Methane emitted by humans vastly underestimated, researchers find

University of Rochester

Methane emitted into the atmosphere can be sorted into two categories, based on its signature of carbon-14, a rare radioactive isotope. Fossil methane has been sequestered for millions of years in ancient hydrocarbon deposits and no longer contains carbon-14; biological methane is in contact with plants and wildlife on the planet's surface and does contain carbon-14. Biological methane can be released naturally from sources such as wetlands or via anthropogenic sources such as landfills, rice fields, and livestock. Fossil methane can be emitted via natural geologic seeps or as a result of humans extracting and using fossil fuels. Credit University of Rochester illustration / Michael Osadciw

Methane emitted into the atmosphere can be sorted into two categories, based on its signature of carbon-14, a rare radioactive isotope. Fossil methane has been sequestered for millions of years in ancient hydrocarbon deposits and no longer contains carbon-14; biological methane is in contact with plants and wildlife on the planet’s surface and does contain carbon-14. Biological methane can be released naturally from sources such as wetlands or via anthropogenic sources such as landfills, rice fields, and livestock. Fossil methane can be emitted via natural geologic seeps or as a result of humans extracting and using fossil fuels. Credit University of Rochester illustration / Michael Osadciw

Methane is a powerful greenhouse gas and large contributor to global warming. Methane emissions to the atmosphere have increased by approximately 150 percent over the past three centuries, but it has been difficult for researchers to determine exactly where these emissions originate; heat-trapping gases like methane can be emitted naturally, as well as from human activity.

University of Rochester researchers Benjamin Hmiel, a postdoctoral associate in the lab of Vasilii Petrenko, a professor of earth and environmental sciences, and their collaborators, measured methane levels in ancient air samples and found that scientists have been vastly underestimating the amount of methane humans are emitting into the atmosphere via fossil fuels. In a paper published in Nature, the researchers indicate that reducing fossil fuel use is a key target in curbing climate change.

“Placing stricter methane emission regulations on the fossil fuel industry will have the potential to reduce future global warming to a larger extent than previously thought,” Hmiel says.

TWO TYPES OF METHANE

Methane is the second largest anthropogenic–originating from human activity–contributor to global warming, after carbon dioxide. But, compared to carbon dioxide, as well as other heat-trapping gases, methane has a relatively short shelf-life; it lasts an average of only nine years in the atmosphere, while carbon dioxide, for instance, can persist in the atmosphere for about a century. That makes methane an especially suitable target for curbing emission levels in a short time frame.

“If we stopped emitting all carbon dioxide today, high carbon dioxide levels in the atmosphere would still persist for a long time,” Hmiel says. “Methane is important to study because if we make changes to our current methane emissions, it’s going to reflect more quickly.”

Methane emitted into the atmosphere can be sorted into two categories, based on its signature of carbon-14, a rare radioactive isotope. There is fossil methane, which has been sequestered for millions of years in ancient hydrocarbon deposits and no longer contains carbon-14 because the isotope has decayed; and there is biological methane, which is in contact with plants and wildlife on the planet’s surface and does contain carbon-14. Biological methane can be released naturally from sources such as wetlands or via anthropogenic sources such as landfills, rice fields, and livestock. Fossil methane, which is the focus of Hmiel’s study, can be emitted via natural geologic seeps or as a result of humans extracting and using fossil fuels including oil, gas, and coal.

Scientists are able to accurately quantify the total amount of methane emitted to the atmosphere each year, but it is difficult to break down this total into its individual components: Which portions originate from fossil sources and which are biological? How much methane is released naturally and how much is released by human activity?

“As a scientific community we’ve been struggling to understand exactly how much methane we as humans are emitting into the atmosphere,” says Petrenko, a coauthor of the study. “We know that the fossil fuel component is one of our biggest component emissions, but it has been challenging to pin that down because in today’s atmosphere, the natural and anthropogenic components of the fossil emissions look the same, isotopically.”

TURNING TO THE PAST

In order to more accurately separate the natural and anthropogenic components, Hmiel and his colleagues turned to the past, by drilling and collecting ice cores from Greenland. The ice core samples act like time capsules: they contain air bubbles with small quantities of ancient air trapped inside. The researchers use a melting chamber to extract the ancient air from the bubbles and then study its chemical composition.

Hmiel’s research focused on measuring the composition of air from the early 18th century–before the start of the Industrial Revolution–to the present day. Humans did not begin using fossil fuels in significant amounts until the mid-19th century. Measuring emission levels before this time period allows researchers to identify the natural emissions absent the emissions from fossil fuels that are present in today’s atmosphere. There is no evidence to suggest natural fossil methane emissions can vary over the course of a few centuries.

By measuring the carbon-14 isotopes in air from more than 200 years ago, the researchers found that almost all of the methane emitted to the atmosphere was biological in nature until about 1870. That’s when the fossil component began to rise rapidly. The timing coincides with a sharp increase in the use of fossil fuels.

The levels of naturally released fossil methane are about 10 times lower than previous research reported. Given the total fossil emissions measured in the atmosphere today, Hmiel and his colleagues deduce that the manmade fossil component is higher than expected–25-40 percent higher, they found.

CLIMATE CHANGE IMPLICATIONS

The data has important implications for climate research: if anthropogenic methane emissions make up a larger part of the total, reducing emissions from human activities like fossil fuel extraction and use will have a greater impact on curbing future global warming than scientists previously thought.

To Hmiel, that’s actually good news. “I don’t want to get too hopeless on this because my data does have a positive implication: most of the methane emissions are anthropogenic, so we have more control. If we can reduce our emissions, it’s going to have more of an impact.”

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This study was supported by the US National Science Foundation and the David and Lucille Packard Foundation.

From EurekAlert!

111 thoughts on “Methane emitted by humans vastly underestimated, researchers find

  1. Tired of the enviro-wackos playing the methane card, just like they overplay all their cards. Prb’ly some of the wacko-leaders hopingthis will turn opinion against natural gas.

    • Yes, the incremental effect as a fraction of the total effect of methane is higher than for CO2 or H2O, but a large fraction of almost nothing is still almost nothing.

      They also forgot to mention that about 2 molecules of H2O are emitted for each CO2 molecule emitted when burning fossil fuels, putting it ahead of CO2 as the top “anthropogenic–originating from human activity–contributor to global warming [sic]” putting Methane in third place.

      • And, of course, after that 9 years in the atmosphere, methane “breaks down” into CO2 and water. These aren’t separate things, but a miniscule part of a complex system that cannot be treated separately.
        Another small part of the lie is to put agricultural animals on the anthropogenic side of the pretty picture-chart, as if it is equal to “wetlands,” while ignoring the greater volume of CO2 and methane produced by wild animals, birds, and insects. Great message production and consistency for such a dishonest and misanthropic message.

      • Excerpted from article:

        originating from human activity–contributor to global warming, ————– carbon dioxide, for instance, can persist in the atmosphere for about a century.

        So, ….. human emissions of CO2 into the atmosphere …… can persist in the atmosphere for about 100 years

        WOWEEEEEEE, ….. then that means that all of the anthropogenic CO2 that has been released into the atmosphere since 1920 ……. is still resident in the atmosphere.

        Anyone that would believe that ……… would take things back that they never stole in the first place.

    • The following solution for fugitive methane emissions has been implemented by the IPCC:

      1. A huge carbon tax must be levied on cans of Libby’s baked beans and other similar products – chili, refried beans, etc.

      2. Furthermore, all citizens must be fitted at all times with a pilot light, located near the fundament, to ignite the gaseous product before it dissipates into the atmosphere. Citizens are cautioned to wear Nomex clothing to prevent against dangerous fires and risks of spontaneous human combustion.

      3. The pilot lights are to be powered by butane or propane, and are a downsized version of the ones now worn by all ruminants, also by order of the IPCC. Regarding ruminants, the pilot light must be located no less than 6 inches from the fundament, in order to prevent scorching of the wool or hides. It is also recommended to spray the wool or hides with a flame retardant.

    • ” methane has a relatively short shelf-life; it lasts an average of only nine years in the atmosphere, while carbon dioxide, for instance, can persist in the atmosphere for about a century.”

      Both CO2 and methane have half-lives in the atmosphere of about 5 years, making them both transient and short-lived. Methane is also 200 times less concentrated in the atsmophere. I do not see that mentioned above. Mdethane’s IR absorption spectrum is also pathetic and only has a couple of narrow bands. It simply cannot warm anything as the 1st majority of IR passes is right by.

      The result is a nothing-burger.

      Going by their own climate science, in which the upper tropical troposphere is warming faster than anywhere and then sends downwelling IR to the surface and heating it, this cannot happen. We know that this region of the atmosphere is about -17ºC (and gently cooling for over 30 years, according to NASA/NOAA) and the surface at about 15ºC. A cold object cannot warm a hot object by radiation or even direct contact. It just cannot happen.

      • Charles Higley,

        You have to make a distinction between the residence time, which is 5 years for CO2 and the half life time of some surplus CO2 (whatever the origin) which is about 51 years and for CH4 which is 9 years.

        The residence time is how much is exchanged over the years and its formula is:
        mass/throughput
        Or mass/input or mass/output, if input, throughput and output are more or less the same
        For CO2 the throughput is about 150 Pg/year (50 Pg/day diurnal exchange by vegetation not included). For 830 PgC (410 ppmv CO2) in the atmosphere that gives:
        830 PgC / 150 PgC/year = 5,5 years.
        That doesn’t change the total amount of CO2 in the atmosphere with one gram as long as the sum of all inputs = sum of all outputs.
        The main in/out fluxes in this case are seasonal and highly temperature dependent.

        Only the difference between total inputs and total outputs does change the quantity of CO2 in the atmosphere and for CH4 it is the chemical oxidation rate in the higher troposphere which counts. That is a complete different formula than for the residence time and follows the Le Chatelier’s Principle: if a process in equilibrium is disturbed, it will change the reactions to oppose the disturbance.
        The formula for a simple linear reaction then is:
        e- fold decay rate = height of the disturbance / effect
        In the case of the atmosphere (with 110 ppmv above the long time equilibrium):
        110 ppmv / 2.15 ppmv/year = 51.2 years

        A lot longer than the residence time, as the residence time is near fully temperature dependent, while the removal of some extra CO2 above the equilibrium is near fully extra CO2 pressure dependent.
        A lot shorter than what the IPCC assumes, as they use the Bern and similar models, which include a saturation of the oceans and vegetation, for which is not the slightest indication (except for the ocean surface, not the deep oceans).

        One can use the extra CO2 pressure to calculate the increase of CO2 in the atmosphere, based on human emissions and the net sink rate with the above 51 years decay rate over the past 60 years:
        http://www.ferdinand-engelbeen.be/klimaat/klim_img/dco2_em2B.jpg
        Where the calculated increase is in the middle of the (temperature induced) noise…

      • Charles Higley, the second part of your comment has some problems too:
        While the overall energy of a cold object can’t heat a warmer object, the radiation energy emitted by a cold object certainly can be absorbed by a warmer object: a warmer object doesn’t know the temperature of the sending object (*) and simply absorbs any radiation energy that it receives (on the condition that it can absorb every wavelength of radiation in the IR range).
        Thus while overall a colder object can’t heat a warmer object, the total loss of energy from a warmer object to space is reduced by receiving back a (smaller) amount of energy from a colder object. That makes that it keeps warmer than without that colder object in its neighborhood…

        For CO2, the radiation energy sent back to the surface by CO2 is effectively measured over time in two stations of the US, as the specific wavelengths of CO2 (and CH4) are in parts where water vapor is not active. No matter the amount of water vapor, CO2 and CH4 add to the so called greenhouse effect:
        https://wattsupwiththat.com/2015/02/25/almost-30-years-after-hansens-1988-alarm-on-global-warming-a-claim-of-confirmation-on-co2-forcing/

    • researchers find…WE’RE ALL GOING TO DIE!

      Beng135 there is a growing army of people who are tired of the whole “the planet is dying and it is all your fault’ routine. Of course they can claim they are telling the truth because we are all going to die. We know this because so far nobody has bucked the trend i.e. human death equals 100% over time. Kind of like gravity when left to its own resources. Nobody has yet to fall up.

      The folks that need to be prevented from generating any (talking zero here) CO2 are the socialists who would have us believe Central Planning can fix anything including the planetary climate which changes despite man’s existence on spaceship earth.

      They can’t explain why the climate changes naturally but they are going to hit the pause button on it by limiting mans output of CO2. It will be AMAZING. like a David Copperfield magic act once they have control over our expenditure of CO2.

      I intend to comply just as soon as all The Chicken Little’s hold their breath and drop dead starting with the entire US NSF.

  2. Methane emitted by humans vastly underestimated, researchers find

    Yes, of course. In case CO2 emissions keep flat-lining, or start dropping, then they will need a new scapegoat to keep their scary narratives going.

    • So methane is now the new ‘evil CO2’. We all knew it wouldn’t take them long.

      There may come a day, once nearly every other gas in the sky has gradually been eliminated one by one, they’ll say it was Nitrogen wot did it!

    • If methane is 10x worse than we thought, then what does that say about the ECS due to CO2?

      Are the models now even farther wrong on their estimates of observed warming due to CO2?

      • Yep.
        And for all GHGs.
        If more methane as emitted than thought – and we know what warming occurred – then we know that the sensitivity to GHGs is less than we thought.

        Sensitivity x Emissions = Warming.
        Warming is known so more Emissions = less sensitivity to GHGs.

    • These morons don’t seem to get that they are making self refuting arguments on behalf of climate alarmism. To wit:

      We know how much the atmosphere has warmed in 170 years: a grand total of 1 deg C.

      If methane has been grossly underestimated as to its efficacy as a greenhouse gas as claimed, and given that methane emissions have increased hugely, and given the minuscule warming that has taken place as a supposed result of these methane emissions, then ipso facto:

      The actual warming effect of methane emissions must actually be far LESS than it is credited with.

      Elemental logic, and science.

  3. You know…. ruminant animals like cows appeared on earth some 50 million years ago. They happily burped and farted their way across the great grasslands for hundreds of millennia, becoming one of the most dominant class of mammals, prior too us domesticating a very few of them after the last ice age. Hard to believe the planet survived all that.

    • Tens of millions of Bison roamed and farted the North American plains until the 19th century. By the 20th century they were mostly gone.

    • And what about the days of dinos? There were lots more Co2 and lots more dino farts. I imagine a fart from an Argentinosaurus, was equal to a herd of bison (or close). I get really tired of the methane issue bouncing back and forth: yes its bad, no its not, yes it is, no its not. GEEZE.

    • I find that as I get older, I myself emit more methane. Actually that’s what I thought the headline meant at first.

      I suspect this would make us senior citizens prime candidates for population reduction schemes. Please don’t tell Greta.

    • It just occurred to me what we need to do to put the whole GW charade behind us.

      We only need to get Donald Trump to announce it will be a central theme of his second term in office to get global warming under control (oh wait, I mean “tackle climate change and the climate crisis) by taking steps guaranteed to reduce emissions in a way which is a net plus for everyone’s prosperity and assured of being effective at lowering CO2 production.
      These steps would of course be to embark on a massive nuclear power plant building effort, along with greatly enlarging and expanding and building more water retention/hydroelectric dams, which will lessen the effects of droughts and floods, both of which plans will ensure many decades of abundant and inexpensive power, save everyone money, and not require a single layer of new government bureaucrats to implement.

      Within minutes, fighting global warming will be announced to be a hateful and racist policy, all funding for it will be denied by every leftist politician, every Hollywood celebrity, and the Pope himself, and middle school dropouts from countries in northern Europe…and anyone in favor of it will be declared, along with the President, the worst of the worst of humanity.

  4. “10 times lower” and “25-40% higher” are meaningless without baseline numbers. I assume those are in the study somewhere, but unsurprisingly the press release doesn’t mention them. And the article’s title hypes only the anthropogenic increase, conveniently omitting the truly dramatic drop in the natural estimate. Pretty much what we’ve come to expect from the media.

  5. “By measuring the carbon-14 isotopes in air from more than 200 years ago, the researchers found that almost all of the methane emitted to the atmosphere was biological in nature until about 1870.”
    The researchers are clearly unfamiliar with a radiocarbon dating science. Primitive dating estimates based on a known half-life of C14 and an assumption of a constant atmospheric concentration of C14 yielded age estimates for wood which were hundreds of years off when compared to tree rings dating. For more science, see https://en.wikipedia.org/wiki/Radiocarbon_dating.

  6. Warm interglacial epochs are a geologically brief natural phenomena, occurring cyclically within longer glacial periods. The not-so-permafrost has melted and refrozen many times during previous interglacials.

    When the frozen soils thaw, natural biological processes generate methane gas from the sequestered carbon. Is this methane ‘fossil gas” devoid of C-14, due to ‘permafrost’ sequestration? Does it contain C-14, because of current thawing plus biological activity? Is it a mix of both types of C-14/non C-14 methane, confounding scientists attempts to declare certainty? Given the huge volumes of methane generated from not-so-permafrost melting as the continent spanning glaciers receded, and the additional huge volumes generated each summer as more of the not-so-permafrost melts during the Holocene interglacial epoch, we are left with a conundrum. Inquiring minds need to know….

    We do know that none of the prior interglacial not-so-permafrost melting episodes resulted in ‘run away global warming’, due to methane or any other agent. The planet atmosphere has always reverted back to grindingly cold glacial periods. It will do so again. We are just too ignorant, naive, and uninformed to predict with any certainty when this next transition will occur.

    The new knowledge gained from ABoVE is interesting and adds to our data treasury, on our human journey of self-discovery. Recognize our geologically brief, warm Holocene interglacial as the cyclical, natural phenomena it is. Set aside your negative thoughts and irrational fears… and ‘tune out’ the attention seeking little boys crying “Wolf! Wolf!” Better yet, give them a good spanking, for their feral, false alarm dishonesty!

  7. “There is no evidence to suggest natural fossil methane emissions can vary over the course of a few centuries.”

    B.S. It’s called climate change. Between 1400-1850 there was a cool period, the coolest of the entire Holocene. This had the biggest impact on the high latitudes which teeter between permanently frozen tundra and seasonally frozen/swampy taiga.
    The taiga is an ecosystem where so much methane is generated in the summer soils and lakes that it builds up and explodes from the ground to form pingos. So as the Earth warmed up post-Little Ice Age, the tundra thawed and more taiga was formed, significantly increasing biogenic methane!

    • Tens of millions of Bison roamed and farted the North American plains . By the 20th century they were mostly gone. That is certainly a natural variation

    • “There is no evidence to suggest natural fossil methane emissions can vary over the course of a few centuries.”

      Utter and complete hogwash. The changes in CH4 content in the atmosphere are routinely used to synchronize ice cores because they are so large and sudden:

      http://www.iceandclimate.nbi.ku.dk/research/strat_dating/synch_ice_core_rec/synch_ch4/

      At the end of the ice-age about 11,600 years ago the amount of CH4 in the atmosphere increased by about 50% in only 150 years. At the same time there was a sharp change in the carbon isotope ratios of the CH4:

      https://www.clim-past.net/8/1177/2012/cp-8-1177-2012.pdf

      Stone age “big oil”?

      • tty,
        Thanks for those cites! Much appreciated. Looks like they didn’t do a very effective literature search, before setting out on their methane ’tilting’ adventure, did they?

        The Planet keeps on doing its ‘natural thing’, while every little nit wiggle change in our current understanding is shouted out by the attention (and rent) seeking little girls and boys as “even worse than we thought!” They need a good spanking, no more allowance, and to be grounded (no fossil fueled transport of any kind) for a year.

      • The key phrase is “natural fossil methane emissions”.

        Fossil methane emissions aren’t biogenic and contain no 14C. I think the methane fluxes related to glacial/interglacial cycles is biogenic.

        • It is not so much whether it is fossil or not, but rather how old it is.

          CH4 from a peat bog or from melting permafrost or from decomposing clathrates is certainly biogenic, but will contain much less 14C than CH4 emitted by e. g. a cow or a termite (and even the termite may have eaten old wood with somewhat reduced 14C).

          And paleontologists have known for a long time that major climate change is very often linked to marked shifts in carbon isotope ratios, though the mechanisms for this are far from clear.

          • They were just pointing out that the large natural methane fluxes are not “fossil” methane, which does not exhibit large natural fluxes. “Fossil” methane has no 14C and are enriched with 13C relative to biogenic methane.

            Carbon isotope excursions are definitely useful paleo tools.

          • tty,

            CH4 indeed is following temperature more rapidly than CO2, where the lags are much longer. Probably because of the origin: free land (for CH4) and the deep oceans (for much of the CO2 exchange).

            When there is not much temperature change, as is the case for the past 10.000 years, there is little change in CH4 levels too:
            http://www.ferdinand-engelbeen.be/klimaat/klim_img/law_dome_ch4.jpg

            There was a slight increase of CH4 while temperature decreased over the Holocene, which may point to increased domestication of cattle and rice culture, but the main increase is since the start of the industrial revolution.

          • “which may point to increased domestication of cattle”

            Very unlikely since this implies that the increase of domesticated ruminants was not balanced by a similar decrease of wild ones.
            (Wet) rice cultivation is a more likely source. Or an increase in termite numbers through deforestation and overgrazing.

            The growth of peat bogs in the taiga zone may also be a factor. There were essentially none in the formerly glaciated areas 10,000 years ago, now there are millions of square kilometers.

        • Thawing permafrost is also a source of fossil methane.

          Pingos

          Not to mention the thawing of any outcropping source rocks themselves, the different ages of organic carbon in the taiga, and the reduction in Arctic sea ice that exposes more ocean surface near the Greenland Icecap.

  8. I can tell you that after eating sugar free candy, it’s WAY higher than they realize, and that’s just me….

  9. They didn’t break out how much is due to breaking wind. A massive oversight! Needs research. Send grant money.

  10. This report reminds me of my post in 2012 https://wattsupwiththat.com/2012/07/23/veterinary-research-and-global-warming/
    The RUMINOMICS project was a waste of time. Its only value was to give temporary employment to a few departments scattered across the EU. The so-called results were just in time for the Paris COP in 2016.

    The paper above was published in Nature and it so happens that the current editor of the Vet Record regards Nature as a Journal of high repute and impeccable standards (personal communication). Some might disagree.
    The current hype about methane has now morphed into not eating meat from ruminants. This is one pleasure I am not going to forego.
    It so happens that the radiation absorption effect (RAE) of methane CH4 is covered at the same wavelengths as that of water vapour. In most of the inhabited parts of the planet WV is at 30-40 thousand ppmv and CH4 is at about 1.8 ppmv. CH4 is therefore irrelevant as a so-called greenhouse gas.
    Methane Madness is well discussed by Forbes and Glatzle on 26-10-16
    https://wattsupwiththat.com/2016/10/26/methane-madness-the-battle-for-our-grasslands-and-livestock/
    Michael

  11. Is all this because:
    [A] CO2 emissions from western countries is declining and another ‘murder weapon’ needs to be found?
    [B] All the CO2 topics have been covered so new topics for grant money must be found?

  12. The blogger does not show any figures what the overall effect of methane in the GH effect could be. That is the starting point if we should be worried about methane or not.

    The first observation is that the absorption peaks of methane and nitrogen oxide overlap almost completely. Therefore, the contributions of the two gases are usually calculated together. Michell (1989) gives a 2 % contribution to these two gases. Schmidt et al. (2010) give 7% for ozone, methane and nitrogen oxide together. Because ozone’s contribution is about 5 %, Schmidt et al. come to the same contribution of about 2 %.

    These calculations above are based on the IPC’s GH effect definition, which has the overall GH effect value of 155 W/m2. The correct value is almost 100 % more being 270 W/m2. It is the difference between the overall SW+LW radiation to the surface (510) and the net solar insolation radiation (240) and this value is 270 W/m2. Using this value and the total absorption value of CH4+N2O, the overall contribution is only 0.7% (corresponding to 0.2 C) – totally insignificant. More scientific information here: https://www.climatexam.com/copy-of-2018-1

    The GWP values cannot be used in real warming calculations because they are integrated normally over 100 years.

    For me, it looks like the blogger has not carried out any spectral calculations to find out what are the real contributions of GH gases because there are no numbers.

    • It is pretty impossible to put a definite figure on it because it overlaps so much with water, and nobody has really ever managed to calculate that realistically, given how much the water vapor content varies in the atmosphere.

      You can check for yourself here:

      http://lorelei.uchicago.edu/modtran/

      For a tropical atmosphere with no clouds and average humidity it comes to a little less than 1.5 % of the total GH effect.

      • I have calculated the contributions of GH gases including methane. It is not impossible. The water content is not a problem, because its average amount is very well known. It is good enough to know the annual average concentrations globally.

        It is true that the absorptions peaks of methane overlap very badly with water. That is the reason why its contribution is insignificant as I showed.

  13. If methane only lasts an “average” of 9 years in the atmosphere, how can anyone today measure the methane emission rate from 200 years ago? Even if the 9 years represents a half-life, of the methane emitted in 1820, only 0.5^(200/9) = 2*10^-7 fraction (0.2 ppm) of it would still be in the atmosphere now.

    The total methane now in the atmosphere would be 2 ppm of the methane emitted in 1820 plus 4 ppm of that emitted in 1829 plus 8 ppm of that emitted in 1838 plus … 50% of that emitted in 2011, basically the sum of a geometric series.

    Only about 1 carbon atom in a trillion is Carbon-14, and the half-life for radioactive decay of C-14 is about 5700 years. A sample of methane emitted 200 years ago would have about 2.4% less C-14 than a freshly emitted sample, so that trying to distinguish 1.0 ppt C-14 from 0.976 ppt C-14 in a sample of air which contains about 1.8 ppm methane molecules would require measuring to a precision of 4*10^-20. Then, how is that measurement distributed between a tiny fraction of the molecules emitted 200 years ago and a relatively large fraction of molecules emitted recently? This sounds like an awful lot of guesswork!

    C-14 is formed in the upper atmosphere when cosmic rays convert a proton in an N-14 nucleus into a neutron. If this nitrogen atom was part of an N2 molecule, the molecule would be converted into a cyanide (CN-) ion, which would react with any other reactive molecule in the vicinity. It would take many reactions for such a C-14 atom to reach the surface, possibly not in the form of CO2. Since there are cycles in solar flares that affect the intensity of cosmic rays, the rate of formation of C-14 has probably varied up and down many times over the past 200 years, so that the “original” C-14 concentration in biogenic methane (before radioactive decay) has probably varied, possibly by more than the 2.4% decay expected over 200 years.

    It is therefore extremely difficult to establish an emission rate of methane over a period of 200 years using C-14 measurements alone. A C-14 atom can only be detected when it decays and emits a beta particle–it does not tell the researcher how many years it has been in a methane molecule.

    • The variations in the amount of C-14 in the atmosphere over the last 12,000 years or so has been pretty well determined by measuring tree-rings of a known age. However this does not tell whether the changes were due to variations in the production rate, or changes in the carbon cycle. You can however get some idea by measuring the changes in the amounts of Beryllium-10 which generally co-varies with C-14 production, but is not affected by carbon cycle perturbations.

      For what it is worth, this seems to indicate that at least the major changes in C-14 concentration that occurred near and at the end of the last glaciation, were not caused by changes in the production rate.

    • Steve Z,

      Methane levels are conserved in ice cores, where there is no measurable change due to biological activity, once the air bubbles are closed. For high accumulation sites, the average closing time (that gives the resolution), is less than 10 years over the past 150 years with some overlap with direct measurements in the atmosphere.
      The past 2,000 years can be measured with 20 years resolution.
      75,000 years with 40 years resolution.
      and finally 800,000 years with 560 years resolution.

      One can back calculate the original CH4 emissions over different periods with the 9 years e-fold decay rate (or is it half life time?)…
      Here for the past 1,000 years in the three Law Dome ice cores (20 and 10 years resolution), firn and direct measurements:
      http://www.ferdinand-engelbeen.be/klimaat/klim_img/law_dome_ch4.jpg

  14. Nobody seems to be curious about how much methane will run the temperature. Certainly there’s an answer to that, but we never see it. Probably because it’s so small as to be effectively nothing.

    Meanwhile various local governments are banning natural gas in new construction because of climate change. That will spread to shutting off gas when homes are bought and sold and to more states besides California and Brookline Massachusetts.

    So far the pitchforks and torches remain in the tool sheds.

    • According to MODTRAN a doubling of CH4 from 1.7 to 3.4 ppm will cause a temperature rise of 0.2 degrees given a US 1976 Standard Atmosphere Profile.

      At current rates this will take about 400 years.

      • tty February 20, 2020 at 1:27 pm
        According to MODTRAN a doubling of CH4 from 1.7 to 3.4 ppm will cause a temperature rise of 0.2 degrees given a US 1976 Standard Atmosphere Profile.

        Thank you for that, and yep that about what I get by working backwards from CO2’s basic sensitivity of 1.2 degrees (w/o feedbacks.) and the Global Warming Potential numbers supplied by the IPCC reports.

        And by 2100 given that methane increases about 6 or 7 ppb annually the rise would be about 0.04 degrees. That’s immeasurable and essentially nothing. But local governments are making policy based on that. The insanity really needs to stop.

  15. By hook or by crook, the anti-humanists are determined to rip fossil fuels from our society and drive us back to the stone age!

    You can bet the elites will be under no such restrictions, however!

  16. Oh No! It’s worse than we thought!

    We need a meme, people. Somebody who is up on their meme craft should do it.

  17. Just think how many grammar school faculty lounge propagandists took their classes to the theater in order to watch Al Gore “Inconvenient Truth” movies featuring drowing penguins and polar bears in an attempt to further brainwash the little kiddies. That same crowd would have preformed an even far greater service for mankind and the planet Earth had they all just stopped farting and burping.

  18. As their previous Shibboliths fail the scientific test, the Alarmists simply move on to new Alarm Fields or dig up some Golden Oldies from the past. As things continue to get better it’s always worse than we thought.

  19. If we are emitting far more methane than previously estimated, and if no one has already adjusted temperatures to match, then the conclusion is methane is far less dangerous than we thought… It can only account for a small amount of the observed warming but it takes far more of it.

    If natural methane emissions are far less than we previously estimated, then cows are far less dangerous then we thought, and a thawing permafrost is far less dangerous then we thought.

    Sooo…I guess we can all relax now.

  20. It was inevitable.
    The climate debate has become what it was always going to be.
    A fart in a thunderstorm.

  21. What’s cute about little children is how they fart when they laugh.
    Can’t have that anymore I guess.
    The occasional cortex is right – we should eat them.

  22. Several numbers used by the EPA in the past are demonstrable wrong.

    Upland soil is listed as a 30tg methane sink. This is wrong. Upland soil
    contributes natural gas to the atmosphere. It enters the soil from
    below, upwelling from deep in the earth. In soil which has adequate
    moisture, the natural gas is oxidized by microbes, contributing CO2
    to the atmosphere, so the upland topsoil as a sink is more than 100%
    wrong. When methane hits the atmosphere, it rises.

    On cattle, first of all, they do not fart. They belch. Then you would
    have to subtract the buffalo contribution because humans removed
    that source from the US. The tall grass which once covered the US
    plains would die and rot, contributing methane or CO2 to the
    atmosphere if not eaten by ruminants or prairie dogs. The grass
    frequently burned, again contributing CO2 and other gasses.

    The same upwelling natural gas on rice farms is eaten by the microbial
    culture when the paddies are not flooded. When they are flooded, the
    water causes the natural gas to rise faster than the culture can consume
    it. Is the upwelling natural gas a human contribution? If flooding land is
    a human contribution, then all natural gas upwelling from any reservoir
    is a human contribution, less the CO2 contributed by the top soil.

    NASA, in their study released January 20, 2020, says that CO2 in that
    atmosphere has a cooling effect.
    https://principia-scientific.org/carbon-dioxide-is-a-cooling-gas-according-to-nasa/

    The subject is very complicated and errors abound.

  23. I’m a little confused about the impact of methane. Isn’t it a relatively unstable molecule that will turn into CO2 and water in the atmosphere relatively quickly?

    • They are confused too, WonkotheSane. About a great many things.
      https://www.youtube.com/watch?v=Nembr1ZeRc8
      The effect of methane is very small, partly, as others mention, because its absorption spectrum overlaps with water, which dominates.

      And even if it was significant then, as you rightly point out, its short lifetime in the atmosphere means that we could fairly easily reverse any significant changes actually caused by us in the event of it being a problem. This is what the alarmists don’t like to acknowledge or discuss: The ability to wait and see that it might not be a problem blows their “we must act now” claims out of the water. Once everybody realizes that we can, and are, discovering that there is no immediate threat, then the game is up.

  24. Can someone explain how Greenland Ice Cores can exist from 200 years ago when today is supposed to be hotter than it was 200 years ago? Obviously the Medieval Warming would have caused previous Glaciers to melt in the Arctic and especially Greenland Glaciers. So the Methane would have increased in the Atmosphere. But with a 9 year life would have broken down before the LIA Glaciers formed over 300 years ago and 200 year old Glaciers wouldn’t exist with our current Modern Warming.

    • John,

      Greenland cores are taken at the top of the inland ice, which is several thousands of meters thick, thus much colder. Ice melt is very rare (once in 100 years) on the summit, that is not a problem.
      Greenland ice only melts at the edges which are far lower, thus relative warmer.
      The 9 years breakdown is on a continuous stream of methane, thus when it gets hotter, more CH4 is continuously emitted and levels go up, even when they also break down at the same speed.
      Once enclosed in ice, the air bubbles don’t change in CH4/air composition, as there is no huge biological or chemical activity to do that.
      For CO2, Greenland ice is not suitable, as frequent volcanic ash from nearby Iceland reacts with carbonate dust from sea salts and can produce CO2 in situ. For CH4, one hasn’t found similar problems.

  25. Anthropocentric underestimations, speculations, misunderstandings as in models and predictions. Nature, however, is unimpressed, and there is cooling, and there is warming, and there is unremarkable, albeit highly variable, change.

  26. Let me guess.
    Because “NASA Flights Detect Millions of Arctic Methane Hotspots” then, because Man has detected what has always been there, Man is responsible for the always-there-but-not noticed-methane-sources because an SUV or two used in launching the NASA flights used fossil fuels?
    Is that the logic?
    (My head hurts. Maybe I’ll go chew on some willow bark.)

  27. If human methane contributions are vastly underestimated, then that extra methane should be showing up in the atmosphere.
    Where is it?

  28. “Methane is the second largest anthropogenic–originating from human activity–contributor to global warming, after carbon dioxide. But, compared to carbon dioxide, as well as other heat-trapping gases, methane has a relatively short shelf-life; it lasts an average of only nine years in the atmosphere, while carbon dioxide, for instance, can persist in the atmosphere for about a century. That makes methane an especially suitable target for curbing emission levels in a short time frame.”

    After the nuclear test ban treaty, the C14 level fell to normal in 9 years.

    • Chris Hoff,

      One can’t compare the removal of the excess 14CO2 from the nuclear tests with the removal of any excess 12CO2 or methane.

      In 1960 at the peak of 14CO2 from the bomb tests, what did go into the deep oceans was the isotopic composition of that year, what returned out of the deep oceans was the composition of ~1000 years ago, long before human intervention.
      That made that in 1960 for 12CO2 some 97.5% returned the same year as was absorbed, but for 14CO2 that was only 45%. Therefore the decay rate of any excess 14CO2 is 2-3 times faster that for 12CO2.

      For CH4 that plays no role, as the removal of CH4 is a chemical one in the higher troposphere which transforms CH4 in CO2 and water.

  29. One of the side-effects of a plant-free diet for humans is less flatulence.
    Far less flatulence.

    Just sayin’…….. 🙂

    • Are you aware of beans?
      Oh sure…everyone knows they are good for the heart.
      But, the more you eat…

  30. From the article…

    “But, compared to carbon dioxide, as well as other heat-trapping gases…”

    Stopped reading right there. Pure BS article.

  31. All these wonderful studies of the multiple effects of CH4 on global warming also studiously neglect the fact that methane is measured in ppb and CO2 is measured in ppm. I haven’t referred to this study for a while but it seems it may be time again…
    https://ams.confex.com/ams/Annual2006/techprogram/paper_100737.htm
    Measurements of the Radiative Surface Forcing of Climate
    W.F.J. Evans, North West Research Associates, Bellevue, WA; and E. Puckrin

    You’ll have to open the Extended Abstract PDF to view all the info I will reference, I apologize but I’ ve never mastered linking to a PDF in one of these comments.
    The study is a spectral analysis of DW radiation to the surface to measure the contribution of the various component gases of the atmosphere. The point apparently being to prove increasing GE by comparing measured data to modeled data of the past to show an increase in DWR, which they sorta did, if not very robustly.
    The reason I bring up this work in this context is that throughout the study the DWR measurements for CH4 rarely show more than a little over 1W/m2 when the total DWR ranged from about 150-170W/m2 in the winter to 270 -300W/m2 in the summer. My point is that under almost any foreseeable scenario CH4
    will remain a rounding error level factor in the GHE.
    This study has stuck with me over the years because it was largely responsible for turning me from an agnostic to a total skeptic on CO2. A little more than half way down the study there are two graphs, one of winter measurements and the other of summer values. The winter numbers show CO2 providing about 25% of
    total DWR in the cold dry air of the subarctic, which matches the canonical value usually offered. What I found quite revealing was that when the weather was warmer and moister during the summer the CO2 contribution to total DWR dropped to only 2-4%. When you look at DWR to the surface data across the planet and over the year, you find that for most of the planet, over most of the year the fact that H2O completely dominates CO2 is a completely viable hypothesis.
    When I first encountered this I naively assumed this technique would become an instant sensation given what I saw as the terrific potential to provide the type of data necessary to actually solve some of these climate controversies we face. Sadly, although it has been nearly a quarter-century since the original fieldwork for this study was done the technique has been little copied, although I must admit it’s been several years since I’ve done a serious search for it. My more conspiratorial side wonders if there is someone out there who doesn’t want the information that this technique could provide getting out to the public.

  32. “Methane emitted by humans vastly underestimated, researchers find”

    That’ll be due to the silent emissions.

    • Methane is a powerful greenhouse gas and large contributor to global warming.
      Gerry, England February 21, 2020 at 5:45 am
      The first sentence was as far as I got before moving to the comments.

      Only one of the several lies that the other side repeats over and over and over again.

  33. I have calculated the contributions of GH gases including methane. It is not impossible. The water content is not a problem, because its average amount is very well known. It is good enough to know the annual average concentrations globally.

    It is true that the absorptions peaks of methane overlap very badly with water. That is the reason why its contribution is insignificant as I showed.

  34. “Methane emitted by humans vastly underestimated, researchers find”

    They must not have studied what happens when a persons emits some on a crowded bus in Wintertime.

  35. This seems like utter nonsense.
    The NOAA monitors methane levels in the atmosphere. If the emissions are so much higher, why is this not being detected by the NOAA’s global network of monitoring stations?
    https://www.esrl.noaa.gov/gmd/ccgg/trends_ch4/#global_growth
    Note that methane levels have been climbing since 2004, with a spike starting 2013. This might be fracking, but might not since methane levels have fluctuated in a band for the duration of NOAA’s monitoring.

  36. It’s perfectly natural that methane is a by-product of the production of Bull-…., well, you know.
    (If you don’t know, a hint. You wouldn’t want to grabit.)

  37. What if a researcher farted while setting up his atmospheric methane detecting apparatus. How many skewed results could be inside all these studies.

  38. Methane + CO₂ break down into alcohol + sugars;

    https://www.google.com/search?client=ms-android-huawei&sxsrf=ALeKk039wzjnkgeRKIVmjWbBFr_a6kQ0Kg%3A1583397549647&ei=rbpgXo6UHJ2Gk74PiJScoAc&q=methane+breaks+down+into+alcohol+and+sugar&oq=methane+breaks+down+into+alcohol+and+sugar&gs_l=mobile-gws-wiz-serp.

    Of course atmospheric methane is preserved in ice core samplings.

    No one can fathom what challenges constantly require new, never heard of “methane studies”.

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