Study: methane leaks aren’t significant enough to negate value of natural gas

There’s a lot of hullabaloo recently about Natural Gas being too leaky to be a good substitute for coal. The claim is based on the fact that methane has a much larger GHG potential than carbon dioxide. But, the study those claims are based on can be interpreted two ways. I tend to think that the leak issue might be overblown, because if you are a producer, leaks mean money literally going into thin air. There’s a high incentive to fix leaks. Abandoned oil and gas wells, cited in the study, would of course be an exception.

The other reason is the IPCC, which produced this graph in the AR5 draft showing that methane just isn’t cooperating with models, and measurements are out of bounds with projections. Methane just doesn’t seem to be much of a problem:

IPCC_AR5_draft_fig1-7_methane

From The National Renewable Energy Laboratory:

JISEA News: Study on Methane Emissions from Natural Gas Systems Indicates New Priorities

Study findings published in Policy Forum of Journal Science

A new study published in the journal Science says that the total impact of switching to natural gas depends heavily on leakage of methane (CH4) during the natural gas life cycle, and suggests that more can be done to reduce methane emissions and to improve measurement tools which help inform policy choices.

Published in the February 14 issue of Science, the study, “Methane Leaks from North American Natural Gas Systems,” presents a first effort to systematically compare North American emissions estimates at scales ranging from device-level to continental atmospheric studies. Because natural gas emits less carbon dioxide during combustion than other fossil fuels, it has been looked to as a ‘bridge’ fuel to a lower carbon energy system.

“With this study and our larger body of work focusing on natural gas and our transforming energy economy, we offer policymakers and investors a solid analytical foundation for decision making,” said Doug Arent, executive director of the Joint Institute for Strategic Energy Analysis (JISEA) and a co-author to the study. “While we found that official inventories tend to under-estimate total methane leakage, leakage rates are unlikely to be high enough to undermine the climate benefits of gas versus coal.”

The article was organized by Novim with funding from the Cynthia and George Mitchell Foundation and led by Stanford University’s Adam Brandt. It was co-written by researchers from Stanford University, JISEA, Energy Department’s National Renewable Energy Laboratory (NREL), University of Michigan, Massachusetts Institute of Technology, National Oceanic and Atmospheric Administration, University of Calgary, U.S. State Department, Harvard University, Lawrence Berkeley National Laboratory, University of California Santa Barbara, and the Environmental Defense Fund.

“Recent life cycle assessments generally agree that replacing coal with natural gas has climate benefits,” said Garvin Heath, a senior scientist at the NREL and a lead author of the report. “Our findings show that natural gas can be a bridge to a sustainable energy future, but that bridge must be traversed carefully. Current evidence suggests leakages may be larger than official estimates, so diligence will be required to ensure that leakage rates are actually low enough to achieve sustainability goals.”

Among other key findings of the research:
• Official inventories of methane leakage consistently underestimate actual leakage.
• Evidence at multiple scales suggests that the natural gas and oil sectors are important contributors.
• Independent experiments suggest that a small number of “super-emitters” could be responsible for a large fraction of leakage.
• Recent regional atmospheric studies with very high emissions rates are unlikely to be representative of typical natural gas system leakage rates.
• Hydraulic fracturing is not likely to be a substantial emissions source, relative to current national totals.
• Abandoned oil and gas wells appear to be a significant source of current emissions.
• Emissions inventories can be improved in ways that make them a more essential tool for policymaking.

JISEA is operated by the Alliance for Sustainable Energy, LLC on behalf of the National Renewable Energy Laboratory, the University of Colorado – Boulder, the Colorado School of Mines, the Colorado State University, the Massachusetts Institute of Technology, and Stanford University.

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84 thoughts on “Study: methane leaks aren’t significant enough to negate value of natural gas

  1. We must study world wide flatulance. I’m sure NASA can launch a Satelite to figure it out. Sorry Latin America and Eastern Europe. I have a feeling you will be ostracized.

  2. What is the point of this hot air study? Methane leaks from man’s systems is minuscule. Even if it’s large it has helped to keep the global surface temps flat for over 16 years. Move along, nothing to see here. / sarc and zero worry

  3. Try filling the gap between dual glazed windows with methane. Just as when water vapour gets into that gap the insulating effect is reduced, so too does any radiating (so-called greenhouse) gas reduce the insulating because it expedites the transfer of heat across the gap. Likewise it expedites, rather than hinders, the escape of thermal energy up through the troposphere and out to space.

    If the gap between the panes is filled with dry air (as it usually is) or, better still, with non-radiating argon, then heat only transfers by molecular collisions, and this conduction-like process (which physicists call diffusion) is a relatively slow process as you can observe as you wait for heat to diffuse across a room from a convection heater on the other side. But of course radiated energy travels at the speed of light across the gap. But radiation only ever causes thermal energy to transfer from warmer to cooler regions. If it goes the other way, its electromagnetic energy is not converted to thermal energy and it is immediately re-emitted in a process physicists call pseudo scattering, because it looks the same as random scattering. So don’t worry about methane.

  4. OT
    National Geographic TV had on a deal with geologist and their study of the U.S. rocky mountains.
    Also one just before on volcanos and things on the molten rock 20 to 30 miles down most of the time yet up near surface to cause the volcanos and things like Yellowstone Park.
    The study in the rocky mountan deal had some info on the hot springs there having single cell life forms whose DNA is very, very close to that of the single cell life froms fround in the mid ocean vents discovered. Question from that , is there interconnections between oceans and land masses and land mass aquafiers we do not know any thing of yet.
    Now the thing is how much do we know of how much heat there is from this under foot heat, how does it move around the globe, does this movement of heat and things going on under foot but now seen have any effect on how the weather works.
    Seems we have little or no data from any study on this in corleation to climate.

    Not my field for sure, but it just seems the whole thing we live on is interconnected in ways we have little knowledge of.

  5. Obviously, we should abandon natural gas because it leaks occasionally.

    Everyone with natural gas heating, industrial uses, and electricity generation will have to switch to solar, wind or manure.

    You know, instead of fighting against these obviously outrageous false claims, maybe we should just exaggerate it even further and push for the even more ridiculous solutions. Because this is what these studies are really saying.

  6. In the Real World®, hydrocarbons break down far faster than these “experts” predict. Recall the BP disaster in the Gulf of Mexico, where the oil was predicted to make the gulf uninhabitable for the next century (or more, these idiots imply that the oil will remain there for the rest of eternity, which is quite the residence time indeed!).

    I appreciate, as well as anyone, that if you want to start a Model T, you have to crank (& crank & crank), but silly predictions of absurdly long residence times for volatile organic compounds, coupled with insane & unpossible long-term effects can’t even be effectively mocked anymore, they’re so overdone & meaningless. It’s like making fun of grandmas who knit ugly sweaters, or airline food.

  7. Small lakes in the area of Washington State where I live often have bubbles rising out of the bottom muck and floating lazily to the surface. Many of them are combustible (I’ve lit them afire…) so they must be methane or a near relative. This was also true in the area of Wisconsin where I grew up. Are they created out of rotting matter embedded in the lake bottom… or are they rising out of old coal seams or natural gas seeps that underlie these various parts south east of Seattle? A local state park is called ‘Flaming Geyser’ because of a natural gas seep that burned for many years. The village of Black Diamond is named for the local coal mining of yore. There used to be viable coal mines in this area… and there would be today, if local and state agencies didn’t make it prohibitively difficult to permit and operate them at a profit.

    As this area of ‘natural’ natural gas leaks is also somewhat urbanized, how would you use general ‘air’ trace gas sampling methods to discern the ‘natural’ natural gas leakage from the ‘bad man’ natural gas leakage?! How would you discern methane generated by cows or wet wood termites, both of which are in significant supply around here also?

    Methinks there are tooooo many leaks in this trial balloon to even raise their petard…. let alone keep it ahoist!

  8. In reply to;
    Col Mosby says:
    February 18, 2014 at 5:05 pm

    I thought methane was a short lived GHG.

    William: The CH4 molecule does have a short lifetime in the atmosphere 9 years. The level of CH4 in the atmosphere will therefore drop rapidly if the CH4 sources are reduced.

    The IPCC estimated that 26% of the CH4 in the atmosphere was due to the oil industry, 25% due to farm animals, and 16% due to cultivation of rice. The oil industry has been working to reduce CH4 emissions (CH4 is flared rather than vented to the atmosphere and better sealing techniques are used.) so much of the increase is maybe due to increases from other sources.

    http://www.atmosresearch.com/NCGG2a%202002.pdf

    “Methane has an atmospheric lifetime of 8.9±0.6 based on analyses of methyl chloroform and good knowledge of the loss rate with OH (Prinn et al., 1995). This is lower than the previous estimate of 10 years (WMO, 1991, 1995).

    In contrast to the numerous sources of methane, there are only one major and two minor sinks for tropospheric methane. Reaction with the hydroxyl radical (OH) is responsible for the removal of approximately 500 TgCH4/yr (almost 90% of the total sink), making the concentration of OH the most important determinant of the rate at which methane is destroyed.

    OH is formed from the photodissociation of tropospheric ozone and water vapour.”

  9. I remember a Nat Gas Leak study in 2012 or 2013 where they naively assumed the difference between gas at the well head and gas sold to customers was “Leaked”. Most of that difference, however was gas consumed by pipeline compression and pumping.

    Does anyone know whether this study has accounted for “consumed in operation” losses?

  10. The results of the most recent research supports the assertion that oil industry emission of CH4 is decreasing.

    http://www.globalcarbonproject.org/global/pdf/pep/Kirschke2013_3DecadesMethane.pdf

    “Although uncertainties in emission trends do not allow definitive conclusions to be drawn, we show that the observed stabilization of methane levels between 1999 and 2006 can potentially be explained by decreasing-to-stable fossil fuel emissions, combined with stable-to-increasing microbial emissions. We show that a rise in natural wetland emissions and fossil fuel emissions probably accounts for the renewed increase in global methane levels after 2006, although the relative contribution of these two sources remains uncertain.”

    “Overall, the three plausible scenarios, among many other possible source compositions matching global decadal changes, suggest that a decrease in fossil fuel CH4 emissions is a more likely explanation for the stability of global CH4 emissions between 1990 and 2005 than a reduction in microbial CH4 emissions. An actual decrease in rice paddy emissions may have been surpassed by an increase in other microbial emissions (natural wetlands, animals, landfills and waste) as found by ecosystem models combined with the EDGAR4.2 inventory. Considering the significant uncertainties reported in a recent isotope study59 for the 1990–2005 period, decreasing-to-stable fossil fuel emissions, combined with stable-to-increasing total microbial emissions, would reconcile the atmospheric ethane trends with the 13C-CH4 trends, at least for one 13C-CH4 data set59.”

  11. Natural gas and oil leaks were how the great oil/gas fields of the past were discovered. These leaks had been going on for millions of years at a high and consistent rate. It was only after the fields were drilled up and the reservoir bottom hole pressures dropped that the leaks abated.

  12. Given the fact that methane is 20X as potent a greenhouse gas as CO2, true believers in CAGW (Bill McKibben, et al.) should be clamoring for governments worldwide to capture methane from unstable deposits (like permafrost and hydrate deposits), and convert it to much less dangerous CO2. Capturing and burning natural gas (~95%+ methane) not only reduces its global warming potential, it provides cheap, clean energy. Additionally, empirical data from the last 17+ years shows CO2 is much more benign than previously believed. Climate model projections conclusively demonstrate that global temperatures simply do NOT correlate with CO2 levels.

    The silence/failure of these groups to advocate this truly ‘planet saving’ solution exposes their hypocrisy and/or their ignorance. It also shows that their goal is not to prevent methane releases to the atmosphere, it is to completely outlaw the production and use of all hydrocarbon fuels.

  13. Sweet Old Bob says:
    February 18, 2014 at 4:58 pm

    But…But… What about the COWS?
    I know, I know, ” Don’t have a cow, man”…
    ===============================================================

    But the cow is so tasty and delicious.

    What are the most numerous large animal species on the earth?

    The ones we raise for food. If you really want to preserve an endangered species, convince people that it tastes good.

  14. Why do the experts try to make it sound like natural gas and methane gas are two different things ?when natural gas is made up of 70 to 90% methane.

  15. Do a search on “Why is methane 20X as potent a greenhouse gas as CO2?”
    It’s an interesting answer.

  16. Thanks, Anthony! I just gave a classroom lecture on this topic, this is a very interesting graphic on methane contributions:

    Enteric fermentation (cow belches and farts) plus manure management actually exceed emissions from natural gas & petroleum systems!! Worldwide, methane emissions from rice paddy agriculture is a huge slice of the total, good luck doing something about that.

    http://www.news.ucdavis.edu/search/news_detail.lasso?id=10382

  17. Can’t for the life of me see how methane can be the monster ghg they claim. Yes the shorter wavelength photons are more energetic, but there’s fewer of them. So I don’t see how they get it to be 20 times as bad as CO2.

    The 288 K spectrum peak is 10.1 microns, so the 1% short end is 5.05 microns, and the ppm is very small.

    Not much solar at 6 microns, so very little solar warming from CH4 (atmospheric warming). If it get’s too much, then we can just burn the atmosphere for fuel.

  18. I don’t see any views here that disagree with your claims. You challenge conventional climate change science, but do you allow those scientists the opportunity to respond? If not, then I cannot see how this can be a serious nor honest scientific site that deserves to be taken seriously.

  19. People really should demand an explanation for why the Methane increases have been so much less than projected. This is part of the reason why models consistently predict too much warming. It seems like a blatant and bogus way to pump up projections of future warming to be more alarming.

  20. @george e. smith-The forcing is much larger on a per mass basis. But there is also several orders of magnitude difference in the amount of methane in the atmosphere compared to CO2. parts per billion versus parts per million. The stating of other gases being “stronger” than CO2 is highly misleading, since it obscures the fact that these gases aren’t equally abundant.

  21. Well I did a search on why ch4 is 20 x co2 and I got about 20 sites that said ch4 is 20x co2, and I found not one that said why. And they all said over 100 years. Hey if it’s 20x bad it is 20x for 20 minutes or 20,000 years. that time frame always grabs me.

    Like California’s desert wasteland solar mirror farm can light 140,000 houses per year. so that’s 14 million homes in 100 years, or it can only do 383 houses per day. What the hell does time have to do with it, it’s gigaWatts that counts.

  22. If it is a hydrocarbon based fuel, you can bet the warmists are against it. I am sure it is killing them the US CO2 emissions have been dropping for the last 6 years, largely as a result of switching from coal to nat gas for power gen, which in turn has been fueled by the huge increases in production from shale gas, which of course is nothing but good for the US economy. Link to emissions data :

    http://www.eia.gov/environment/emissions/carbon/

    This inconvenient fact totally gets in the away of their obsession with wind & solar & other “renewables” being the fuel we use to power our lives. I have no doubt that this is the motivation behind this paper – they have to show ALL hydrocarbons are bad, one way or the other, no matter what story they have to make up. This is completely biased “research”, IMHO.

  23. I am in natural gas exploration and development. I am in the process of building the entire operations and infrastructure for the complete build-out of a 100,000 acre field in the Marcellus
    Shale play. I can tell you that we have virtually NO loss of methane from any of our wells or gathering lines. We measure it continually throughout operations. And I agree that it would represent money out the window if it were occurring. Also, methane, even at relatively low concentrations at a well site can not be tolerated. We have some sites which have producing wells while we are actively drilling and fracing other wells. We can’t have stray methane at the well heads or in the ambient air. There are a wide range of ignition sources at a well drilling site and we can not afford to have stray gas losses. And it does not all of a sudden get worse once we are done and all wells go into production. The losses are LOW.

    What I can say is that in the land areas around natural gas plays there is a lot of loss of methane to the atmosphere by simple evaporation from shallow groundwater into the soil atmosphere and then into the actual atmosphere. We test every drinking water well in the areas surrounding all our well sites and we have found that about 5% of all wells contain methane as a result of natural methane in shallow formations (>100 m < 2,000 m) above our Marcellus target. It might seem small at each location measured, but if one were to take the flux in any averaged square kilometer and multiply that by the area of land above the gas-bearing formations in any area, the loss would be significant.

    I can't say too much about losses from gathering and transmission pipelines because I do not work for a mid-stream company. All I know is that our losses from the well heads to the compressor stations are very low to non-existent.

    In fossil fuel rich areas, at least in the Appalachian Basin, oil and natural gas are ubiquitous and there are losses to the atmosphere – we have to remember that oil was first discovered in an area of Pennsylvania (Titusville) near a stream name Oil Creek – because oil bubbles up naturally into the stream bed. That is in the west. As you move farther east in the basin, thermal maturity increases and there is more and more natural gas and it leaks to the atmosphere.

  24. I heard someplace that termites are the greatest source of methane in the atmosphere. Does anyone have data on this?

  25. @Alex Hamilton

    “But radiation only ever causes thermal energy to transfer from warmer to cooler regions. If it goes the other way, its electromagnetic energy is not converted to thermal energy and it is immediately re-emitted in a process physicists call pseudo scattering, because it looks the same as random scattering.”

    This is dangerously misleading, the way it is phrased. Being absorbed and ‘immediately re-emitted” necessarily involves thermalisation with the incoming energy adding to the total received from all sources by the hotter object. Many people make the mistake of confusing heat conduction with radiation, the latter being indiscriminate as to the direction it emits.

    Yes, a colder object will not cause the hotter one to gain more energy than it is losing, however it definitely reduces the rate of heat loss. Consider a hot object floating in space. It loses heat according to the standard radiation formula. Place a warm object near the hot one. The rate of heat loss from the hot one will be reduced by exactly the same amount of energy it receives from the warm object.

    Please edit any theory that relied on cooler objects not transferring energy to hot ones.

  26. Anthony, my read is that the natural gas vs coal warming potential is based mostly on a dispute over how much methane is leaking IN THE US. I say that because it is well known that methane is a stronger GHG than CO2, but that it doesn’t stay in the atmosphere nearly as long. The US environmental groups that are making a stink about natural gas not being substituted for diesel because the warming is greater with natural gas (which is methane) are doing so because they think that the methane leaks are pretty high. Their arguments are US-centric. Your graph above showing that worldwide methane emissions are less than projected carries no water with groups that think leaks are too big IN THE US, which is the source of only a small percentage of methane emissions from natural and human sources worldwide.

    Whether natural gas substituting for diesel emits more GHGs (methane and CO2, with appropriate warming potentials) is true or not depends on several factors, in addition to determining actual leak rates. If methane leaks are due to identifiable issues in the drilling, transmission, and distribution systems, then they could be fixed reasonably quickly. But suppose the leaks are from old oil and gas wells that were sealed many decades ago? Those leaks aren’t from present production, and someone will have to pay for finding and dealing with them, the original companies may no longer be in business. And in any case, those leaks will occur regardless of whether we drill more wells today or not.

    I’m not certain we know the division between leaks from abandoned oil and gas wells, vs. from the current usage system, across the US.

  27. Like John says:

    Methane is pretty much a non-issue. It has a persistence of a mere 11 years. Furthermore, it chemically abrades, there is no “shove aside” factor like for CO2.

  28. There is a lot of gas emitted in Washington and not all of it is from our Politicians,
    Why pick on just the enterprises that contribute to energy production

    http://www.npr.org/2014/01/16/262911327/aging-pipes-in-d-c-create-about-6-000-natural-gas-leaks

    “The nation’s capital is a pretty old city by American standards. It dates back to the late 18th century. Despite frequent face-lifts, parts of it are wearing out — for example, its underground gas pipelines. New research shows that Washington, D.C., suffers from thousands of leaks of natural gas.

    “We drove 1,500 road miles in Washington, D.C., and found about 6,000 leaks,” says Robert Jackson, an ecologist and environmental scientist at Duke University. “That’s roughly four leaks every mile.”

    Nathan Phillips looks at methane data plotted on a map of Boston streets on Nov. 17. Data from a mobile methane “sniffer” and a GPS show a real-time display of the gas levels in Google Earth. The orange spike in the center of the screen, on St. Paul Street, indicates methane levels about two or three times above normal levels, Phillips says.

    Four leaks per mile is even more than the scientific team found in Boston in 2011, where it did the same thing — drive the streets with a special instrument that detects methane (the main component in natural gas). In fact, the average amount of gas lost to leaks in Washington is more than twice the national average for cities.

    Jackson adds that at many sites he measured, the concentration of methane in the air was higher than anything he saw in Boston. And it’s not swamp gas. Jackson’s technique identifies the type of methane by its chemical structure and the presence of ethane and propane with it, forms of gas not usually found with the so-called biogenic methane created by rotting plants, bacteria and the like.

    In 12 cases, the gas concentration was potentially explosive. Jackson says he informed the local gas company about those early last year”.

  29. Compressor mechanic and Millwright by trade. A lot of the work I did was at landfills,
    most of which were on compressors or ICE’s generating power from the Methane.

    Ironically, I worked on a Sullair rotary screw gas compressor inside Manhattan Village, an
    exclusive gated community. A crapload of rich liberals living atop a landfill! It just does
    not get any better than this!

  30. “””””…..Crispin in Waterloo says:

    February 18, 2014 at 7:37 pm

    @Alex Hamilton

    “But radiation only ever causes thermal energy to transfer from warmer to cooler regions. If it goes the other way, its electromagnetic energy is not converted to thermal energy and it is immediately re-emitted in a process physicists call pseudo scattering, because it looks the same as random scattering.” …..”””””

    Helium is NOT a form of “heat”. Hydrogen and Oxygen are NOT forms of “heat”; neither are H2o, CO2 and CH4.

    Natural gas is NOT a form of “heat”, nor are petroleum or wood or coal. Soy Beans are NOT a form of “heat”, nor is uranium or iron a form of “heat”.

    Many of these things can store “heat” energy, such as H2O, CO2, and CH4, which you can “heat” in an oven, to temporarily store “heat”, but those ones lose heat very rapidly so that is not a good idea.

    Some of those things contain other forms of ENERGY that is NOT “heat”, but can be converted, at least partially into “heat” energy by combusting them, for example, soy beans can be burned to provide heat. So can CH4 and hydrogen, which work much better than soy beans, so does natural gas and petroleum, and coal also can be converted partly into heat to access the stored chemical energy in the coal.

    Electricity, and magnetism are NOT forms of heat, but electricity can be converted at least partly into “heat” by wasting it in a resistor. Electricity can also be used to create electromagnetic radiation energy, using LEDs; which is another form of energy, that like oil and coal is NOT “heat.

    A typical LED source of EM radiation, that is being kept ice cold, by a block of ice, can be fitted to a telescope and beamed at the sun, which is at about 6,000 kelvins, and the radiation will land on the sun anyway.

    The sun in turn, beams other forms of electromagnetic radiation energy, which is NOT a form of “heat”, all over the universe, including to the earth. The sun, neither knows, nor cares, whether the places it is sending EM radiant energy to in the universe, are colder, or hotter than the sun; it matters not a jot.

    Some of the EM radiant energy it sends to the earth can be collected by semi-conductor diodes of various materials, and converted to electricity, which is NOT a form of “heat”, but can be converted into heat by wasting it.

    Petroleum can also be turned into “heat” by wasting it, or it can be turned into plastics which can be used to wrap chunks of coal in to send to people who think electromagnetic radiation is a FORM OF “HEAT”.

    It isn’t a form of heat. We get no heat from the sun; we make all of it right here on earth, by wasting the radiant energy the sun gives us.

  31. “””””…..timetochooseagain says:

    February 18, 2014 at 6:49 pm

    @george e. smith-The forcing is much larger on a per mass basis. But there is also several orders of magnitude difference in the amount of methane in the atmosphere compared to CO2. parts per billion versus parts per million. The stating of other gases being “stronger” than CO2 is highly misleading, since it obscures the fact that these gases aren’t equally abundant……”””””

    I’m eager to learn. CO2 has a molecular weight of 44 (I think) and CH4 has a molecular weight of 16 (I think) so on a per molecule basis, ch4 is much less massive than co2 . Yes I get the parts per billion thing. Why don’t the folks who say it is 20x co2, simply show the full set of figures that prove that. They don’t even show the IR absorption spectra of the two of them, or with H2O as well, which is mole wt. 18 (I think), so similar to ch4, but a gazillion times more of in the atmosphere. What is the energy captured per molecule from a 288 K LWIR source ?

  32. Alex Hamilton says:
    February 18, 2014 at 5:05 pm
    Try filling the gap between dual glazed windows with methane. Just as when water vapour gets into that gap the insulating effect is reduced, so too does any radiating (so-called greenhouse) gas reduce the insulating because it expedites the transfer of heat across the gap. Likewise it expedites, rather than hinders, the escape of thermal energy up through the troposphere and out to space.

    Loving this. My wheelhouse is the moon Titan, with it’s 5% methane atmosphere, methane rain from methane clouds, and pools of liquid C4, some as large as Lake Superior.

    It has zero global warming effect. In fact it acts exactly like Alex describes.
    In the astronomical community even ersat global warming supporters describe Titan as having an anti-greenhouse effect because of methane.

    Titan: Greenhouse and Anti-greenhouse

    Consider a hot object floating in space, indeed.

  33. chris donnolley says:
    February 18, 2014 at 6:43 pm

    I don’t see any views here that disagree with your claims. You challenge conventional climate change science, but do you allow those scientists the opportunity to respond? If not, then I cannot see how this can be a serious nor honest scientific site that deserves to be taken seriously.

    Did you have to join,log in, fill out a membership form, send money, pay a fee, subscription to post this?

    We do occasionally get “conventional climate change scientists” in here, usually bloviating and spouting the same calamatology, Mosh is an exception though, but this site is freely open to anyone that wants to post.

    Your question was?

  34. george e. smith
    Why don’t the folks who say it is 20x co2, simply show the full set of figures that prove that.
    >>>>>>>>>>

    They did, but my link to the paper was two computers ago. Best as can recall, they got to 20x by assuming that CH4 gets oxidized to CO2 and H2O*2. They then add the additional CO2 long term effects to the CH4 short term effects, plus there was some mathematical gymnastics around the H2O being created at altitude where water vapour otherwise would not exist and hence would have more effect than water vapour from evaporation. They wrapped the whole thing up in a mess of charts and graphs claiming “Global Warming Potential” of 20x using all those factors combined.

    They actually ended the paper by suggesting that methane might be controlled by putting a tax on pork, beef and milk in order to curb production of methane. Yup, tax the food, that’ll help curb world hunger!

  35. Crispin is probably not aware of recent papers in physics literature that talk about pseudo scattering of radiation from a colder source when it strikes a warmer target. What I said is now considered correct, and the electromagnetic energy is immediately re-used in that form for part of the Planck emission by the warmer surface. So the warmer surface cools more slowly, but never actually receives additional thermal energy. If it did receive extra thermal energy then it could indeed stay momentarily hotter, even for a few seconds, and it would have no obligation to lose that thermal energy by radiation. For example, if radiation warmed a layer of water below the surface, it might rise and evaporate a few seconds later. The extra energy would not “remember” it came from radiation. Hence there would have been a one way independent process that would have transferred thermal energy from a colder to a warmer body, thus decreasing entropy. This cannot happen, so the radiation is in fact merely pseudo scattered by the surface and immediately comes back out with the same frequencies and intensities, in other words, the same Planck distribution which is in fact a subset of the Planck distribution for the warmer surface.

  36. Does it never occur to anyone that if the natural gas was not extracted 100% would have to leak or there would be a pressure build up till it self ignited as in a diesel engine? In reality there are several known escape points like the one in Russia they ignited expecting it to burn out in days that is still burning several years later, as well as millions more small ones probably . Most bog areas are non stop quietly emitting methane and totally ignored in the climate models just as if the rates were fixed rather than variable as are all other natural sources.

  37. chris donnolley says:
    February 18, 2014 at 6:43 pm

    “I don’t see any views here that disagree with your claims. You challenge conventional climate change science, but do you allow those scientists the opportunity to respond? If not, then I cannot see how this can be a serious nor honest scientific site that deserves to be taken seriously.”
    —-l
    Interesting handle. Do you also agree with the claims made here? If not, here is your golden opportunity to voice a dissenting opinion – preferably motivated by reason rather than emotion.

    If you are new here and want to be taken seriously, I strongly suggest you read the site policy under the about tab before posting any further comments. You might also want to peruse the archives. Try to avoid vague generalisations.

  38. Reblogged this on planetvoice and commented:
    Methane in the gas system is a problem or not? Replacing of coal with natural gas has really climate benefits? Recent studies help us to form new way to thinking about climate change and GHG effect.

  39. The GHG problem is not a problem. Methane oxidizes to CO2 and H2O using up oxygen. Thankfully photosynthesis converts the CO2 and H2O to sugar and Oxygen.

  40. Since my first over zealous comment I have found out that humans are responsible for most of the methane emissions. Annual emissions 320 million tonnes. On a global scale this is a negligible number – not impressed.

    IPCC projections V observations. Nothing to see here.

  41. chris donnolley says:
    February 18, 2014 at 6:43 pm

    I don’t see any views here that disagree with your claims. You challenge conventional climate change science, but do you allow those scientists the opportunity to respond? If not, then I cannot see how this can be a serious nor honest scientific site that deserves to be taken seriously.

    ==================

    Scientists are free to respond to anything Mr Watts posts here and some of them do.

    What exactly is ‘conventional’ climate change science?

  42. If you want control of the masses, you teach children something is bad and in 15 or 20 years they willingly hand over control of it. The AGW crowd started with CO2 which is now called carbon pollution. Now we start with methane and treat it as a dirty nasty pollutant. The science doesn’t really matter, you just have to say it long enough and loud enough to make it stick in the mind of a child.
    You can win every battle over the science and still lose the war because of the propaganda. Once children are taught something is dirty and bad, very few will ever see those things as something natural and useful.
    What does a 10 year old picture in their mind when they hear carbon pollution, dead polar bears and nasty black smoke stacks. Methane is now shown as flaring and white smoke stacks to every child. That is the war the AGW crowd is fighting.

  43. One study I read stated that 40% of global methane production comes from rice cultivation.

    One reason methane is not cooperating is that water management techniques for wet rice production have changed in some parts of the world. http://www.nature.com/news/2009/090818/full/news.2009.833.html‎

    Seems if you use less water you get less methane and greater tonnage of rice. Plus there is more land available than water. So it makes sense to increase land under cultivation and change water management techniques to spread the water usage over more area.

  44. It should be easy to determine how much of the CH4 in the atmosphere comes from natural gas and how much from cows, rice-paddies, swamps etc. CH4 from organic sources will contain radiocarbon (C14), fossil CH4 won’t.

  45. Anthony,

    That chart comparing CH4 model projections to observations is a killer, but where does it come from? Without a link to verify source, I CAN’T USE IT! Please kindly supply link or reference. Thanks.

  46. I don’t understand. Methane absorbs radiation in the 7.6um band. That’s 381K or 226.13F. So what’s the problem with it being a GHG? What danger does it represent in the atmosphere? it doesn’t absorb in the same bands that earth emits (220K/-63.67F to 320K/116.33F). Seems to me the big problem is underground mines, where heat could cause an explosion.

    [Ron Manley says:, February 18, 2014 at 5:18 pm. You wrote about CO4: "It is also at a point in the spectrum where long-wave energy is half that of the much wider band where CO2 operates." CO2 operates around 13.5um-15um (214K/-74.47F to 193K/-112.27F). Doesn't the long-wave radiation get stronger with a smaller micron number? Or am I not understanding you? http://www.astro.virginia.edu/~mfs4n/ir/light_em_spectrum.jpg ]

  47. chris donnolley says:
    February 18, 2014 at 6:43 pm

    I don’t see any views here that disagree with your claims. You challenge conventional climate change science, but do you allow those scientists the opportunity to respond? If not, then I cannot see how this can be a serious nor honest scientific site that deserves to be taken seriously.

    Why don’t you wait for an answer to your question before loading the balls in the cannon? Better yet, read the archives, or search for your favorite ‘conventional climate change scientist’ to see if he or she was treated fairly or scientifically.

  48. tty says:
    February 19, 2014 at 7:35 am

    It should be easy to determine how much of the CH4 in the atmosphere comes from natural gas and how much from cows, rice-paddies, swamps etc. CH4 from organic sources will contain radiocarbon (C14), fossil CH4 won’t.

    It’s fairly simple to determine the proportion, but since we only have poor estimates on the actual volumes emitted (this is because the emissions estimates are calculated from bizarrely long residence-time calculations, which are themselves based on the poor emissions estimates) it’s basically impossible to get at the amounts.

  49. This is beyond belief. Do these fools think that gas mains, installations and pipelines are the same as water mains?

  50. In the hope of eliminating, or at least slowing down, wasteful, inane studies like this one, I propose that all universities, colleges, “green” energy companies, “green” think tanks, and the offices of all elected democrat politicians can only be heated, cooled and lighted by energy produced by “renewable” sources.

  51. chris donnolley says:
    February 18, 2014 at 6:43 pm

    I don’t see any views here that disagree with your claims. You challenge conventional climate change science, but do you allow those scientists the opportunity to respond? If not, then I cannot see how this can be a serious nor honest scientific site that deserves to be taken seriously.
    ———————
    You wouldn’t happen to be ‘waxliberty’, by any chance, would you? I have been in a dialogue with him over the last 5 days on a CNN article. I had suggested to him that he should voice his opinion here if he really had something to say other than denigrating anything that is even remotely related to this site.

    Either way what a classic example of saying less than absolutely nothing. Do you have any thoughts in regards to the premise and intent of the post itself? I am a gambler. I would bet that I am right in this regard.

  52. Tom G(ologist) says:
    February 18, 2014 at 7:05 pm
    —————————————
    That is excellent information for an argument in a debate.

  53. “”””””…….davidmhoffer says:

    February 18, 2014 at 10:14 pm

    george e. smith
    Why don’t the folks who say it is 20x co2, simply show the full set of figures that prove that.
    >>>>>>>>>>

    They did, but my link to the paper was two computers ago. ……..””””

    Thanks much David. Your lucid recap, fully explains why the hell I never could make head nor tail of it. I put it alongside “Murder on the Orient Express.” as one of the most baffling whodunit tales of all time.

    Thanx again.

    g

  54. From “the science is settled dept.”

    Several posters above refer to estimates of the GHG potential of CH4 as being 20 times that of CO2 (without clarity as to whether this is per mole or per tonne of gas). This report of the present study refers to a Cornell paper that claims the factor is 72 on a 20 year horizon:

    http://www.carbonbrief.org/blog/2014/02/natural-gas-emissions-are-being-underestimated-new-study/

    while the UNFCCC quotes a factor of 56 for a 20 year horizon (allowing for the daughter products of chemical decay), and 21 for 100 years, again without stating the basis for relativity:

    http://unfccc.int/ghg_data/items/3825.php

    Wikepedia clarifies that GWPs are measured relative to mass, and then goes on to quote the variations in estimates over recent IPCC reviews. For CH4, they estimated 62 in 2001, 72 in 2007 and 86 in 2013, with the 100 year factors rising from 23 to 25 to 34.

    http://en.wikipedia.org/wiki/Global-warming_potential

    The use of mass is a peculiarity, given that the Boyle’s Law gas equation is couched in molar fashion:

    PV=nRT

    Is this more Political Science?

  55. Policycritic:

    Blackbody radiation occurs at all wavelengths, not just the temperature of the peak, in accordance with Planck’s Law:

    http://en.wikipedia.org/wiki/Planck%27s_law

    Molecular absorption and emission is split between relatively sharply defined spectral lines that are associated with transitions between different quantum energy levels of electron orbits, and rather broader ones that are the absorption of energy by vibration modes of the molecule, where is behaves rather like masses on springs for the molecular bonds – indeed for simple molecules you can get a good first approximation by modelling them as exactly that, using Hooke’s Law and simple harmonic motion equations.

  56. “Why is “CH4 20X as potent a greenhouse gas as CO2?”

    Wow! I thought for sure some one would come up with it.

    This is an issue that illustrates the point that propagandists can assert B.S. with an authoritative voice and get away with it.

    This website is regularly populated by some very smart people and yet here we all are flailing around not knowing why CH4 is 20X as potent a greenhouse gas as CO2, yet it seems to be taken as a matter of faith that it is. Begs the question as to what else is being swallowed whole hog without nary a thought about the validity of what’s being claimed under the mantle of scientific authority.

    I did the search some time ago, and I did get an answer that sort of made sense, but really needs some discussion to flesh it out. But, I’m going to be coy about it for a while. Don’t like that? Sue me (-:

    Maybe Anthony knows and he’s just sitting back watching.

  57. “Wow! I thought for sure some one would come up with it.

    This is an issue that illustrates the point that propagandists can assert B.S. with an authoritative voice and get away with it.

    This website is regularly populated by some very smart people and yet here we all are flailing around not knowing why CH4 is 20X as potent a greenhouse gas as CO2, yet it seems to be taken as a matter of faith that it is. ”

    See the document I linked to. it’s not that complicated.

  58. Steve Case says:
    This website is regularly populated by some very smart people and yet here we all are flailing around not knowing why CH4 is 20X as potent a greenhouse gas as CO2
    ———————————————————————————————-
    Isn’t that what makes this site so great? There is no assumption of knowing it all, or let’s all settle on this explanation and call it a day. Rather, the thought always leads to ‘how can we flesh this out?’, and by sharing the bits and pieces of relevant information that might lead to the spark of realization and discovery. The other side does the opposite.

  59. Mosher at 7:07

    Your link says it’s because CH3 oxidizes to CO2.

    OK. I hadn’t read your link

    The answer I got some time ago, perhaps a year or more, was that it’s because there isn’t much CH3 in the atmosphere. What ever climate sensitivity it has, it doesn’t take much to result in a doubling of CH3 concentration. So a small increase will run the temperature up more than CO2 would simply due to the fact that its concentration would double sooner.

  60. @papiertigre-Yes, this has become a bit of a problem for efforts to resolve the faint young sun paradox: at sufficiently high levels of methane in the atmosphere you actually start to get an organic haze that develops and causes a cooling effect. We are nowhere near the level of methane that would form a haze.
    @george e. smith-I don’t think you full grasp just how many more molecules a part per billion is versus a part per million. There are something like 1.09*10^44 molecules in the atmosphere. Methane is roughly 2 parts per million, something like 2.18e+38 molecules. CO2 is roughly 400 parts per million 4.36e+40 parts molecules. Taking into account their molecular weights, all the CO2 in the atmosphere has about 12 times as much mass as CH4. The 20 times figure no longer seems so impressive, since it would require the amount of CH4 to increase 12 fold to actually be 20 times as large as the effect of the amount of CO2.

  61. “””””…..timetochooseagain says:

    February 19, 2014 at 9:47 pm
    ……………………………
    @george e. smith-I don’t think you full grasp just how many more molecules a part per billion is versus a part per million. …..”””””

    Well don’t look at me; twas you that mentioned “parts per billion”, not me.

    And as it happens; I’m quite sure that YOU…..””..don’t fully grasp just how many more molecules a part per billion is versus a part per million. …..”””””

    I figured out half a century ago that it was 0.001 !

  62. Since methane is more potent a GHG than co2, perhaps if we leak methane through our engines converting it to the less potent co2 first? Net gain? Maybe the cash for clunkers money or a fraction of the billions wasted on bankrupt green companies bought up by China at pennies on the dollar would have been better spent on cng conversion R&D?

  63. It doesn’t add up…:

    At February 19, 2014 at 5:52 pm you say

    Policycritic:

    Blackbody radiation occurs at all wavelengths, not just the temperature of the peak, in accordance with Planck’s Law:

    http://en.wikipedia.org/wiki/Planck%27s_law

    Molecular absorption and emission is split between relatively sharply defined spectral lines that are associated with transitions between different quantum energy levels of electron orbits, and rather broader ones that are the absorption of energy by vibration modes of the molecule, where is behaves rather like masses on springs for the molecular bonds – indeed for simple molecules you can get a good first approximation by modelling them as exactly that, using Hooke’s Law and simple harmonic motion equations.

    Blackbody radiation in the atmosphere is so small relative to greenhouse gas (GHG) radiative effects that it is usually ignored. Simply, blackbody radiation in the atmosphere is so trivial that it can be considered to be zero for all practical considerations.

    The blackbody radiative effect occurs within the individual atoms of molecules. When an atom absorbs a photon then it gains the energy of the photon by raising an electron to a higher energy state (i.e. a higher ‘shell’).

    The greenhouse effect (GHE) occurs by changing the energy of entire molecules and NOT the energy of electrons within atoms which are parts of molecules.

    I explain this as follows.

    A photon is a quantum of electromagnetic (EM) radiation which has a wavelength related to the energy it carries. When it is absorbed by a GHG molecule then it increases the vibrational or the rotational or the stretching energy of the molecule.

    The effects are quantised by the shape of the molecule and its bonds. Hence, vibrational absorbtion is possible for a CO2 molecule
    C – O – C
    Because the ‘angle’ between the C atoms attached to the O atom can change to provide the vibration.
    But such vibrational excitation cannot occur to an O2 molecule (or an N2 molecule)
    O – O
    Because the molecule has no ‘angle’ to change.

    Please note that a gas does not get hotter when its GHG molecules absorb photons.

    The heat of a gas is expressed by its temperature which is an indication of the average speed (actually RMS speed) of the gas molecules. Increase the average speed of the molecules and the gas gets hotter. Decrease the average speed of the molecules and the gas gets cooler.

    A GHG molecule gains energy but does not get hotter when it gets excited by absorbing a photon: it is raised to a higher quantum level (by increasing the vibrational or rotational energy of the molecule). Simply, the energy from the photon is stored in the GHG molecule and the GHG molecule does not change its speed. If that stored energy is supplied by a collision to e.g. a nitrogen molecule then the nitrogen molecule is accelerated: the energy that was stored in the GHG molecule becomes kinetic energy in the nitrogen molecule so the gas gets hotter.

    Similarly, if a collision causes kinetic energy of a nitrogen molecule to be transferred to be stored in a GHG molecule then the gas is cooled because the nitrogen molecule is decelerated but the GHG molecule is not accelerated. However, this is an extremely improbable event as the collision would have to occur so as to transfer the energy into e.g. a vibrational mode only, the cross section for this event would be very small. Most of the collisions would transfer mostly translational energy, next likely rotational and least likely vibrational or stretching.

    I hope this helps.

    Richard

  64. Richard:

    A diatomic molecule can absorb energy in a vibration mode that alters its bond length.

    O-O O–O O—O O–O O-O

    In addition, it has two rotational degrees of freedom corresponding to spinning end over end where the z axis is the molecular axis (think of it as in the plane of the screen, and perpendicular to the screen): such rotations can store energy that is not reflected in temperature, which depends on the (root mean square) speed of the centre of mass of the molecules in the gas. For Oxygen, taking 16 g/mol, the weight per atom is about 2.66E-26 kg. At 273K, the rms velocity is 461 m/s – an average energy of about 5.65 E-21 J per molecule. It has an absorption band at around 6 microns, which is an energy of 3.27E-20 J per photon and a frequency of 50 THz. The molecular dissociation energy is 498kJ/mol O2, or 8.27 E-19 J per molecule – or about 0.23 microns/230nm, which is in the hard UV spectrum. When a molecule is excited in one (or more) of these energy stores and it passes within range of another molecule (“collides”), it can kick out like a punch that sends the other molecule flying away faster, while reducing the energy stored in its own rotation or vibration and so conserving energy.

    The following gives a nice introduction to the absorption bands of the main atmospheric gases:

    http://irina.eas.gatech.edu/EAS8803_Fall2009/Lec6.pdf

    Note that the UV absorption of O3 is by electron energy changes, not molecular vibrational modes.

  65. It doesn’t add up… :

    re your post at February 20, 2014 at 8:15 am.

    Yes, a diatomic molecule can obtain photonic excitation by bond stretching but this is not pertinent to what happens in the atmosphere. As I said, a photon of EM has a wavelength which related to its energy and it is absorbed when there is an available quantum excitation state of an absorbing atom or molecule.

    There is no doubt that GHG molecules are orders of magnitude more important for radiative absorbtion than diatomic molecules in the atmosphere. If you could falsify this then you would surely obtain a Nobel Prize for physics because you would overturn much knowledge and open up vast areas of useful research.

    And the ozone issue is not relevant except in polar regions.

    Richard

  66. Richard:
    Absorption will take place whenever there are photons that match an absorption band. Most atmospheric gases are transparent – i.e. do not absorb – in visible wavelengths that correspond to the more intense levels of solar radiation (but note the UV exception for ozone in particular): their absorption is dominated by IR wavelengths, as my link shows. The sun also radiates in the IR, albeit not as strongly as in the visible spectrum. IR energies are concerned with the motions of atoms in molecules, not electron orbit transfers between different energy levels. For practical purposes, quantisation is not relevant at these energies, because the quantised levels are so close together (and broadened via a variety of mechanisms) they represent a continuum. The Newtonian approximation suffices quite well: you can consider wave/particle duality of photons as the driver of what becomes fundamentally a mechanical system after absorption. Broad resonance peaks behave much as those for a simple driven pendulum or RC electrical circuit fed an AC voltage at varying frequencies – this is quite unlike the energy transitions for electrons in a molecular system, where the peaks are much more sharply defined, and mainly subject to fine structure splitting.

    If you actually looked at the reference I cited, you would see that I am not trying to overturn the measured absorption spectra, but merely to illustrate the different physical phenomena involved.

    An introduction to molecular vibrations:

    http://en.wikipedia.org/wiki/Molecular_vibration

    A more advanced treatment does look at the superposition of different quantum states arising from rotations and vibrations.

    In the context of my original post on this topic I was responding to Policycritic, who appeared to consider that blackbody/graybody radiation only occurs at the wavelength given by Wien’s Law for the peak or characteristic wavelength. I don’t understand why you even chose to respond in the manner you did, introducing several errors along the way. The reason why GHGs heat up is because they absorb radiation in the first place: that radiation is a combination of the earth’s “blackbody” radiation and “blackbody” radiation from the sun and radiation scattered/emitted in the atmosphere. There is no magic transition between photons that excite electrons into different orbits and photons that cause changes in the vibration of molecules. The same energy of photon may have different effects. Photons generated by blackbody radiation are no different from photons generated when an atom, particle or molecule emits via other mechanisms. All photons have the same flavour, only distinguished by their energy/wavelength/frequency as described by E=hv=hc/λ. You implied that there were no absorption modes for O2, when there are, and that the only absorption mode for CO2 is scissoring of the bond angle, ignoring synchronous and asymmetric bond stretching.

  67. Richard

    i agree with most of what you write, but you appear to have overlooked the Equipartition Theorem.

    In my opinion, rotational and vibrational energy is also a form of kinetic energy that can be passed on in molecular collisions and which does affect temperature measurements. I know there are divided opinions on this, so you are sure to find someone saying otherwise. But, either way, an increase in these degrees of freedom must then be shared with the translational DoF’s as well.

  68. It doesn’t add up… :

    Among other errors in your post at February 20, 2014 at 5:48 pm you assert to me

    I don’t understand why you even chose to respond in the manner you did, introducing several errors along the way. The reason why GHGs heat up is because they absorb radiation in the first place: that radiation is a combination of the earth’s “blackbody” radiation and “blackbody” radiation from the sun and radiation scattered/emitted in the atmosphere.

    THE “ERRORS” ARE YOURS! Indeed, the reason I wrote was to correct some of your errors.

    For example, in the brief quotation I here provide you write

    The reason why GHGs heat up is because they absorb radiation in the first place

    I had explained that GHG’s DON’T “HEAT UP” when I wrote

    A GHG molecule gains energy but does not get hotter when it gets excited by absorbing a photon: it is raised to a higher quantum level (by increasing the vibrational or rotational energy of the molecule). Simply, the energy from the photon is stored in the GHG molecule and the GHG molecule does not change its speed. If that stored energy is supplied by a collision to e.g. a nitrogen molecule then the nitrogen molecule is accelerated: the energy that was stored in the GHG molecule becomes kinetic energy in the nitrogen molecule so the gas gets hotter.

    Richard

  69. Alex Hamilton:

    Your post at February 20, 2014 at 7:58 pm begins says to me

    i agree with most of what you write, but you appear to have overlooked the Equipartition Theorem.

    In my opinion, rotational and vibrational energy is also a form of kinetic energy that can be passed on in molecular collisions and which does affect temperature measurements. I know there are divided opinions on this, so you are sure to find someone saying otherwise. But, either way, an increase in these degrees of freedom must then be shared with the translational DoF’s as well.

    NO! I did not ignore the Equipartition Theorem.

    It is a matter of reality – n.b. NOT a matter of opinion – that internal energy of a molecule is NOT kinetic energy of a molecule. I explained that such internal energy can be transferred to other molecules and, thus, become kinetic energy (i.e. heat) of the gas.

    Simply,
    (a) radiative absorbtion increases the energy in a gas but does NOT heat the gas.
    However,
    (b) collisions between molecules can transfer the absorbed energy such as to convert that energy to kinetic energy with resulting heating of the gas.

    I stated this when I wrote

    A GHG molecule gains energy but does not get hotter when it gets excited by absorbing a photon: it is raised to a higher quantum level (by increasing the vibrational or rotational energy of the molecule). Simply, the energy from the photon is stored in the GHG molecule and the GHG molecule does not change its speed. If that stored energy is supplied by a collision to e.g. a nitrogen molecule then the nitrogen molecule is accelerated: the energy that was stored in the GHG molecule becomes kinetic energy in the nitrogen molecule so the gas gets hotter.

    Similarly, if a collision causes kinetic energy of a nitrogen molecule to be transferred to be stored in a GHG molecule then the gas is cooled because the nitrogen molecule is decelerated but the GHG molecule is not accelerated. However, this is an extremely improbable event as the collision would have to occur so as to transfer the energy into e.g. a vibrational mode only, the cross section for this event would be very small. Most of the collisions would transfer mostly translational energy, next likely rotational and least likely vibrational or stretching.

    Hence, I am surprised that you think I “overlooked the Equipartition Theorem”.

    The important point I tried to explain is that the warming of non-GHG molecules results from the photonic absorbtion by GHG molecules and would not occur in the absence of GHG molecules.

    My purpose was not to attempt the impossible task of explaining this entire field of quantum behaviour and there is much, much more than the Equipartition Theorem which I have not explained.

    Richard

  70. Richard

    Nitrogen and oxygen molecules (and GHG ones too) are warmed by conduction at the surface / atmosphere boundary. GHG molecules absorb and emit radiation, but also receive and impart kinetic energy in collisions with any other molecules. So they act like holes in the blanket getting rid of surplus thermal energy that is being absorbed by the atmosphere or energy that has been transferred into the atmosphere as sensible (non-radiative) energy. That is why you don’t use moist air between the panes of double glazed windows – it reduces the insulating effect.

    When radiation strikes a target what happens depends on the relative temperatures of the source of spontaneous radiation and the target. I trust we don’t disagee that the electro-magnetic energy in direct solar radiation from the Sun does warm Earth’s surface. So its energy is converted to thermal (kinetic) energy in surface molecules. The Equipartition Theorem tells us this new kinetic energy will end up being shared equally between the degrees of freedom (DoF) which comprise three translational DoF’s and more DoF’s which are vibrational and rotational kinetic energy. You seem to think the latter can have different values to those of each translational DoF, but you will need to get through an edit for Wikipedia to convince others, though not myself.

    Now, the reason molecules only emit and absorb photons of particular wavelengths is that there must be changes in electron energy which exactly match the energy in the photon. If the radiation comes from a cooler source it merely resonates with a warmer target that is already emitting equivalent radiation as a part of its Planck spectrum. We can think of the energy momentarily changing an electron state and then that state immediately reverting back to its initial state as it emits an equivalent photon back out again. Physicists call the process “pseudo scattering” because it looks as if the incident radiation was just randomly scattered – rather like diffuse reflection. The energy did not go through the complicated internal process of being converted to thermal (kinetic) energy shared equally among those other degrees of freedom.

    But if the source of radiation had been hotter than the target, then some of its radiation (corresponding to the area between the Planck curves) does not resonate and its energy is converted to thermal (kinetic) energy, and so the Sun can warm the surface, but back radiation can only slow down that portion of surface cooling which is itself by radiation.

    Kinetic energy is shared in molecular collisions (heat diffusion) and when some molecules become significantly “hotter” than others around, the kinetic energy may firstly raise the energy state of an electron and that then leads to emission of a photon. So sensible energy transfers from the surface to the atmosphere, as well as absorption of radiation by the atmosphere (including nearly a fifth of all incident solar radiation) does firstly warm the atmosphere, and then radiating molecules also get warmed by sensible heat transfer (diffusion) and energy is radiated in all directions. That radiation which strikes a warmer target is pseudo scattered, and eventually all the radiated energy gets to cooler regions and then to space. However, there is a limit to the cooling (which continues into the night) because the Sun starts more warming the next day and radiative balance is automatically maintained because the whole Earth+atmosphere system acts like a black body.
    .

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