we present a quantified observation of the time series of clear-sky radiative forcing by CH4 at the surface from 2002 to 2012 at a single site derived from spectroscopic measurements along with line-by-line calculations using ancillary data. There was no significant trend in CH4 forcing between 2002 and 2006, but since then, the trend in forcing was 0.026 ± 0.006 (99.7% CI) W m2 yr−1. The seasonal-cycle amplitude and secular trends in observed forcing are influenced by a corresponding seasonal cycle and trend in atmospheric CH4. However, we find that we must account for the overlapping absorption effects of atmospheric water vapour (H2O) and CH4 to explain the observations fully. Thus, the determination of CH4 radiative forcing requires accurate observations of both the spatiotemporal distribution of CH4 and the vertically resolved trends in H2O.
Since the paper is pay-walled, I can’t check the veracity of the claims. but just reading over the press release, and looking at the photo and graph, I can make these observations.
- It’s one point on the globe, one measurement site. All they are doing is saying “this site, using a different measurement method, matches data gathered elsewhere”. Is that significant? Probably not.
- They mention two other ARM sites, but don’t provide data for the other two. Why?
- The photo provided looks like pasture land. How do they know what they’ve measured is representative of global trend, and not a local trend due to land use change, or increase in the number of cows?
- There’s a lot of oil and gas wells in Oklahoma, and fracking has been on the rise, perhaps that accounts for some of the increase in CH4.
- They don’t mention that methane has a short residence time in the atmosphere. The atmospheric residence time of methane is approximately 8 years . They leave the reader to think is is a permanent increase.
- The forcing went down slightly from 2002 to 2007 and then rose from 2007 to 2012. Nobody seems to be able to explain why it went down from 2002 to 2007.
- The study ends in 2012 – with just 10 years of data. Why? They don’t make that clear. Did the data start going down? Did the data source disappear?
- The graph below offers a reason for the increase from 2007 to 2012. It has data to 2015, and projections beyond.
From my viewpoint, the study raises more questions than it answers. However, based on the EIA graph above, we’ll probably hear a lot of caterwauling about methane and greenhouse effects in the future.
UPDATE: Reader Lance Wallace has made the paper and the supplemental data available
Full paper here. Also the Supporting Info with data sources
https://www.dropbox.com/s/d1o8x815an3nbqt/Feldman%202018%20methane.pdf?dl=0
https://www.dropbox.com/s/res02btd1udhfv6/Feldman%202018%20methane%20SI.pdf?dl=0
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None of these radiative models is worth a damn. It’s a stable, convective, atmosphere.
Please do not do that here.
Is the atmosphere convective? Yes, proven by thunderstorms. Means parameterized models have obviousmproblems. Is it stable? Depends on the definition of stable—MWP and LIA say not so much on centennial time frames. Is CO2 a greenhouse gas? Yes, proven by in the lab by Tyndall in 1859. How much does it matter? Dunno. As evidenced by my many past comments and guest posts here, I suspect not much. My current best estimates of ECS are 1.45-1.5. Game over.
Way too high.
thanks for the baseless assertions Pocha. That’s always a great help in assessing your level of understanding and competence.
Not baseless, Greg. Atmospheric thermodynamics is mostly ignored by the experts.
https://en.wikipedia.org/wiki/Atmospheric_thermodynamics
If it exceeds 1%, I am filing a shareholder lawsuit.
If you’re talking about sensitivity for a doubling, that’s a psychological barrier. Anyone that tries to go lower hits a stone wall and forces about a gazillion people to find something productive to do.
“Our work directly measures how increasing concentrations of methane are leading to an increasing greenhouse effect in the Earth’s atmosphere.”
I see a plot of increasing methane concentrations, but where is the plot of increasing temperatures showing a corresponding increase in the greenhouse effect? I don’t see it. And how do they determine how much is being caused by an increase in methane and how much is being caused by an increase in CO2 over the same period?
“However, to date this has been determined strictly through radiative transfer calculations. Here, we present a quantified observation of the time series of clear-sky radiative forcing by CH4 at the surface from 2002 to 2012 at a single site derived from spectroscopic measurements along with line-by-line calculations using ancillary data. ”
None of your questions are relevant to the claim being made or tested.
The Forcing of methane TO DATE has been estimated through Models, specifically LBL models of radiative transfer. These, by the way, are the same types of models we used in designing sensors and weapons that rely on stealth. Why? because to design the machine properly you need to take into account the PHYSICS OF RADIATIVE TRANSFER. This is the physics that even Willis does not deny. principly because its physics used in everyday engineering. This is the same physcis models used in weather forecasting models that you rely on. Its the physics that sky dragons deny and that many skeptics question ( stupidly)
In this study they do EXACTLY what skeptics have been asking for.. See if the theory and observations match.
Yup. But we already knew they would because the physics ACTUALLY WORKS. engineers use it, and meterrologists rely on the data produced by this physics even when dont know it.
No they didn’t Steve.
I suppose it’s confounding when water vapor cancels out the effect they want to hype, but positive feedback leading to catastrophe when they can hide that darn confounding nature, right?
“Gases that trap heat in the atmosphere are called greenhouse gases…”
Stopped reading right there.
What name do you use?
Meanwhile, an amusing bit of irony from a well known alarmist, Bob Henson, on his wunderground.com blog. (my bold)
Nice to know that even greenhouse gasses will take a spring break and allow “ample radiation.” Pondering all this as I sit here looking at the 4 inches of fresh snow outside and humming that old American favorite tune, “I’m dreaming of a white Easter.”
Maybe so but it can’t be blamed on humans
https://ssrn.com/abstract=2674147
I may be mistaken but I assume when they talk of measuring the radiative forcing of methane they are actually referring to the spectrally identified methane portion of downward longwave radiation falling on north central Oklahoma. Their graph shows a seemingly dramatic increase from THREE THOUSANDTHS W/m2 to slightly less than THREE HUNDRETHS W/m2 . The ARM data for total DLR at the OK facility is, even in the dead of winter, seldom less than THREE HUNDRED W/m2 and for most of the year is well above FOUR HUNDRED W/m2 with the difference being mostly attributable to the difference between the dryness of cold winter air and the humidity of warmer seasonal air. The methane signal would have to increase 33X to get to ONE W/m2, which change would still be swamped by the seasonal variations caused by changes in water vapor.
(Mods) Can you please delete the above comment for me?
It’s nice to see the effects of methane seriously measured and enumerated for the first time, rather than being
wildly speculated about and used to frighten the children.
Now we know for sure that it is trivial, and has risen by a trivial amount – about a sixth of a watt/m2 in 10 years, we can perhaps look forward to a more level-headed approach to its relative importance in the scheme of things.
No? You’re right, of course we can’t. All of those annoying bed-wetters who shudder with dread every time a cow farts will no doubt continue to spout their pathetic groupthink propaganda, such as “methane is a greenhouse gas that is 30 times more powerful than CO2”, a nasty little piece of deliberately misleading prevarication from the IPCC and its concept of GWP (Global Warming Potential).
Those who promote this kind of exaggeration – for the sake of scaremongering amongst the
common folk who weren’t listening during science lessons – should be ashamed of themselves.
Speaking of which, I see Stephen Mosher has weighed in again with his oft-repeated old chestnut, you know, the one about greenhouse gases elevating the effective radiating height for the final emission of IR into space, so that the gases are emitting at a cooler temperature and therefore dumping less heat. This is, I gather, when you boil it all down, the fundamental basis for thinking that the planet must be heating up.
That would seem to be a not-entirely-satisfactory explanation, as radiometric readings from space show that most of the emissions from CO2 for example come from the stratosphere, which does not have reducing temperature with altitude, or from the tropopause which is similar.
But I thank him for drawing our attention to the fact, not widely appreciated, that it is in fact the greenhouse gases at high altitude (not including water, which has effectively frozen out) that perform the vital task of dumping heat to space and thus preserving planetary thermal equilibrium. Without them, our planet would be much warmer.
This being the case, I would like to pose the following question, which I have never seen raised or answered:
If increased concentrations of greenhouse gases are capable of absorbing more infrared radiation in the lower troposphere, surely those increased concentrations are also capable of emitting more infrared from the upper atmosphere into space, thereby maintaining equilibrium?
All science-based answers devoid of ideology are welcome.
I’m doing my bit by consuming methane-emitting cows. Apparently it’s not working…